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RUSKA 2485-930

1. BiGo 1 1 Veen RUSKA 2485 Users Manual 3 TECHNICA DESCHID 1 coers EEE BEER EEEEEDENKNE EEEE Instrument Oy C 11 Wi een ee ae Instrument Features and Functions Mass Loading Table Assembly Ins tallation K Inne ee ee site RUSKA 2485 Piston Cylinder Assembli6s High Pressure Piston Cylinder Assembli6s 4 RUSKA 2485 System Operation Jy MOI ee ee ee i CUI OUI u uuu E E E Installation and Preparation for Use Selecting a LOCALION UL a in masiipiwawakakasmaqqaqsakapkaspawdassssskaysasascaapas Setting Up the Instrument Platform Fill Pump Assembly RUSKA 2485 930 Preparation Tor UEC een INAS O Su E EEEE EEE EEE E TETTE Test Port Manifold Connections aaaaasassssaa Mass Loading Table Removal and Installation Piston Cylinder Assembllt6s
2. a Rupture Disk Re eplacement an Instrument Cover Removal and Replacement Seal and O ring Replae mehnt een Piston Cylinder Cleaning nsesebeseteiitese ea Alternate Piston Cylinder Cleaning Method ESTES CTl L unu en ee Troubleshooting Common Problems Air Trapped In the sten screen ee Fo j Learn i NOO uuu unuman aZ shana nas Troubleshooting and Changes in Operating Voltage J ODS eera eina ee Plecironie Float Position siscysiesssaacuciaisansnceanatbvansaavanasoseseraemtavencalssnideacasauuncuabar Electronic Temperature Sensor aussen iaai Appendices A CA UO u x E AE AE y A NE EREE a B Setup Kit Bills of Materlal iii IV List of Tables Title Page uns n E E E 1 Piston Cylinder Selection zart an ES Piston Cylinder Seletl on een ee ae 1 4 Typical Thermal Coeflicients are areas 2 4 Instrument Platform Functional Description aa ERE Instrument Platform Featp res uu uu uuu srne ena a ienai Er EEA Troubleshooting Changes in Operating Voltage 5 7 RUSKA 2485 Users Manual vi List of Figures Figure Title 251 BEI
3. 4 5 Mass Loading Table Installed 4 6 Mass Loading Table and Piston 5 1 Safety Head and Rupture Disk en a a 5 2 Low Range Cylinder Cleaning u uu seein Qasaqa haywaq 5 3 Mid High Range Cylinder Cleaning a s vii Vill Chapter 1 Introduction and Specifications Introduction This manual covers the operation and maintenance of the RUSKA 2485 Hydraulic Piston Gauge How to Contact Fluke To order accessories receive operating assistance or get the location of the nearest Fluke distributor or Service Center call e Technical Support USA 1 800 99 FLUKE 1 800 993 5853 e Calibration Repair USA 1 888 99 FLUKE 1 888 993 5853 e Canada 1 800 36 FLUKE 1 800 363 5853 e Europe 31 402 675 200 e China 86 400 8 10 3435 e Japan 81 3 3434 0181 e Singapore 65 738 5655 e Anywhere in the world 1 425 446 5500 Or visit Fluke s website at www fluke com To register your product visit http register fluke com To view print or download the latest manual supplement visit http us fluke com usen support manuals Safety Information N Warning Pressurized vessels and associated equipment are potentially dangerous The apparatus described in this manual should be operated only by personnel tra
4. 4 17 Discharging the Hand Pump While at Pressure 4 17 Returning to Atmosphere nn 4 18 Generating Pressures Greater than 20 000 PSI 1400 Bar 4 18 Generating Pressure uuu uuu seen een 4 18 Adjusting Float Po811100 u u0ssuienaeeaannaeinn 4 19 Recharging the Hand Pump While at Pressure 4 19 Recharging the Intensifier While at Pressure 4 19 Discharging the Intensifier While at Pressure 4 20 Discharging the Hand Pump While at Pressure 4 21 Returning to Atmosphere n 421 Op onal Hardware er akupaqaspassktua 422 Electronic Float POSION ze 422 Electronic Temperature Sensor anne 4 22 5 Maintenance and Troubleshooting ITS IC OT ee een IN FAM IDE STAIN uuu u ONE censten INNERN r EEE ANGEHEN HRERNERGE CIEEREERNCHE NEUERER Instrument Platform Mailntenance 1 Oil aA Hose este Instrument Platform Cleaning Level Vial A GUS teil ea Instrument Platform Lubrication Packing Adjustment for Valves
5. 10 Rotate the hand pump spindle clockwise TWO FULL TURNS 11 Open pressure valve B and close reservoir valve A and intensifier valve C 12 Rotate the hand pump spindle clockwise to generate pressure 13 Continue to rotate the hand pump spindle clockwise until the pressure monitor indicates the pressure noted earlier in this section then slowly open system valve D 14 Rotate the hand pump spindle counter clockwise to continue reducing the system pressure Discharging the Hand Pump While at Pressure When reducing pressure in the system the hand pump may reach the counter clockwise travel limit before the desired pressure s obtained To allow further depressurization of the system the hand pump may be discharged while the system remains at pressure To discharge the hand pump while the system is at pressure 1 Verify that pressure valve B is open and adjust the hand pump position so that approximately one quarter of the pump travel remains in the counter clockwise direction 2 Close system valve D and note the system pressure indicated on the pressure monitor Carefully rotate the hand pump spindle counter clockwise until the pressure monitor indicates between zero and 500 psi 35 bar 4 Open reservoir valve A and rotate the hand pump spindle clockwise until approximately one quarter of the pump travel remains in the clockwise direction 5 Close reservoir valve A and carefully rotate the hand pump spindle clockwise to g
6. Deadweight Gauge Masses The components of a deadweight gauge mass set are calibrated to provide knowledge of individual mass values as well as an estimate of the contribution to the total uncertainty in the pressure measured with the instrument Preservation of the condition of the masses is crucial to long term stability and reliability Proper handling such as careful and deliberate loading and unloading removal of incidental contamination such as fingerprints and deadweight gauge oil and proper storage of the masses will prolong the reliability of the calibration values The recalibration schedule for a well preserved mass set is typically about 3 or 4 years Heavily used or less well preserved sets will likely require more frequent calibrations Calibration of deadweight gauge masses is typically performed through direct comparison of individual masses with standards of known mass measured on a precision balance or mass comparator The calibration report for a mass set used with a high accuracy deadweight gauge will typically include individual mass and density values as well as uncertainty and traceability information Masses used with lower accuracy deadweight gauges may not list individual mass values only nominal values of mass or pressure and a tolerance to which they were measured or adjusted In either case the calibration documentation is an important part of the mass set and should be preserved with the same care as the individual
7. Instrument Features and Functions Functional Description 013 Pressure Monitor Dial Gauge The pressure monitor provides a direct reading of the pressure applied to the hand pump In the high pressure version RUSKA 2485 950 when the integral intensifier is activated the pressure monitor also indicates approximately 1 5th of the system pressure Internal Reservoir Cover The instrument is provided with a 250cc capacity internal reservoir The internal reservoir cover prevents contamination of the fluid in the reservoir External Reservoir Port RUSKA 2485 950 Only Should the internal reservoir have insufficient capacity for high volumes of work a port is provided on the rear of the instrument for attaching an external high capacity reservoir such as the RUSKA 2419 800 1500cc reservoir and a high flow transfer pump Model 5202 When an external reservoir is not connected the external reservoir port becomes a convenient location to attach a manometer for establishing a precise measure of zero pressure 016 Reservoir Source Valve RUSKA 2485 950 Only The reservoir source valve is used to select between the internal reservoir and an external reservoir or manometer Reservoir Relief Valve RUSKA 2485 950 Only The internal reservoir plumbing is protected from inadvertent over pressure through the use of a relief valve set to approximately 100 psi Test Port Manifold And Adapters In addition to the test port at the base o
8. Features and Functions WSS Si N Mm mee INI PUUL ZZ ee a A s L 1 gmd06 eps Figure 3 5 Right Side View RUSKA 2485 950 without Cover RUSKA 2485 Users Manual gmd07 eps Figure 3 6 Top View RUSKA 2485 950 without Cover Technical Description 3 Instrument Features and Functions HANGER MASS SEQUENCE 01 PISTON CYLINDER ASSY BOX 1 OF 5 5 11 O 5 09 9 08 s i BOX 5 OF 5 gmd08 eps Figure 3 7 Mass Set in Boxes RUSKA 2485 Users Manual 3 16 RESERVOIR CAP LOOSEN TO OPERATE GAGE FLUID LEVEL VIEWING WINDOW IJ OOOOOOOOOO OOOOOOOOOOQ ed 0000000000 TIL Oo0000000000 OOOOOOOOOO Fr a gt gmd09 eps Figure 3 8 Instrument Platform with Partial Mass Set Loaded RUSKA 2485 930 and RUSKA 2485 935 Technical Description 3 Instrument Features and Functions an MAINS 0027 PONE amp SOROL ITCH ae Se JA en 2 PUMP SUCMON BOWER SEE ey S E gmd10 eps Figure 3 9 Rear View RUSKA 2485 903 and RUSKA 2485 935 RUSKA 2485 Users Manual BEARING amp WASHERS 1 5 126 2 2450 2 12 REF on PISTON OR 2485 999 CYLINDER RETAINING NUT 2485 905 001 O RING 54 703 008 POLYPAK 72 55 HOUSING SPACER 2485 950 033 HANGER MASS MINI 2485 950 035 POLYPAK 72 33 HOUSING SPACER 2485 950 033 MAIN PRESSURE HOUSING 2485 900 011 OR 2485 900 87000 K Y 2 S
9. Maximum Sink Rate See Table 1 1 Refer to Table 1 2 for a sample error analysis Table 1 2 Piston Cylinder Selection noe NomMal Pressure Minimum Optimum Pressure Model Maximum Sink Rate Uncertainty Increment Increment amp Performance i i Pressure Medium Number mm Inches Capability Designation Unit of Measure Range 10 psi Kg 60 1000 psi 2485 981 0 5 0 02 0 0025 P100 100 psi Kg 600 10000 psi 2485 982 0 5 0 02 0 0035 P200 200 psi Kg 1200 20000 psi 2485 983 0 5 0 02 0 0035 P600 600 psi Kg 9 3900 60000 psi 2485 997 1 0 0 04 1 3 RUSKA 2485 Users Manual 1 4 Table 1 3 Piston Cylinder Selection continued Unit nom aller ue Minimum Optimum Pressure Model Maximum Sink Rate Uncertainty Increment Increment amp Performance Se Pressure Medium Number mm Inches Capability Designation Unit of Measure Range P100 100 psi Kg 600 10000 psi 2485 992 0 5 0 02 0 0035 P200 200 psi Kg 1200 20000 psi 2485 993 0 5 0 02 0 0035 10 bar Kg 60 1000 bar 2485 996 0 5 0 02 0 0035 Mass Set Specifications Mass Material Nonmagnetic austenitic 300 series stainless steel Storage case Dimensions First Case Height 33 7 cm 13 2 in Masses Included Width 33 0 cm 13 in Depth 25 4 cm 10 in Weight 16 kg 35 Ib Other Cases Height 31 8 cm 12 5 in Width 33 0 cm 13 in Depth 20 3 cm 8 in Weight 23 kg 50 Ib Mass Denominations l each 1 9 kg hanger mass 19 each 5 0 kg large platters
10. NS Ss X j Z SS SS SSS S7 AV I N 0 N Cee zz G ASS II WR L Z A men nme nn Oe FALL LLL GL Z 7 lt lt ZZ 2 eS MASS TABLE MINI 2485 950 036 TABLE SUPPORT 2485 925 002 CYLINDER SPACER 2485 925 004 O RING 54 703 14 CYLINDER KEEPER 2485 950 005 HOUSING EXTENSION 2485 950 034 COUPLING 2485 950 032 HANGER MASS REF 2485 940 001 2485 940 002 REF Ml Vs gmd11 eps Figure 3 10 Section View of Pressure Column Extended Range Column and Extended Range PIC RUSKA 2485 950 3 18 BEARING amp WASHERS 12 2 2450 2 12 RETAINING NUT 2485 905 001 MAIN PRESSURE HOUSING 2485 900 011 OR 2485 900 87000 Z lt Z f ZZ Z D SSS DUN aa N RZ III RI NG i JS Me ID DKW Y EEE SSS LLL Z N N 7 N N N IN N ER 7 Z j Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z 7 AN 17 Technical Description Instrument Features and Functions 3 TABLE ASSEMBLY 2485 905 CYLINDER SPACER 2485 905 004 R 54 703 117 PISTON SPACER 2485 930 004 HOUSING SPACER 2485 950 033 HANGER MASS REF 24 85 940 001 DRIVE SLEEVE 2485 915 2485 940 002 REF gmd12 eps Figure 3 11 Section View of Column Assembly RUSKA 2485 930 or RUSKA 2485 950 with Low Range P C RUSKA 2485 Users Manual 3 20 Chapter 4 RUSKA 2485 System Opera
11. Piston Cylinder Assemblltes Sal ee ee BS NN a RANDE SREREERBENERERENEEENEREEUEURERIENEFEERSTEREREENEERESEREE EUR EENENERERSTERERENEEUEREGEN Piston Cylinder Identification Piston Cylinder Installation and Exchange RUSKA 2485 930 md RUSKA 2485 U EE ee Removing the Mass Loading Table Assembly Removing a Piston Cylinder Assembly or Shipping Plug RUSKA 2485 930 and RUSKA 2485 950 Installing a Piston Cylinder or Shipping Plug RUSKA 2485 930 and RUSKA 2485 950 u u uu uy asmanapasashanasmaqhalkusaaiqaasqiiuapaykasaqpasqi Installing the Mass Loading Table Assembly RUSKA 2485 930 and RUSKA 2485 950 Operating Procedure for the RUSKA 2485 Deadweight Gausge Establishing Atmospheric Pressure aaaasssssssssssa Level the Instrument Platformi u uu una Recharge the Hand Pump usssseeeeeeeeeeseseennnnnnnnnnnennnnnnnnnnnnnnnnnnnnnnnnnnennn Load the Masses and Pressurize the System Install the Hanser Massen sessantsnunnseevareaadeaace MAG Ober Massen ee ee R tate fhe V1 ASSES anne Fine Load Ad using Adj st Float Positions
12. a vertical direction If the axial motion of the piston is not vertical the force acting on the piston and hence the pressure generated 1s reduced as a function of the cosine of the angular deviation from vertical This situation is often referred to as a cosine error but can be corrected for using the following equation F F cos where F axial force acting on the piston F vertical force and 0 angular deviation of piston axis from vertical An angular displacement of 0 25 degrees from vertical results In a reduction in pressure of approximately 10 parts per million Since a significant deviation from vertical may also affect the performance of a deadweight gauge it is common to adjust the piston to vertical within a fraction of a degree using a sensitive spirit level typically attached to the instrument base rather than measure the angle and applying corrections 2 5 RUSKA 2485 Users Manual Buoyant Effect of the Air 2 6 Archimedes principle shows that the vertical force exerted by an object submerged in a fluid is reduced by an amount equal to the mass of the fluid displaced The magnitude of this buoyant force can be determined as a function of the volume of the object and the density of the fluid displaced Since the volume of an object can be determined as a function of its mass and density and the volumes of masses used on a piston gauge are usually not measured directly it is common to determine the buoyant for
13. at the lower travel limit and the pressure monitor indicates between zero and 500 psi 35 bar then slowly open pressure valve B Generating Pressures Greater than 20 000 PSI 1400 Bar N Caution Although not essential it is recommended that the procedure in Chapter 4 Generating Pressure Greater than 20 000 Psi 1400 Bar be followed to generate approximately 20 000 psi 1400 bar to pre charge the intensifier prior to proceeding with the procedure If the low pressure procedure is not performed first the likelihood of recharging the intensifier while at pressure is much greater Generating Pressure Generate between 18 000 and 20 000 psi 1250 and 1400 bar using the procedure described in Chapter 4 Generating Pressure Greater than 20 000 Psi 1400 Bar 1 Close intensifier valve C and carefully rotate the hand pump spindle counter clockwise until the pressure monitor indicates between zero and 500 ps 35 bar Open pressure valve B and rotate the hand pump spindle counter clockwise until the pump position indicator approaches the counter clockwise travel limit Rotate the hand pump spindle clockwise approximately one quarter turn to remove any spindle nut backlash Close reservoir valve A and rotate the hand pump spindle clockwise to generate pressure As pressure develops in the hand pump it will increase rather rapidly until the intensifier plunger begins to move At this point the intensifier will begin to increa
14. device such as the electronic float position display to provide a reliable digital indication of the deadweight gauge temperature The PRT is mounted in the main pressure housing of the deadweight gauge n place of the liquid in glass thermometer used when this option is not installed The adjustment and calibration procedures for the electronic temperature option are included in the operating manual for the display device u yor TAGE SHOWN THROUG WINDOW DOOR CLOSED 24 866 FITTING GLAND B 72 5KPSI MAWP Le SELECT NER Ru AND RO PROPER POSITION I ss T AR up FUSE HOLDER PULL OUT DOOR OPEN gmd19 eps FITTING ADAPTER 5 16 TO 1 4 TUBE 60KPSI MAWP 24 948 prie ADAPTER 24 94 10KPSI MAWP FITTING ADAPTER 3 8 NPT 1 213 10KPSI MAWP FITTING ADAPTER 10KPSI MAWP PART OF 24 944 av LAND eokes WANE gmd20 eps Figure 4 4 Test Port Manifold and Adapters 4 22 RUSKA 2485 System Operation A Optional Hardware MASS LOADING TABLE SUPPORT TABLE PIN SS ESTES ZINN G THRUST BEARING AND WASHERS En WAY r p ZN Z AL DA N E Uy ROLLER PIN N Wei 1 CYLINDER SPACER RETAINING NUT WAS IE A tk VL II PISTON CYLINDER NAN N N Sa Il O RING 54 703 117 Z lt a HANGER MASS QA MAA N X x WN YR MAIN PRESSURE DRIVE SLEEVE HOUSING PISTON SPACER HOUSING SPACER 2485 930 004 2485 950 0
15. for troubleshooting Adjusting Float Position As the pressure approaches that required to float the piston reduce the rate of hand pump spindle rotation and slowly approach the proper float position If the float position or system pressure is too high 1 Rotate the hand pump spindle counter clockwise until the proper pressure or float position is obtained 2 Rotate the hand pump spindle an additional one quarter turn counter clockwise and then carefully clockwise to restore the pressure or float position and to remove any spindle nut backlash This will prevent the pump plunger from creeping out of the pump housing which could result in erroneous pressure readings Recharging the Hand Pump While at Pressure On occasion the hand pump will reach the full clockwise travel limit preventing further pressurization The hand pump may be recharged while the system remains at pressure To recharge the hand pump while the system is at pressure 1 Close intensifier valve C and note the pressure indication on the pressure monitor 2 Rotate the hand pump spindle counter clockwise until the pressure monitor indicates between zero and 500 psi 35 bar and open pressure valve B 3 Continue rotating the hand pump spindle counter clockwise until the pump position indicator approaches the counter clockwise travel limit 4 Rotate the hand pump spindle clockwise one quarter turn and close pressure valve B Carefully rotate the hand pump spindle cl
16. function of pressure the fractional change in area per unit of pressure and b Coefficient of elastic distortion as a function of the square of the pressure the fractional change in area per unit of pressure squared p Square of nominal system pressure Temperature Piston pressure gauges are temperature sensitive and for accurate measurements corrections must be applied for deviations from the reference temperature When the temperature of a piston cylinder assembly is above the reference temperature the effective area will be larger than at the reference temperature and the pressure for a given load will be less When the temperature of the piston cylinder assembly is below the reference the effective area will be smaller and the pressure for the same load will be greater Depending on the magnitude these thermal changes may have a significant effect on the measurements Corrections for temperature are applied at the time of a measurement using the following relation A Ar 1 C t r e where A Effective area corrected to working temperature Aia Effective area at the reference temperature C Coefficient of thermal expansion the fractional change in area per unit of temperature t Piston cylinder working temperature and r Piston cylinder reference temperature The thermal coefficient for a piston cylinder assembly is directly dependent on the materials used The appropriate value for the coefficient a
17. includes a hanger mass for maintaining a low center of gravity while supporting the full load nineteen 5 kilogram platters and incremental denominations in a 5 3 2 1 sequence down through 200 grams Each mass in the set is marked with the nominal mass denomination a sequence number and the serial number of the set for traceability When supplemented with a laboratory style mass set typically including 10 mg through 100 g masses the load can be trimmed to generate any pressure within the range and sensitivity of each piston cylinder assembly The mass set is supplied in 5 storage cases The storage case for the hanger mass and incremental platters also accommodates three piston cylinder assemblies Refer to Figures 3 7 and 3 8 Mass Loading Table Assembly The mass load on the RUSKA 2485 is transmitted to the piston through a conical arrangement in the mass loading table assembly that locates on the spherical end of the piston This locating method which allows any minute imbalance in the load to be self aligning and self balancing promotes a higher level of performance than with a rigidly mounted load which can result in bent broken or worn piston cylinder components The piston cylinder protection provided by the precision fit of the components in the RUSKA 2485 mass loading table assembly eliminates the necessity for a secondary piston and guide bushing which could result in increased friction and reduced performance Installation Ki
18. instrument the pressure must be removed and the valves set to a position that will not trap pressure in any portion of the system During operation of the system a warning sign notifying personnel of the state of the system should be placed in close proximity to the system Versions of the instrument that include the drive motor option require a grounded 115 or 230 VAC power source To prevent electrical shock when servicing an instrument with the drive motor option the power switch must be set to the off position and the power cord disconnected from both the instrument and the power outlet The RUSKA 2485 is shipped from the factory n a special configuration A small amount of pressure is trapped in the instrument to prevent air from contaminating the hydraulic system The procedure to remove this pressure described later in this section must be followed to prevent damage to the delicate internal components and to prevent injury to personnel 4 1 RUSKA 2485 Users Manual Installation and Preparation for Use Selecting a Location The RUSKA 2485 should be installed in a location where the temperature is maintained between 18 degrees and 28 degrees Celsius and the relative humidity is between 20 and 75 Temperature stability may be more important than the actual temperature A change in the temperature of 1 degree per hour may be excessive for some pressure measurements The installation location should be free from excessive personn
19. is properly positioned in the pulleys on the drive motor and the drive sleeve Connect the power cord supplied with the instrument to the power cord receptacle on the drive motor assembly and then to the power outlet at the installation location Depress the 1 on the power switch and verify that the drive sleeve rotates in the clockwise direction Depress the 0 to switch the power off A thermo well is located in the front right quadrant of the base of the main pressure housing This well allows for the temperature measurement of the column and Piston Cylinder This well will accept a liquid in glass thermometer or an electronic temperature probe PRT An optional thermometer assembly is available from Fluke under the part number 2485 202 913 If an electronic temperature measurement is desired the RUSKA 2456 Piston Gauge Monitor may be the optimal choice The RUSKA 2456 piston gauge monitor will make an electronic temperature measurement as well as measuring the float position of the mass platters Contact your Fluke Sales representative for more information on the RUSKA 2465 PGM Tighten the fitting into the housing about 1 4 turn past finger tight If a thermometer is used position the thermometer so the graduations show through the slot in the thermometer support tube and rotate the support tube so that the temperature can be measured with the masses installed It may be beneficial to apply heat sink compound into the temperature will prior
20. mass loading table assembly is properly installed and is not damaged Troubleshooting and Changes in Operating Voltage Table 5 1 Troubleshooting Changes in Operating Voltage Drive motor indicator lamp lights but the drive motor Disconnect the power cord and check drive motor does not run Fill pump indicator lamp lights but the fill pump does Verify that the power pigtail that protrudes from the not operate bottom of the drive motor housing is plugged into the fill pump housing under the back side of the base Replacement fuse required Part number 26 216 1 amp slow blow Changing operating voltage To switch voltages from 110 vac to 220 vac disconnect the power and switch the voltage selector on the back of the unit Refer to figure 4 1 in the user s manual The unit should operate as well on 50 or 60 hz power Air in the system allowing the reservoir to run dry The air may be removed from the system using the instructions detailed in Chapter 5 Air Trapped in the System of the operator s manual 5 7 RUSKA 2485 Users Manual Options Electronic Float Position If the float position of the piston cylinder assembly is not being measured correctly by the electronic float position indicator verify that the electrical connectors to the sensor are secure and that the sensor is properly adjusted refer to Chapter 4 Electronic Float Position N Caution The hanger mass and at least one other mass 2 kilogra
21. of the piston cylinder assembly The seal configuration of the keeper allows the use of a standard elastomeric O ring seal at the base of the cylinder while providing positive sealing up to 72 500 psi 5000 bar The design of the keeper sealing surfaces enhances the durability and allows extended use of the seals The lower seal on the keeper is the same configuration as the seal used on the test port manifold Table 3 2 Instrument Platform Features 08 ana losene O nen on rumpspndeome 3 7 RUSKA 2485 Users Manual a Forom ra 3 Technical Description Instrument Features and Functions S200 0200 8200 EZOO TWNOLLdO C Jj C j m N s IL 1 Same i n FU u nay ASD I 5000 a _ 000 T gmd02 eps Figure 3 1 Front View RUSKA 2485 950 similar to RUSKA 2485 930 3 9 RUSKA 2485 Users Manual m ca ao mn 10 lt Ce V ca ao 1 lt ca ATOT i Figure 3 2 Rear View RUSKA 2485 950 similar to RUSKA 2485 930 gmd03 eps 3 Technical Description Instrument Features and Functions gmd04 eps Figure 3 3 Right Side View RUSKA 2485 950 similar to RUSKA 2485 930 3 11 RUSKA 2485 Users Manual ND S N DR oO oO O oO ep ep Figure 3 4 Top View RUSKA 2485 950 similar to RUSKA 2485 930 OPTIONAL gmd05 eps Technical Description 3 Instrument
22. over the piston cylinder assembly and cylinder keeper for the higher ranges and tighten the retaining nut As the o ring and or seal compress some amount of feedback in the form of resistance will be felt by the operator Continue to tighten the nut until the o ring seal compression is complete as indicated by a sudden increase In resistance when the cylinder spacer inside the nut contacts the top of the main pressure housing Secure the nut using the spanner wrench part number 94 618 provided in the installation kit Piston Cylinder Assemblies Piston Cylinder Assemblies When a piston cylinder assembly is not in use it should be placed in the storage container to prevent contamination and damage to the precision finish surfaces When a piston cylinder is submitted for recalibration the mass loading table assembly should accompany the piston cylinder assembly The mass of each of these components as well as the position of the reference plane distance from the top loading surface of the weight loading table to the bottom of the piston should be reevaluated periodically General The heart of the RUSKA 2485 deadweight gauge is the piston cylinder assembly The precision fit of the pistons into the cylinders provides a very high level of sensitivity with very low sink rates Several denominations are available to best match the deadweight gauge application In some applications more than one denomination may be required The time requir
23. plane of the instrument under evaluation multiplied by the density of the fluid approximately 0 03 psi per inch or 0 08 bar per meter For many high resolution and low pressure instruments a manometer may be necessary to establish a precise zero for the instrument under evaluation 4 4 9 RUSKA 2485 Users Manual Level the Instrument Platform Adjust the level of the instrument as necessary each time the instrument is repositioned and each time a significant mass load change has been made Rotate the adjustable support legs until the level vial indicates a level condition Refer to Figures 3 1 through 3 4 to locate the adjustable support legs and the level vial Recharge the Hand Pump Precision pressure measurements rely on the thermal stability of the pressure system The action of changing pressure in the system induces significant thermal instability To minimize the necessity for recharging the hand pump while at pressure and therefore inducing further thermal instability the hand pump should be fully recharged prior to initial pressurization of the system Refer to Chapter 4 Valve Operation Procedure for RUSKA 2485 930 RUSKA 2485 935 and Valve Operating Procedure for RUSKA 2485 950 for the appropriate valving techniques for recharging the hand pump Load the Masses and Pressurize the System The mass loading table assembly of the RUSKA 2485 deadweight gauge provides a high degree of protection for the piston cylinder assem
24. pressure builds in the system If more than one quarter turn of the hand pump spindle is required to generate pressure in the system it may be contaminated with air There are several other situations besides air being trapped in the system which can also result slow pressurization A large volume connected to the test port manifold will cause the system pressure to build more slowly than with a smaller volume attached More of the hand pump travel or more hand pump strokes may be required to fully pressurize a large volume If an instrument such as the RUSKA 2413 Differential Pressure Cell which incorporates a diaphragm type sensor that must move to the end of a cavity before pressure builds is attached to the system the response of the hand pump will appear as if air is trapped in the system but is the normal response for the application After confirming that air has indeed been trapped in the system the valves can be manipulated to isolate portions of the system to determine where the greatest amount of air is trapped Figures 4 1 and 4 2 are plumbing schematics that can be used to identify the appropriate valves to isolate segments the system For each segment recharge the hand pump per Chapter 4 Valve Operating Procedure for RUSKA 2485 930 RUSKA 2485 935 or Valve Operating Procedure for RUSKA 2485 950 as appropriate 1 Verify that the hand pump spindle backlash has been removed and close the appropriate valves to isolate
25. the float position This will provide better control of the float position by remove any spindle nut backlash and developing enough pump pressure to overcome the friction of the seals in the intensifier Recharging the Hand Pump While at Pressure On occasion the hand pump will approach the full clockwise travel limit while the system is under pressure The hand pump may be recharged while the system remains at pressure To recharge the hand pump while the system is at pressure 1 Close system valve D and note the system pressure indicated on the pressure monitor 2 Carefully rotate the hand pump spindle counter clockwise until the pressure monitor indicates between zero and 500 psi 35 bar 3 Open reservoir valve A and continue rotating the hand pump spindle counter clockwise until the pump position indicator approaches the counter clockwise travel limit 4 Rotate the hand pump spindle clockwise one quarter turn and close reservoir valve A Carefully rotate the hand pump spindle clockwise to generate pressure 6 Once the pressure monitor indicates the same pressure noted earlier slowly open system valve D Recharging the Intensifier While at Pressure On occasion the intensifier will reach the full stroke limit while the system is under pressure The intensifier may be recharged while the system remains at pressure There are two indications to the operator when the intensifier plunger has reached the full stroke limit If
26. the intensifier is at full stroke prior to closing intensifier valve C for high pressure operation as described in Chapter 4 the pressure monitor indication will not change in rate as the pump pressure approaches approximately one fifth the test port pressure The more typical indication is that when the intensifier plunger reaches the full stroke limit while pressurizing the test port the pressure monitor will indicate a sudden increase in the rate of pressurization The pressure at which this occurs is important to the following procedure 4 19 RUSKA 2485 Users Manual To recharge the intensifier while the system is at pressure 1 Note the pump pressure as described above and close system valve D 2 Carefully rotate the hand pump spindle counter clockwise until the pressure monitor indicates between zero and 500 psi 35 bar 3 Open reservoir valve A and continue rotating the hand pump spindle counter clockwise until the pump position indicator approaches the counter clockwise travel limit 4 Rotate the hand pump spindle clockwise one quarter turn 5 VERY SLOWLY open intensifier valve C 6 Close pressure valve B and rotate the hand pump spindle clockwise As the pump begins to develop pressure the intensifier plunger will move towards the low pressure end of travel Continuing the rotation of the hand pump will force the intensifier plunger to the fully recharged position as indicated by a sudden increase in the pressure indi
27. the system all valves open 2 Remove the instrument covers 3 Open the valve to the maximum open position 4 Loosen the packing gland locking device 5 Use a torque wrench to tighten the packing gland to 60 FT LBS 81 3 N M Ifa torque wrench is not available tighten the packing gland approximately 1 16 turn gt gt Pressurize the system and check for leaks If the packing still leaks relieve all pressure from the system and repeat steps 2 thru 5 If packing does not seal after several attempts it needs to be replaced Contact Fluke for parts and procedures 8 Reinstall the packing gland locking device 9 Reinstall the instrument covers Rupture Disk Replacement 5 2 If the pressure in the hand pump exceeds the rating of the rupture disk in the safety head the rupture disk will burst and must be replaced with one of the same rating before the instrument can safely be returned to service Refer to Appendix B for the part number and rating of the rupture disk Replace the rupture disk according to the following instructions oe ae A Maintenance and Troubleshooting Maintenance A Caution Do not attempt to recharge the hand pump until the rupture disk has been replaced as air will be pulled into the hydraulic system Remove the instrument cover according to Chapter 5 Instrument Cover Removal and Replacement Close reservoir valve A and pressure valve B and if applicable RUSKA 2485 950 intensifier valv
28. the two positions The horizontal separation between these positions has no influence on the pressure gradient The correction for the pressure head can be accomplished using the following equation H hD G G where H Head pressure h Column height positive value if the test device reference plane is higher than the reference plane of the standard D Pressure fluid density G Local gravitational acceleration in m s and G Standard gravitational acceleration 9 80665 m s not used for S I units 2 7 RUSKA 2485 Users Manual The density of a fluid increases as a function of pressure The increased density results in a greater head pressure for a given column height With most hydraulic systems the change in fluid density is so small relative tot he magnitude of the system pressure required to change the fluid density that hydraulic head corrections are usually not adjusted for different system pressures and the density of the fluid is usually treated as a constant Further because head corrections are typically relatively small temperature and gravity adjustments to fluid head corrections are typically ignored However it is recommended that the influences are calculated thereby allowing the user to determine if they are to be ignored or included in the total system error budget The datum for pressure head corrections when using a hydraulic deadweight gauge is generally located at a position near the bottom of
29. to pressurize the test port This condition will be indicated when the pressure monitor shows a sudden decrease in the rate of re pressurization Note this pressure monitor reading for use later in this procedure 2 Close system valve D and carefully rotate the hand pump spindle counter clockwise until the pressure monitor indicates between zero and 500 psi 35 bar Open reservoir valve A then VERY SLOWLY open intensifier valve C 4 Continue rotating the hand pump spindle counter clockwise until the pump position indicator approaches the counter clockwise travel limit 5 Rotate the hand pump spindle clockwise one quarter turn and close reservoir valve A RUSKA 2485 System Operation Valve Operating Procedure RUSKA 2485 950 6 Rotate the hand pump spindle clockwise until the intensifier plunger reaches the full stroke limit This may require as much as 26 full rotations of the hand pump spindle The indication that the intensifier plunger has reached the full stroke limit is that the pressure monitor will indicate a rapid increase in pump pressure 7 Carefully rotate the hand pump spindle counter clockwise until the pressure monitor indicates between zero and 500 psi 35 bar 8 Open reservoir valve A and continue rotating the hand pump spindle counter clockwise until the pump position indicator approaches the counter clockwise travel limit 9 Rotate the hand pump spindle clockwise one quarter turn and close pressure valve B
30. 1 each 3 0 kg small platter l each 2 0 kg small platter l each 1 0 kg small platter 1 each 0 5 kg small platter 1 each 0 3 kg small platter l each 0 2 kg small platter l each 0 1 kg to 0 01 g trim set Adjustment Tolerance Each mass in the set is completely machined to the nominal kilogram mass denomination apparent mass versus brass standards e g 8 4 g cm to within the adjustment tolerance of 15 ppm or 3 0 x 10 kilogram whichever is greater Nominal values within this tolerance are traceable to the U S National Institute of Standards and Technology Mass Identification Each mass in the set is permanently marked with the serial number of the set a sequence number and the nominal mass denomination Calibration Tolerance All masses are calibrated using precision balances and are traceable to the U S National Institute of Standards and Technology Individual mass values are reported to an uncertainty to 5 ppm or 5 0e 07 kilogram whichever is greater Total tare includes mass of piston mass loading table and compensator Optional Class S 1 Laboratory Mass Set Chapter 2 Piston Pressure Gauge Measurement Considerations Measurements of pressure using a piston pressure gauge are limited by disturbances resulting from various influences including environmental effects and operating procedures as well as certain physical aspects of the equipment The effects of these disturbances can be reduced by exercisin
31. 33 gmd21 eps Figure 4 5 Mass Loading Table Installed MASS LOADING TABLE DURING INSTALLATION CLEAN OIL FROM THIS AREA TABLE SUPPORT E 1 CYLINDER PISTON gmd22 eps Figure 4 6 Mass Loading Table and Piston 4 23 RUSKA 2485 Users Manual 4 24 Chapter 5 Maintenance and Troubleshooting Introduction When operated according to the recommended procedures the RUSKA 2485 deadweight gauge requires only minimal maintenance to sustain operation for extended periods The most important factor in the operation of the instrument is diligent and methodical handling of the piston cylinder assemblies and the mass set Improper use will lead not only to unexpected maintenance and repair but can also increase the risk of injury to the operator Following the guidelines in this section will minimize the risk of damage to the instrument and injury to the operator and will prolong the life of the instrument There are several deadweight gauge performance characteristics described in the following sections that should be expected during normal operation These include pressurization rates sink rates and others If the instrument fails to provide such feedback to the operator the condition should be investigated prior to continued operation of the instrument Refer to Chapter 5 Troubleshooting Common Problems for troubleshooting Maintenance This section describes the maintenance steps required to preserve the performan
32. A 1 Conversion Factors Cag a P 6 em Where Pa pascal MPa megapascal N newton M meter PSI pounds per square inch A 7 RUSKA 2485 Users Manual 9 6 sweu ssew q sn d aie ssew qi 9010 q I IS IS ul 9910 4 q7 Uysseui qi 99 086 1p x p sn q ui ql O SOSSEWN ed z uunip ui J Aysusq JUNSSIU4 sse IVNINON uinip uu J IX LEC6G ESL x 6 uuni oo 1809 dus Oo I sd MOWU Yd Bunssald BOUBIOJON ld q punod S Ss s lt is sS OSS JUICY QUEL sd g y KoueKong 9 QHAEIO vu 1 O EZ v y ui qi wio 6 ed Ausueq iv ON JEH UOJSId Oso 16 AYIA e007 ON JEUSS JES SSE N vu Ko ezo Ey y you y OUI ue q OUD or nn 1 eunyesoduie p o dx3a CO 91eq SLINN HSI19N3 LASHSMYOM NOILVINO WS FJUNSSF44 AONVS JUNSSFU4d NOLSId jenueyy si sn S8rp VASNA LL V N W ed ed W N W 6J ed 6y 6 16 x 3unssaud 9X DY DOOOL bs Ausueq ssey x 6 UWNION J pulew y q 0 nel umip u d TVNINON 1809 dus sossey ae Oo 9 ed JJO UW Yd OINSSBJg SOUBIOJOY ed edyy cq by sseyy ose L ed edW q w KoueAong 9 Apae W Os EZ ye v Ey Uu DY uuo B ed Aysueq iy ON EINES uo sid 098S W 16 Apae e007 ON JEWS 18S SSEW u 0 Z 3 9 19 v ul u BOUBJOJJIG ue d BOUSIBJOY I 1 eunyesodwe p o dx3a a1eq SLINN IS LAAHSMYOM NOILVINO WS AYNSSAYd AONVS JUNSSF4d NOLSId jenue
33. D IS IN LIEU OF ALL OTHER WARRANTIES EXPRESS OR IMPLIED INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE FLUKE SHALL NOT BE LIABLE FOR ANY SPECIAL INDIRECT INCIDENTAL OR CONSEQUENTIAL DAMAGES OR LOSSES INCLUDING LOSS OF DATA ARISING FROM ANY CAUSE OR THEORY Since some countries or states do not allow limitation of the term of an implied warranty or exclusion or limitation of incidental or consequential damages the limitations and exclusions of this warranty may not apply to every buyer If any provision of this Warranty is held invalid or unenforceable by a court or other decision maker of competent jurisdiction such holding will not affect the validity or enforceability of any other provision Fluke Corporation Fluke Europe B V P O Box 9090 P O Box 1186 Everett WA 98206 9090 5602 BD Eindhoven U S A The Netherlands 11 99 To register your product online visit register fluke com Table of Contents Chapter Title 1 Introduction and Specifications ji OLOTE NT D a PPE ETA EEE EE A cats suposa quis How to Contact Plake uuu u Uu L uu u uuu usa massaspipaaqusssaqasqipaphashiasapasqspap a un pas Sol UA OLIV il O u u luna spushustiususwustyiqasssssipaakiyaqiasusyayqaqqiyiqasssapa Symbols Used in this Manual General SS 1 AN OIN er ers Pisto
34. DE Cylinder u uu u u uuu u n awaspa Buaya AE 22 Re FEntrant Cylindep kuu u ua a eran N ranar qm kkayaskkawayaqakaayastasqakashhiqa 2 3 Controlled Clearance Cylinder seem 3 1 Front View RUSKA 2485 950 similar to RUSKA 2485 930 3 2 Rear View RUSKA 2485 950 similar to RUSKA 2485 930 3 3 Right Side View RUSKA 2485 950 similar to RUSKA 2485 930 3 4 Top View RUSKA 2485 950 similar to RUSKA 2485 930 3 5 Right Side View RUSKA 2485 950 without Cover 3 6 Top View RUSKA 2485 950 without Cover j Mass SEN BOK uuu u uuu a aE 3 8 Instrument Platform with Partial Mass Set Loaded RUSKA 2485 930 and RUSKA 2463D 05 ee reinen 3 9 Rear View RUSKA 2485 903 and RUSKA 2485 935 3 10 Section View of Pressure Column Extended Range Column and Extended Range P C RUSKA 2485 950 3 11 Section View of Column Assembly RUSKA 2485 930 or RUSKA 2485 950 wib Low Range PC een 4 1 Lo and Mid Press Plumping Schematic 4 2 Hi Pressure Plumbing Schematie un aa 4 3 Voltage Selector SWIIeh nee ee 4 4 Test Port Manifold and Adapters
35. IN SPANNER 2 DIAMETER 1 00 EACH W 1 4 PIN 94 618 WRENCH PIN SPANNER 2 25 DIAMETER 1 00 EACH W 1 4 PIN 94 628 WRENCH OPEN END 1 4 X 5 16 1 00 EACH CE Cores WRENCH open enose ximo faoc Cors WRENCH OPEWEND vexane faoc 94 637 WRENCH OPEN END 7 16 X 1 2 OEC fo orsa wnenon rowers froen Coreas WRENCH openen xro ins Table B 3 Setup Kit 2485 203 for RUSKA 2485 935 a Eu s RTD PRT HOLDER 1 8 NPT X 3 16 OEC fo 265 PISTON CYLNER GLEAWNGKT nenn 25102001 LOW RANGE CINDER creanme Toor tE eos uwa T _______ 2485 203 002 P C ASSEMBLY TOOL 1 00 EACH FOR QUICK CHANGE P C Be 920 Ba BLOCK 1 DT I 100EACH 2485 935 007 935 007 BAKPRNG RING 1 00 100 EACH PRESSURE COLUMN 2485 KIT 001 ADAPTER KIT 1 00 EACH FOR AUXILIARY BLOCK 2246 216 FUSE 1 AMP SLOW BLOW SIZE 3AB 1 AMP SLOW BLOW SIZE 3AB 2 00 200EACH 54 603 008 O RING VITON 3 16 I D X 1 16 CROSS 10 00 EACH 40 K PSI P C oor 60 DUROMETER 854 700 437 700 437 DRIVE BELT DRIVE BELT 2485 0 _ 1 00 100EACH FOR ROTATION SLEEVE ROTATION SLEEVE 594 703 117 O RING VITON 13 16 X 3 32 CROSS 2 00 EACH FOR P Cs OTHER THAN 40 aoe mms Tg 12 7233 000 SEAL 1 4 X 1 2 POLYPAK 1 4 X 1 2 POLYPAK 4 00 400EACH FOR CONNECTOR BLOCK CONNECTOR BLOCK B 2 Setup Kit Bills of Material Setup Kit 2485 202 for RUSKA 2485 930 950 Table B 4 Setup Kit 2485 203 for RUSKA 2485 935 continued
36. Instrument Pressure Range 2485 930 0 5 to 1 375 bar 7 25 to 20 000 psi 2485 950 0 5 to 5 000 bar 7 25 to 72 500 psi gauge mode pressures referenced to ambient atmospheric pressure Safety Test Pressure 1 5 times the system working pressure for low pressure system 1 25 times the system working pressure for high pressure system Pressure Media Spinesstic 22 oil S22 Dioctyl Sebacate oil DOS Introduction and Specifications 1 Piston Cylinder Specifications Accuracy Class Pressure accuracy to 0 0025 reading from 6 of full scale to full scale and 0 0003 of full scale below 6 traceable to U S National Institute of Standards and Technology Instrument Platform Dimensions Height 50 8 cm 20 in including mass stack 72 cm 20 in with high pressure extension Width 50 8 cm 20 in Depth 35 6 cm 14 in excluding hand pump Handle Weight 40 kg Electrical Requirements 115 or 230 vac 50 or 60 Hz switchable Temperature Range Operation 18 C to 28 C Storage 20 C to 50 C when thermometer is removed Humidity Range Operation 20 to 75 Storage 0 to 90 Piston Cylinder Specifications Sensitivity Threshold 0 0001 reading 1 ppm Repeatability 0 0003 reading 3 ppm Reproducibility 0 0006 reading per year 6 ppm Piston Cylinder Material Cemented Tungsten Carbide 6 Cobalt Thermal Coefficient 9 1 x 10 in in deg C 9 1 ppm per deg C Cylinder Configuration Simple Minimal Mounting Stress
37. L S WLLL Z Z Z Z A Ms EXTERNAL RESERVOIR PORT Don J f f f f i gt RESERVOIR ON RIGHT AT TOP PRESSURE INTENSIFIER RATIO 1 4 8 I T ur D Z ZN TOP BACK VALVE A Z22222 PRESSURE ON RIGHT AT BOTTOM INTENSIFIER TOP FRONT VALVE C RUPTURE Ba ISK PRESSURE INDICATOR 22 000 PSI DIAL GAGE 15 000 72 600 gmd18 eps Figure 4 2 Hi Pressure Plumbing Schematic Note Whenever operating the valves use only the minimum torque required to close the valve and open the valve very slowly when there is a differential pressure across the valve 4 16 RUSKA 2485 System Operation Valve Operating Procedure RUSKA 2485 950 Recharging the Hand Pump While at Atmosphere With reservoir valve A and pressure valve B open rotate the hand pump spindle counter clockwise until the pump position indicator approaches the counter clockwise travel limit Rotate the hand pump spindle clockwise approximately one quarter turn to remove any spindle nut backlash Generating Pressures to 20 000 PSI 1400 Bar Pressurizing the System Open valve A C and D Close pressure valve B and rotate the hand pump spindle clockwise If the pressure system is sealed and no air is trapped n the hydraulic system the pressure should begin to increase within one quarter turn of the hand pump spindle Refer to Chapter 5 Troubleshooting Common Problems
38. PN 3974967 December 2010 Calibration RUSKA 2485 Hydraulic Piston Gauge Users Manual 2010 Fluke Corporation All rights reserved Printed in USA Specifications are subject to change without notice All product names are trademarks of their respective companies LIMITED WARRANTY AND LIMITATION OF LIABILITY Each Fluke product is warranted to be free from defects in material and workmanship under normal use and service The warranty period is one year and begins on the date of shipment Parts product repairs and services are warranted for 90 days This warranty extends only to the original buyer or end user customer of a Fluke authorized reseller and does not apply to fuses disposable batteries or to any product which in Fluke s opinion has been misused altered neglected contaminated or damaged by accident or abnormal conditions of operation or handling Fluke warrants that software will operate substantially in accordance with its functional specifications for 90 days and that it has been properly recorded on non defective media Fluke does not warrant that software will be error free or operate without interruption Fluke authorized resellers shall extend this warranty on new and unused products to end user customers only but have no authority to extend a greater or different warranty on behalf of Fluke Warranty support is available only if product is purchased through a Fluke authorized sales outlet or Buyer has paid t
39. Part Number Description ee of Measure 72 43 SEAL 625 OD X 375 ID POLYPAK 4 00 EACH FOR HAND PUMP AND COLUMN 86 802 TUBING CLEAR PLASTIC 3 8 OD X 5 00 FT WASTE MEDIA DRAIN LINE ane waqsa W X 1 4 ID 91 308 398 DISK SPRING WASHER 505 X 1 0 SPRING WASHER 505 X 1 0 2 00 200EACH FOR 40K FORAOKOCPCHOLDER HOLDER er 607 WRENCH HEX KEY 1 8 1 00 EACH a DIAMETER W 1 4 PIN e l DIAMETER oer ss 1 4 PIN 94 628 628 WRENCH OPEN END 1 4 X 5 16 OPEN END 1 4 X 5 16 1 00 100EACH oS O ors Twmenon oremenonexum nenn 94 637 WRENCH OPEN END 7 16 X 1 2 OEC fo orsa wRENGH owsa men _ ors WRENOH oPeNeND acre Jroen o OO 99189 RUSKA GLOVES 1 00 PAIR FOR HANDLING MASSES 99190 008 PIN WRENCH STRAIGHT 14 roeas B 3 2485 Users Manual B 4
40. Procedure RUSKA 2485 930 See Plumbing Schematic Figure 4 1 This section describes the proper valve operating procedures for the various functions of the RUSKA 2485 930 deadweight gauge instrument platform N Caution The operator of any pressurized equipment must always be aware of the condition and status of the equipment to avoid the risk of damage and personal injury Recharging the Hand Pump at Atmospheric Pressure With reservoir valve A open rotate the hand pump spindle counter clockwise until the pump position indicator approaches the counter clockwise travel limit Rotate the hand pump spindle clockwise approximately one quarter turn to remove the spindle nut backlash Pressurizing the System 4 13 RUSKA 2485 Users Manual Close reservoir valve A and rotate the hand pump spindle clockwise If the pressure system is sealed and no air is trapped in the hydraulic system the pressure should begin to increase within one quarter turn of the hand pump spindle Refer to Chapter 5 Troubleshooting Common Problems for troubleshooting Adjusting Float Position l As the pressure approaches that required to float the piston reduce the rate of hand pump spindle rotation and slowly approach the proper float position If the float position or system pressure is too high rotate the hand pump spindle counter clockwise until the proper pressure or float position is obtained Rotate the hand pump spindle an additional one q
41. USKA 2485 System Operation A Test Port Manifold Connections Mass Set Although not essential it is recommended that the masses be loaded and stored in sequence according to the sequence number marked on each piece When placing the masses into the storage boxes fill box 5 first then 4 and 3 etc Place the highest sequence number 5 kilogram mass at the rear of the box moving toward the front with the lower numbered masses The 3 kilogram mass is stored in the front of the box 5 The 2 kilogram through 0 2 kilogram masses the hanger mass sequence number 01 and the piston cylinder assemblies are stored in box 1 Test Port Manifold Connections N Caution All pressure must be removed from the system prior to disconnecting the test port manifold from the auxiliary pressure housing The test port manifold should be disconnected from the auxiliary pressure housing before attaching a device or instrument to be tested Remove all pressure from the system and close the appropriate valve to isolate the reservoir Refer to Chapter 4 Valve Operating Procedure for RUSKA 2485 930 and Valve Operating Procedure for RUSKA 2485 950 for the specific valve operating sequence Loosen the test port manifold retaining nut until it 1s free of the threads on the auxiliary pressure housing Turn the hand pump clockwise approximately 3 or 4 turns then carefully lift the test port manifold off of the auxiliary pressure housing Inspect the seal on the lo
42. age container and place it in the appropriate storage location Installing a Piston Cylinder or Shipping Plug RUSKA 2485 930 and RUSKA 2485 950 Before installing a piston cylinder assembly or shipping plug into the pressure housing inspect the o ring cylinder seal If the o ring is worn or leaks when pressurized tt should be replaced before continuing Carefully locate the o ring in the appropriate sealing groove Place a clean low lint wiper on the workbench Carefully remove the top of the piston cylinder storage container and set it aside Using the appropriate insulation between piston cylinder components and fingers place the forefinger directly above the piston and empty any excess oil out of the storage container Slide the piston cylinder assembly out of the container and set it upright on the clean wipes Turn the hand pump spindle to adjust the oil level in the pressure housing to about the top of the o ring cylinder seal Firmly grasp the top edge of the cylinder with the left hand Place the forefinger of the left hand on the top edge of the piston and apply a slight lateral force to the piston to prevent the piston from exiting the bottom of the cylinder when it is moved to the pressure housing 4 8 RUSKA 2485 System Operation Operating Procedure for the RUSKA 2485 Deadweight Gauge Carefully insert the bottom of the piston cylinder assembly into the pressure housing Open the appropriate valve to activate the reservoir W
43. aks are present in the system as would be indicated by an abnormally high sink rate at the end of the thermal stabilization period can reliable pressure measurements be made Accuracy and Traceability The validity of a measurement made using a deadweight gauge or any other device is influenced by numerous factors other than basic performance parameters such as linearity repeatability and hysteresis to list a few Typically the largest contribution to the estimate of total uncertainty the bounds within which the true value lies often referred to as accuracy is the uncertainty assigned to the standard or system used to provide traceability As comparative measurements are performed at each level in a measurement chain used to transfer the knowledge about a reference device to a test device the potential for error increases These additional errors generally but not exclusively are the result of performances parameters such as those stated above Significant additional contributions may be the result of environmental factors operator intervention and human error These are the most difficult to assess and eliminate yet may contribute the greatest errors To take full advantage of the performance characteristics of precision deadweight gauges which require substantial operator manipulation and mathematical computation appropriate precautions must be taken to minimize the risk of gross errors and to reduce the miscellaneous influences
44. alue from the remainder which now results in another new remainder mass value Calculations A Equation A 4 Air Density Continue this process until the remainder which now results in another new remainder mass value Continue this process until the remainder is smaller than the smallest available mass from the mass set At every step record the selected mass its mass ID number into Column 10 O Column 11 the remainder from Column 10 is the mass that must be placed on the piston pressure gauge to complete the mass needed to set the desired pressure This remainder recorded in Column 11 is realized with the Trim Mass set provided with all RUSKA Mass Sets The RUSKA supplied Trim Mass Sets are defined as Class 3 Type 1 per ASTM E617 formerly Class SI per NBS Cir 547 These fractional masses should also be used to adjust the mass load for piston pressure gauge operating temperatures that differ from the expected temperature t These fractional masses could also be used to adjust the mass load for the piston pressure gauge if the reference plane of the device being calibrated 1s at a different elevation than planned in the original head correction P Inthe English system the remainder can be recorded in pounds in Column 11 and in grams in Column 12 The conversion factor to convert pound mass to grams is 453 59237 g lbm Q Column 13 is used to calculate a temperature coefficient This temperature coefficient is use
45. assed do not decrease the pressure Rather slowly and carefully loosen select fittings one at a time to release the oil As the oil is released maintain the pressure using the hand pump Continue until a significant volume of oil has passed through each of the bleed points usually a full stroke of the hand pump is required Release the pressure recharge the hand pump and repeat the test Pressure Leaks 5 6 Eventually every hydraulic system develops a leak This section includes information useful in isolating such leaks in the RUSKA 2485 deadweight gauge The first indication of a leak in a pressurized system is that the pressure decreases with time Another measure of leaks in a pressurized deadweight gauge system is that the piston cylinder sink rate is excessive If the sink rate is abnormally fast there may be a leak in the system If the system has only recently been pressurized decreasing pressure and an abnormally fast sink rate are to be expected The act of pressurization results n heating of the pressure medium As the heat dissipates into the system the pressure decreases The piston cylinder acting as a regulator adjusts the volume of the system attempting to maintain the pressure resulting in the abnormal sink rate This adiabatic effect must be allowed to dissipate before troubleshooting all but the largest of leaks Figures 4 1 and 4 2 are plumbing schematics that can be used to identify the appropriate valves to i
46. asurement Measurements amp Data Home Study Course No 17 Measurements and Data September October 1969 9 Tate D R Gravity Measurements and the Standards Laboratory National Bureau of Standards Technical Note No 491 1969 10 Heydemann and Welch Chapter 4 Part 3 Pure and Applied Chemistry Butterworths 11 12 Piston Pressure Gauge Bibliography Kirk K Mosher Ruska Instrument Corporation The Traceability Chain of the Piston Pressure Gauge to NIST presented at the Canadian National Conference of Standards Laboratories 1991 Ken Kolb Ruska Instrument Corporation Reduced Uncertainty and Improved Reliability for the Pneumatic Piston Pressure Gauge Through Statistical Process Control published in the Proceedings for the Annual Measurement Science Conference 1991 2 2 13 RUSKA 2485 Users Manual Chapter 3 Technical Description Instrument Overview The RUSKA 2485 deadweight gauge is a fully integrated high precision high accuracy piston pressure gauge system used as a standard to calibrate pressure transducers and bourdon tube gauges and as a precise pressure balance to accurately measure maintain and control pressures up to 20 000 psi 1400 bar in the low pressure version RUSKA 2485 930 40 000 psi 2800 bar in the medium pressure version RUSKA 2485 935 and up to 72 500 psi 5000 bar in the high pressure version RUSKA 2485 950 The RUSKA 2485 incorporates all the necessary componen
47. ation 2 Fully recharge the hand pump and generate approximately 2 000 psi 140 bar as per Chapter 4 Valve Operating Procedure for RUSKA 2485 930 RUSKA 2485 935 8 for RUSKA 2485 930 or Chapter 4 Valve Operating Procedure for RUSKA 2485 950 3 Without rotating the hand pump spindle remove the handles from the hand pump This will ensure that no air becomes trapped in the system during shipment or storage N Warning If a liquid in glass thermometer is being used remove it from the base and package it separately for shipment or storage N Warning The maximum pressure rating for the low pressure shipping plug is 20 000 psi 1400 bar Do not exceed this pressure with the low pressure shipping plug installed 4 Rotate the reservoir source valve on the rear of the instrument platform ONE QUARTER TURN 5 Remove the oil from the internal reservoir down to a level flush with the fitting at the bottom of the reservoir 6 Wipe any excess oil from the base plate and pressure housing Remove clean and store the reservoir cover and the oil drain cups Place a clean dry paper wiper in the internal reservoir to prevent contamination of the reservoir 9 Place a small strip of soft open cell foam approximately 1 cm x 1 cm x 10 cm around the bottom of the mass loading table assembly between the table top and the retaining nut This will prevent the mass loading table assembly from vibrating during transport Valve Operating
48. ation of the effective area of the assembly High performance piston pressure gauges may be constructed using simple or re entrant cylinders Determination of the distortion coefficients and effective area of such gauges may be made by direct comparison with a controlled clearance gauge Although elastic distortion affects all types of piston pressure gauges the magnitude may be small enough that it can be ignored Elastic Distortion of the Piston Cylinder Assembly As the pressure is increased within a piston pressure gauge the resulting stress produces a temporary and reversible deformation of the piston cylinder components The result is a change in the effective area of the piston cylinder assembly If the change in the area is a linear function of the applied pressure the relationship may be described by the equality A A 1 bp where A Effective area at pressure p A Effective area of the piston cylinder assembly at zero pressure b Coefficient of elastic distortion the fractional change in area per unit of pressure and p Nominal system pressure acting on the piston cylinder assembly For higher pressure instruments the pressure effect may be non linear and is commonly expressed by the equality 4 A 1 bp b p 2 3 RUSKA 2485 Users Manual where Effective area at pressure p Effective area of the piston cylinder assembly at zero pressure ad Coefficient of elastic distortion as a
49. be relatively rapid and may be excessive This is the same indication as when the pressure system is leaking except that with time a leak free system will attain equilibrium and the sink rate will return to normal A rapid decrease in pressure will result in an abnormally slow sink rate This thermal effect can be so great that the piston will actually rise in the cylinder until the system approaches equilibrium Any abnormal sink rate is an indication of instability in the pressure or leaks in the system During the thermal stabilization period adjust the hand pump as necessary to maintain the float position of the piston In addition the temperature of the piston may change slightly during the stabilization period and any fine load adjustment applied in Chapter 4 Fine Load Adjustment to correct for thermal effects should be re evaluated just prior to the final pressure measurement Execute Pressure Measurement Once the appropriate load is applied the thermal effects have adequately diminished and the piston is rotating at the mid float position a pressure measurement can be made with confidence RUSKA 2485 Users Manual Next Pressure Once a pressure measurement is complete carefully stop the rotation of the mass stack Repeat the steps in Chapter 4 Load Other Masses through section Execute Pressure Measurement for each desired pressure When changing the deadweight gauge pressure to a higher level first increase the load the
50. blies under normal use However the risk of damage or breakage is greatly increased with misuse and abuse The following pressurization routine Chapter 4 Install the Hanger Mass through to Assess Stability will minimize the risk of damage to the precision finish of the piston and cylinder assemblies A Warning Any SUDDEN shift increase or decrease in the load on the piston can result in permanent damage to the piston If when loading and unloading the masses on the deadweight gauge CAREFUL consideration is given to prevent damage to the precision finish of the masses adequate protection will be provided for the piston Install the Hanger Mass With ONLY the hanger mass sequence 01 installed on the mass loading table increase the pressure until the piston is floating Note The approximate or nominal pressure generated using the RUSKA 2485 deadweight gauge can be computed from the pressure unit increment designator marked on the tare compensator disk and the nominal mass designation marked on the masses Load Other Masses 1 Carefully load the next required mass onto the hanger mass When loading the masses onto the deadweight gauge verify that they are in the proper sequence and align the identification markings for quick and easy viewing once installed 2 Once anew mass load forces the piston to the bottom of travel this may not occur with larger diameter pistons or small changes in the load carefully rotate the load s
51. c valve operating procedures which are different for the two versions of the instrument are detailed in Chapter 4 Valve Operation Procedure for RUSKA 2485 930 and Valve Operating Procedure for RUSKA 2485 950 Once the operator becomes familiar with the valving techniques for a particular version the following steps should be followed to safely and efficiently generate the desired pressures Establishing Atmospheric Pressure Verify that the instrument is at atmospheric pressure as indicated by the pressure monitor and that the reservoir is on line by actuating the appropriate valves according to Chapter 4 Valve Operation Procedure for RUSKA 2485 930 and Valve Operating Procedure for RUSKA 2485 950 When using the RUSKA 2485 deadweight gauge to calibrate a transducer or Bourdon tube gauge zero pressure is often required for the initial and final observations With the appropriate valves open to the reservoir refer to Chapter 4 Valve Operation Procedure for RUSKA 2485 930 RUSKA 2485 935 and Valve Operating Procedure for RUSKA 2485 950 atmospheric pressure 1s allowed to act on the sensing element through the reservoir which acts as a monometer If the reference plane of the instrument under evaluation is not at the same height as the fluid in the reservoir there s a small pressure exerted on the instrument under evaluation The magnitude of this pressure is equal to the difference in height between the reservoir level and the reference
52. cated on the pressure monitor 7 Carefully rotate the hand pump spindle counter clockwise until the pressure monitor indicates between zero and 500 psi 35 bar and open pressure valve B 8 Continue rotating the hand pump spindle counter clockwise until the pump position indicator approaches the counter clockwise travel limit 9 Rotate the hand pump spindle clockwise one quarter turn and close reservoir valve A and intensifier valve C 10 Carefully rotate the hand pump spindle clockwise to generate pressure 11 Once the pressure monitor indicates the same pressure noted earlier in this section slowly open system valve D Discharging the Intensifier While at Pressure 4 20 If the intensifier was recharged while at pressure it 1s likely that during depressurization the intensifier will reach the return stroke limit while the system remains pressurized The intensifier may be discharged while the system remains at pressure to allow further depressurization of the system The indication to the operator that the intensifier plunger has reached the return stroke limit is that the pressure monitor will indicate a sudden increase in the rate of depressurization The pressure at which this occurs is important to the following procedure To discharge the intensifier while the system is at pressure 1 Note the pump pressure as described above except that the hand pump spindle must be rotated clockwise until the intensifier again begins
53. ce due to the air surrounding the masses as a function of the density of the objects and the ambient air as follows F F 1 D D where F Resultant Vertical Force F Original Vertical Force D Air Density nominally 0 0012 g cm and D Mass Reference Density For most piston gauges the mass values are usually reported in units of apparent mass versus brass standards or apparent mass versus stainless steel and True Mass If the load on a piston is comprised of various materials with various densities buoyancy corrections using True Mass values would be computed individually for each type of material A single correction to the entire load however can be made by using apparent mass values and substituting the reference density 8 4 g cm for apparent mass versus brass and typically 8 0 g cm for apparent mass versus stainless steel for the true density in the buoyancy correction As with the piston cylinder assembly temperature affects the dimensions of the masses These dimensional changes result in volume changes and hence buoyancy changes The nominal volumetric thermal coefficient for a typical steel used in piston gauge masses 1s approximately 45 x 10 per degrees Celsius has only a very small effect and is typically ignored in piston pressure gauge applications Changes in air density resulting from barometric temperature and relative humidity changes can be significant to piston pressure gauge meas
54. ce of the deadweight gauge system including the instrument platform the mass set and the piston cylinder assemblies Although the maintenance requirements for this system are minimal those that relate to the routine handling are critical to the longevity and reliability of the instrument Instrument Platform Maintenance The instrument platform requires little maintenance Functional integrity and esthetic preservation are primarily the result of careful manipulation of the instrument Several components however may require occasional verification adjustment or repair Oil Drain Hose Route the oil drain hose to an appropriate container Instrument Platform Cleaning Occasionally oil or other contamination will accumulate in various locations on the instrument platform Wipe any contamination and accumulated oil from the top and bottom surfaces of the instrument platform The instrument cover may require removal to adequately clean the instrument platform Refer to Chapter 5 Instrument Cover Removal and Replacement for instructions on removing the instrument cover RUSKA 2485 Users Manual Level Vial Adjustment Optimum performance and reliability of the pressure measurements made using a deadweight gauge rely on the piston axis being vertical When properly adjusted the level vial mounted to the instrument platform is a simple and reliable reference Proper adjustment of the level vial should be verified periodically If the mai
55. d pressure created by the pressure medium and the difference in height between the piston pressure gauge and the device under test A A minimum of six significant figures must be used in all calculations involving reported constants masses etc The manufacturer s claims for accuracy assume the local gravity to be known to at least six significant figures B When the piston pressure gauge is used as a standard of pressure it is convenient to perform the pressure to mass calculations in advance of operating the standard Since the piston gauge temperature fluctuates while it is operated a confusing point in the procedure is the necessity for the temperature of the gauge to be predicted prior to operation This expected temperature however is used to allow the pressure calculations to be performed Once the piston pressure gauge is floating at the intended pressure a final temperature observation is made and then trim masses are loaded onto the piston gauge to correct for any temperature variations that exist between the expected and the actual temperatures The final column in the worksheet is used to calculate the temperature coefficient which defines the amount of trim that is required to correct for this temperature change It is usually prudent to select an expected temperature t which is lower than any temperature that will be experienced This is so that the operator can always add mass to correct for the actual temperature A
56. d to correct for any piston temperature variation from the expected temperature value that was used to calculate the mass loads for the various pressure points in the worksheet See item B above Equation A 4 Air Density Air Density P in units of g cm is calculated as follows D 0 0004646 x P 4990221 6 x U x e5565 9 273 15 2 where P Barometric Pressure mmHg t Air Temperature C U Relative Humidity ARH Nitrogen Density English Units 0 to 1000 PSIG To calculate the density of Nitrogen at pressures from 0 psig to 1000 psig use the following equation DENSITY lbm in 2 826 x 10 x P where P PRESSURE in psi absolute if P is in gauge convert it to an absolute value by adding barometric pressure e g P 14 7 Nitrogen Density English Units 1 000 to 15 000 PSIG To calculate the density of Nitrogen at pressures from 1 000 psig to 15 000 use the following equation DENSITY Ibm in 2 37465 x 10 2 74396 10 P 9 46069 x 10 1 P where P PRESSURE in psi absolute if P is in gauge convert it to an absolute value A 5 RUSKA 2485 Users Manual by adding barometric pressure e g P 14 7 Nitrogen Density SI Units 0 to 6 9 MPa To calculate the density of Nitrogen at pressures from 0 01 MPa gauge to 6 9 MPa use the following equation DENSITY kg m 1 1347 E 05 x P where P PRESSURE in Pa absolute if P is in gauge convert i
57. dding mass is generally more convenient than subtracting mass from the planned loading arrangement Standard metric trim mass set is entirely suitable for this purpose A 1 RUSKA 2485 Users Manual All of the calculations will be performed to this expected temperature t A final trim would be calculated to adjust the piston gauge to the temperature of the piston at the time of the actual measurement This correction is calculated in the last column of the worksheet This column represents the number of grams to be added to the stack of masses for a difference in the actual temperature from the expected temperature t The final trim is computed using the following formula and loaded onto the piston gauge Temp Coef x actual temperature exp ected temperature The Symbol A represents the effective area of the piston and its cylinder at atmospheric pressure when operating at temperature t it is obtained from the relation A t A o3 1 C At O A 3 reported area of the piston at 23 degrees Celsius c thermal coefficient of superficial expansion t 23 At C Gravity and Buoyancy Correction When the masses are applied to the piston in the presence of the buoyant atmosphere buoyancy corrections are necessary and are combined with gravity corrections For convenience the combined correction K or K is applied as a multiplier with the result indicating the quantity of apparent mass tha
58. der Place the piston cylinder assembly into the storage container cover with clean deadweight gauge oil and secure the top of the container Alternate Piston Cylinder Cleaning Method If soap and water are not available the piston cylinder assemblies may be cleaned with a mild solvent such as high grain alcohol or acetone provided no residues remain on the parts prior to assembly This process may not yield as consistent results as cleaning with soap and water Mass Set Cleaning 5 4 It is recommended that the deadweight gauge masses be handled using clean gloves such as number 99189 included in the 2485 202 or 2485 203 set up kit Should the masses become contaminated they may be cleaned using a mild solvent such as high grain alcohol or using soap and water provided that they are thoroughly dried afterwards Maintenance and Troubleshooting Troubleshooting Common Problems Troubleshooting Common Problems Air Trapped in the System Air trapped in a hydraulic system can be more than an annoyance When a substantial amount of air is trapped in the system the system may become virtually inoperable The high compressibility of the air prevents significant pressure from building in the system until the air has been adequately compressed This condition may use up a substantial portion of the available hand pump travel A system with little or no trapped air however will require only one quarter turn of the hand pump spindle before
59. dle clockwise and observe the pressure monitor for 11 an indication Note Pressurization of the instrument to more than about 500 psi 35 bar is unnecessary at this point If more than one quarter turn is required to obtain a pressure reading some amount of air is likely trapped in the hydraulic system and should be removed prior to continuing Instructions for removal of air from the system are included in Chapter 5 Maintenance and Troubleshooting If a pressure change is noted within about one half rotation of the hand pump spindle the time required to remove this air may be a greater inconvenience than operating the system in such a condition A small amount of air trapped in the system will gradually dissipate and work its way out of the system during normal operation Repeat steps 4 and 5 12 Verify that the hydraulic pressure has been removed from the system When making connections to the pressure ports or test port manifold or when installing a piston cylinder assembly Reservoir Valve A or Pressure Valve B depending on the model version low pressure RUSKA 2485 930 or high pressure RUSKA 2485 950 must be closed Instructions for each of these operations and for general pressure generation for each version of the RUSKA 2485 are described in the following sections 13 Install the mirror block assembly part number 2485 920 on the front left corner of the instrument platform as shown n Figures 3 1 and 3 4 R
60. e C Remove the tubing from the reservoir end of the safety head Figure 5 1 Remove the safety head from the hand pump housing Remove the torque nut from the main body and extract the spent rupture disk Insert the new rupture disk into the body replace the hold down ring and torque nut and torque to between 100 and 110 foot pounds Fill the end of the safety head assembly opposite the reservoir plumbing with clean deadweight gauge oil and install the safety head assembly into the hand pump housing but do not tighten Slowly rotate the hand pump spindle clockwise until oil seeps from the safety head mounting port see note below Carefully tighten the safety head assembly to the hand pump housing and replace the reservoir tubing on the opposite end of the safety head assembly Refer to Chapter 5 Troubleshooting Common Problems for troubleshooting leaks and air trapped in the system Note If the hand pump does not have enough travel to force oil through the safety head port temporarily tighten the safety head assembly and recharge the hand pump per Chapter 4 Valve Operating Procedure for RUSKA 2485 930 RUSKA 2485 935 or Valve Operating Procedure for RUSKA 2485 950 Loosen the safety from the hand pump housing and rotate the hand pump spindle to force oil through the safety head port Instrument Cover Removal and Replacement Several aspects of the instrument platform maintenance require removal of the instrument cover This s
61. e conversion factor Aa Effective area corrected to working temperature R Reference pressure absolute mode typically 100 mTorr and H Head pressure Conditions Favorable For a Measurement 2 10 Precision pressure measurements using a deadweight gauge can only be made when all miscellaneous disturbances such as vibration air drafts and personnel traffic have been minimized or eliminated Further if an operator is inadequately trained in the proper operation of the equipment or whose judgment is impaired by distractions or other influences there is discernible risk of personal injury and damage of delicate instrumentation When operating a precision deadweight piston gauge one concern is the amount of time available to make a measurement The major influence on the time available to make a measurement is the amount of time the piston remains in the region near the calibrated mid float position This float time is directly dependent on the sink rate of the piston the rate at which the piston descends into the cylinder displacing the fluid that leaks through the annular clearance provided to lubricate the piston There are several conditions of normal operation of a deadweight gauge that temporarily bias the sink rate When a volume of fluid gas or oil is compressed a sudden rise occurs in the temperature of the fluid As this heat dissipates into the surrounding containment the temperature of the fluid is reduced and the
62. e of a deadweight gauge requires a functional piston cylinder assembly The piston cylinder assembly must be clean to operate properly and preclude permanent damage Typically hydraulic piston cylinder assemblies once clean and when handled properly will not likely require periodic cleaning Deliberate and careful handling and proper storage of a piston cylinder assembly in the storage container or main pressure housing will prolong the life of the assembly and help to prevent contamination Should a piston cylinder become contaminated however it must be cleaned before resuming operation The piston cylinder cleaning procedure is as follows l Fold or twist several light duty wipers Kimberly Clark Type 900S Kimwipes recommended as shown in Figures 5 2 and 5 3 for removing excess oil from the piston and cylinder and for drying parts later in the procedure Wipe the excess oil from the parts Wetting the wipers with a mild solvent such as high grain alcohol or acetone may be helpful 2 Using a clean bottle brush part number 7 682 for the low range cylinder and medium duty paper wipers for other parts thoroughly scrub the piston and cylinder with soap Cashmere Bouquet and lukewarm water Thoroughly rinse the parts and quickly dry with the folded or twisted wipers 3 Set the parts aside for 15 minutes prior to assembly Coat the bottom of the piston in clean deadweight gauge oil and carefully insert the piston into the cylin
63. e of a laboratory mass set with denominations from 100 grams to 10 milligrams This load adjustment is placed directly on the mass loading table and should be removed prior to changing the load to generate a subsequent pressure Adjust Float Position Once the desired load is applied to the piston use the hand pump to adjust the pressure so that the piston is slightly above the mid float position As the system stabilizes the normal sink rate of the piston will carry it through mid float The mid float position can be measured manually or electronically When the bottom edge of the hanger mass sequence 01 bisects the float position line located just above the pulley on the drive sleeve the piston is at mid float The position of the hanger mass can be observed in the float position mirror block assembly mounted on the instrument platform as shown in Figures 3 1 and 3 4 A more accurate measurement of float position can be made using the electronic float position option Assess Stability The operator must make a judgment as to the stability of the pressure system and allow adequate time for the thermal effects of pressurization to diminish For high precision pressure measurements the stabilization period may be in excess of 20 minutes One indication of the relative stability of the system is the rate at which the piston descends into the cylinder In a system that has just been pressurized the rate of piston descent or sink rate will
64. e pump for generating hydraulic pressure The position of the hand pump plunger and the amount of remaining stroke is indicated by the relative position of the pump position indicator located in the opening in the top of the instrument cover Pump Handles The instrument is supplied with four pump handles for optimum control of the pump The handles can be secured to the pump spindle nut by gentle tightening using a wrench on the milled flats near the spindle nut end of each handle Pump Spindle Cover The pump spindle cover prevents contact with the spindle lubrication Pump Lubrication Port Cover The pump lubrication port cover prevents contamination from entering the pump lubrication port Air Bleed Screw Cover RUSKA 2485 930 amp RUSKA 2485 950 The air bleed screw cover prevents contamination from entering the instrument through the air bleed screw access port in the top of the instrument cover Safety Head And Rupture Disk Assembly To prevent over pressure of the hand pump assembly a safety head and rupture disk assembly is installed into a special port in the side of the pump housing Should the pump pressure exceed the rupture disk rating the pressure will be vented to the internal reservoir thereby preventing damage to the instrument or the operator A replacement rupture disk must be installed prior to further operation Refer to Chapter 5 for specific instruments on replacing the rupture disk Technical Description 3
65. e required on piston as found in Column 8 multiplier which was obtained by previous equation When the masses are applied to the piston in an evacuated bell jar the above equations for K and K can still be used In this situation the density of air 9 will be zero which will cause the buoyancy portion of the equation to become 1 Also the results will indicate the quantity of true mass not apparent mass that must be applied to the piston D Column 1 F is the desired pressure at the reference plane of the device being calibrated E Column 2 is the mass density of the pressure medium being used in the piston pressure gauge system For hydraulic piston pressure gauges this number can be considered constant for all pressures RUSKA Instrument has two types of hydraulic piston fluids available One is a Spinesstic 22 part number 55 500 which has a density of 0 031 pounds per cubic inch 858 kilograms per cubic meter The other is a Dioctyl Sebacate DOS part number 55 521 1 which has a density of 0 033 pounds per cubic inch 913 kilograms per cubic meter For gas medium piston gauges the values in Column 2 will be different for different system pressures Equations are provided to calculate the density of air or nitrogen as a function of the system pressure F Column 3 is required to adjust the mass density of the pressure medium for local RUSKA 2485 Users Manual A 4 gravity It is also used to correct the pres
66. ection describes the steps necessary to remove and reinstall the instrument cover 1 Remove the test port manifold and nut per Chapter 4 Test Port Manifold Connections 2 Close the appropriate valve to isolate the reservoir from the system 3 Remove the handles from valves A and B the reservoir source valve and if applicable RUSKA 2485 950 valves C and D 4 Remove the screws securing the instrument covers and carefully lift the cover sections from the instrument platform Note The RUSKA 2485 can be safely operated without the instrument covers 5 3 RUSKA 2485 Users Manual Reinstallation of the instrument cover is performed in the reverse order described above Before reinstalling the cover wipe any excess oil from the instrument platform plumbing and valves Do not tighten the instrument cover mounting screws until all the screws have been installed Seal and O ring Replacement After some period of use the seals and o rings in the instrument platform may deteriorate and begin to leak Refer to Chapter 5 Troubleshooting Common Problems for troubleshooting leaks Refer to Chapter 4 Test Port Manifold Connections and Piston Cylinder Assemblies for replacing worn seals and o rings on the piston cylinder assemblies and test port manifold assembly Replacement of the seals in the valves hand pump and intensifier RUSKA 2485 950 only is beyond the scope of this manual Piston Cylinder Cleaning Optimum performanc
67. ed to change ranges in the RUSKA 2485 deadweight gauge is approximately 2 minutes Refer to Figure 4 5 and Chapter 1 Table 1 1 for a detailed view and descriptions of the various piston cylinder configurations Complete cleaning instructions for the various configurations are included in Chapter 5 Maintenance and Troubleshooting 4 6 RUSKA 2485 System Operation A Piston Cylinder Assemblies Selecting a Range There are several factors to consider in the selection of the appropriate denomination piston cylinder assembly for a particular application In the order of general significance they are pressure range nominal and minimum pressure increment pressure resolution using a trim mass set load resolution accuracy at minimum pressure and overall performance characteristics such as free rotation time and float time or sink rate Most deadweight gauges experience a loss in performance at the extreme low end of the pressure range This is usually apparent in the reduced amount of time that the load will remain spinning This loss in performance is typically accounted for through a nominal increase as a percentage of reading in the uncertainty assigned to pressures generated below about 5 or 10 percent of the maximum pressure range depending on the quality of the deadweight gauge Typically the smaller the load on the piston the shorter the rotation time and the more precise any trim adjustment must be An example of this load resolutio
68. ee Chapter 4 Rotate the Masses 1 to 2 turns before continuing 3 Apply any required additional load up to an increase of 20 kilograms 4 large platters and verify level per instructions in Chapter 4 Level the Instrument Platform 4 Increase the pressure until the piston is floating and repeat the procedure in Chapter 4 Load the Masses until the desired load and pressure are obtained 4 10 RUSKA 2485 System Operation 4 Operating Procedure for the RUSKA 2485 Deadweight Gauge Rotate the Masses To generate precise pressures with the RUSKA 2485 deadweight gauge the masses must be rotating For manual rotation of the masses the drive motor is disabled by removing the roller pin slowly begin rotation of the mass stack carefully increasing to approximately 20 revolutions per minute 3 seconds per revolution Hand rotation should be accomplished by grasping the sleeve weight near its top surface and rotating For motorized rotation simply engage the motor by depressing the drive motor power switch For motorized operation the roller pin must be installed in the drive sleeve assembly Refer to Figures 3 1 through 3 3 for locating the roller pin and drive motor power switch Fine Load Adjustment When the RUSKA 2485 is used to generate a specific pressure a small adjustment of the load may be required This adjustment to compensate for conditions such as local gravity air buoyancy and temperature is typically performed through the us
69. efore beginning Complete Chapter 4 Removing a Piston Cylinder Assembly or Shipping Plug before proceeding If a shipping plug is installed rather than a piston cylinder assembly remove it by simply grasping the top edge of the plug and rocking it gently side to side Once the plug 1s free of the housing place it in the appropriate storage location To remove a piston cylinder assembly from the pressure housing use an appropriate insulation between piston cylinder components and fingers and grasp the top edge of the cylinder with the left hand Place the forefinger of the left hand directly above the piston Slowly rotate the hand pump spindle clockwise until the piston extends approximately 1 2 inch 1 cm above the cylinder Place the forefinger of the left hand on the top edge of the piston and apply a slight downward and lateral force to the piston This will prevent the piston from exiting the top of the cylinder while turning the hand pump It will also prevent the piston from exiting the bottom of the cylinder once the assembly is removed from the pressure housing Rotate the hand pump clockwise approximately 3 or 4 turns to free the cylinder from the pressure housing Carefully lift the piston cylinder assembly out of the pressure housing and place it in the appropriate storage container Cover the piston cylinder assembly in the storage container with clean oil and secure the storage container top Wipe any excess oil from the stor
70. el traffic and air drafts Airborne dust is also undesirable but clean room standards are not required The workbench on which the instrument is to be installed must be sturdy enough to safely support up to 400 pounds 180 Kg without significant deformation Ample working space should be allowed where tools worksheets or other technical data can easily be manipulated If the instrument includes the drive motor option or electronic float position temperature option a suitable power source is required at the installation location The power source must be either 115 VAC or 230 VAC and 50 or 60 Hz and must be rated to at least 15 watts Setting Up the Instrument Platform Remove the instrument platform from its shipping box and place it on the workbench Make sure that the circular foot plates are located flat against the workbench surface and that no foreign material is trapped between the foot plates and the workbench Remove any packing materials from the instrument platform and main pressure housing and from inside the internal reservoir Inspect the instrument platform for shipping damage Move the instrument platform to the proper position on the workbench keeping in mind that the final position may be influenced by any pressure connecting lines required to accommodate other equipment Level the instrument platform according to the bulls eye level vial by rotating the two adjustable support legs located at the front and rear of the ri
71. enerate pressure 6 Once the pressure monitor indicates the same pressure noted earlier in this section slowly open system valve D Returning to Atmosphere 1 Carefully rotate the hand pump spindle counter clockwise until the piston is at the lower travel limit and the pressure monitor indicates between zero and 500 psi 35 bar 2 Slowly open reservoir valve A Continue to rotate the hand pump spindle counter clockwise until the pump position indicator approaches the counter clockwise travel limit 4 VERY SLOWLY open intensifier valve C Remember to recharge intensifier before proceeding 4 21 RUSKA 2485 Users Manual Optional Hardware This section describes the electronic float position and electronic temperature sensor options Electronic Float Position The electronic float position option is used to provide high resolution indication of the float position and sink rate of the piston The electronic float position option can increase the reliability and precision of pressure measurements made using the deadweight gauge The electronic float position sensor assembly is installed on the instrument platform below the masses The adjustment and calibration procedures for the electronic float position sensor are included in the operating manual for the display device Electronic Temperature Sensor The electronic temperature option uses a platinum resistance thermometer PRT in conjunction with an electronic display
72. equired to generate such a pressure can be computed from the following equation that combines the corrections described in the previous sections Step by step instructions and worksheets are also included in Appendix A M Pau H R Aelt K where M Total mass required on piston apparent mass for gauge mode true mass for absolute mode to generate the desired pressure includes tare mass and surface tension aM Pressure at reference plane of device under test H Head pressure Chapter 2 Hydraulic Fluid Pressure Gradients R Reference pressure absolute mode typically 100 mTorr da Effective area corrected to working temperature see Chapter 2 effective Area of the Piston Cylinder Assembly and k Mass force conversion factor see Chapter 2 Force 2 9 RUSKA 2485 Users Manual Mass to Pressure Equation Some measurement condition may require that a load be applied to the deadweight gauge to measure an unknown pressure The exact pressure generated for a given load can be computed from the following equation that combines the corrections described in the previous sections Step by step instructions and worksheets are also included in Appendix A _MK P 4 R H ut where Le Pressure at reference plane of device under test M Total mass loaded on the piston apparent mass for gauge mode true mass for absolute mode to generate the pressure includes tare mass and surface tension k Mass forc
73. er depressurization of the system the hand pump may be discharged while the system remains at pressure To discharge the hand pump while the system is at pressure l Verify that pressure valve B is open and adjust the hand pump position so that approximately one quarter of the pump travel remains in the counter clockwise direction Note the system pressure indicated on the pressure monitor Close pressure valve B and carefully rotate the hand pump spindle counter clockwise until the pressure monitor indicates between zero and 500 psi 35 bar Open reservoir vale A and rotate the hand pump spindle clockwise until approximately one quarter of the pump travel remains in the clockwise direction Close reservoir valve A and carefully rotate the hand pump spindle clockwise to generate pressure Once the pressure monitor indicates the same pressure noted earlier slowly open pressure valve B Returning to Atmosphere RUSKA 2485 System Operation Valve Operating Procedure RUSKA 2485 950 Verify that pressure valve B is open 2 Rotate the hand pump spindle counter clockwise until the piston is at the lower travel limit and the pressure monitor indicates between zero and 500 psi 35 bar 3 Slowly open reservoir valve A Valve Operating Procedure RUSKA 2485 950 See Plumbing Schematic Figure 4 2 This section describes the proper valve operating procedures for the various functions of the RUSKA 2485 950 deadweight gauge instr
74. eservoir and hand tighten the test port manifold retaining nut The test port manifold is now sealed and the device under test can be bled of air if necessary by pumping oil through the test port manifold and device under test 4 5 RUSKA 2485 Users Manual Mass Loading Table Removal and Installation N Caution All pressure must be removed from the system prior to disconnecting the mass loading table assembly from the main pressure housing Remove all pressure from the system and close the appropriate valve to isolate the reservoir Refer to Chapter 4 Valve Operating Procedure for RUSKA 2485 930 and Valve Operating Procedure for RUSKA 2485 950 for the specific valve operating sequence Refer to Figures 4 4 and 4 5 Loosen the mass loading table assembly retaining nut until it is free of the threads on the main pressure housing Carefully lift the mass loading table assembly off of the main pressure housing At this point the piston cylinder assembly or a shipping plug will be exposed and appropriate care should be taken to prevent damage or contamination The exposed piston cylinder assembly can be covered with a clean paper wiper to prevent contamination from airborne dust Clean any oil from the mass loading table components prior to reinstallation To install the mass loading table assembly onto the main pressure housing carefully guide the mass loading table assembly retaining nut and cylinder spacer inside the nut
75. f the main pressure housing a test port manifold is supplied with an assortment of adapters The test port manifold with the appropriate adapter installed is designed to be mounted to the auxiliary pressure housing without the use of tools The design of the test port manifold allows simple and quick installation of the manifold while promoting durability of the seal A Caution Due to the thread configuration of some of the adapters they may not be rated to the full pressure of the instrument Refer to Figure 4 2 for appropriate pressure rating of each adapter Functional Description 019 Test Port Manifold Retaining Nut The test port manifold retaining nut secures the test port manifold to the auxiliary pressure housing to provide a positive seal at full instrument pressure Securing the test port manifold to the auxiliary pressure housing with the retaining nut requires no tools RUSKA 2485 Users Manual Functional Description Oil Drain Line During operation of the instrument oil passes between the precision surfaces of the piston and cylinder assembly This oil drains down the main pressure housing and lubricates the drive sleeve bearings As the oil flows out of the drive sleeve it drains through a hole in the instrument base Beneath the base the oil is collected in a clear plastic tube This tube is equipped with a barbed connection An additional length of tubing is found in the setup kit Mate the tubing found in
76. g control over the influence or by measuring the effects and applying corrections Some of the factors that influence pressure measurements are below Elastic distortion of the piston cylinder assembly Piston cylinder temperature Gravitational acceleration Atmospheric buoyancy Pressure gradients Float position of height Surface tension Vertical alignment of piston axis Pressure results from the application of a force onto an area Numerically it is the quotient of the force divided by the area onto which it is applied P F A where P pressure F force and A cross sectional area Some of the influences stated above have a direct effect on the area of the piston cylinder assembly while other factors affect the force or the pressure Corrections based on these influences are described accordingly in the following sections Two final equations combining all the corrections are described at the end of the section one equation for computing the mass required to generate a desired pressure and a second for computing the pressure generated for a given load As there are many engineering units established for pressure measurements it is important to ensure that the units affixed to each parameter used in the computations are matched to the engineering pressure unit desired Further explanation and worksheets are included in Appendix A 2 1 RUSKA 2485 Users Manual 2 2 Effective Area of the Piston Cylinder Assembly T
77. ght side of the instrument platform The voltage selector switch position must be verified prior to applying power As shown in Figure 4 3 the selected voltage is displayed through a small window in the power cord receptacle on the rear of the drive motor assembly If the incorrect voltage is displayed the voltage selector switch position and the fuses must be changed To change the voltage selector switch position and fuses open the voltage selector fuse holder compartment on the power receptacle using a flat blade screwdriver in the slot directly above the voltage display window Remove the voltage selector wheel rotate to the proper setting and reinstall N Caution Do not rotate the selector wheel while it is installed Slide out both fuse holder trays and verify that the proper fuses are installed Close the voltage selector fuse holder cover and verify that the proper voltage 1s displayed 4 2 RUSKA 2485 System Operation A Installation and Preparation for Use A power pigtail with a female plug Style IEC 60320 emerges from the lower surface of the drive motor assembly This pigtail supplies power to the fill pump assembly mounted below the base See Figure 3 9 This pigtail may have come loose during shipping Verify that this pigtail is securely inserted into the male socket power inlet on the fill pump sub assembly Read the sections regarding fill pump operation before energizing the fill pump Ensure that the drive belt
78. he applicable international price Fluke reserves the right to invoice Buyer for importation costs of repair replacement parts when product purchased in one country is submitted for repair in another country Fluke s warranty obligation is limited at Fluke s option to refund of the purchase price free of charge repair or replacement of a defective product which is returned to a Fluke authorized service center within the warranty period To obtain warranty service contact your nearest Fluke authorized service center to obtain return authorization information then send the product to that service center with a description of the difficulty postage and insurance prepaid FOB Destination Fluke assumes no risk for damage in transit Following warranty repair the product will be returned to Buyer transportation prepaid FOB Destination If Fluke determines that failure was caused by neglect misuse contamination alteration accident or abnormal condition of operation or handling including overvoltage failures caused by use outside the product s specified rating or normal wear and tear of mechanical components Fluke will provide an estimate of repair costs and obtain authorization before commencing the work Following repair the product will be returned to the Buyer transportation prepaid and the Buyer will be billed for the repair and return transportation charges FOB Shipping Point THIS WARRANTY IS BUYER S SOLE AND EXCLUSIVE REMEDY AN
79. he position where pressure head corrections will be valid Significant deviations from this position can result in head pressure errors but will likely result in greater errors as a result of slight variations in the taper or other geometric aspect of the piston or cylinder of a given assembly Typically the pressure in a system is adjusted to obtain a float position slightly above mid float and the normal leakage of the pressure medium through the clearance between the piston and cylinder will allow the piston to slowly descend through the mid float position Assuming adequate time has been allowed for thermal stabilization and no significant leaks are present n the system this is the time when a measurement should be made Minimum Pressure For most piston pressure gauges there is a minimum pressure that can be generated by floating the piston This tare pressure is that which is required to float the minimum load on the deadweight gauge which may be the piston alone Although there is usually a substantial degradation in uncertainty percent of reading at tare pressure it is often required as a calibration point It is also however one of the most frequently overlooked considerations in the operation of a deadweight gauge and one that if ignored in tabulating the total piston load will result in a substantial error Pressure to Mass Equation Some measurement condition may require that a specific pressure be generated The exact load r
80. hile firmly holding the cylinder in place press the piston down into the cylinder then press the cylinder down firmly against the o ring cylinder seal To install a shipping plug rather than a piston cylinder assembly carefully insert the bottom of the shipping container into the pressure housing Open the appropriate valve to activate the reservoir Press the shipping container down firmly against the o ring cylinder seal Installing the Mass Loading Table Assembly RUSKA 2485 930 and RUSKA 2485 950 As described in Chapter 4 Mass Loading Table Removal and Installation carefully guide the mass loading table assembly retaining nut and cylinder spacer inside the nut over the piston cylinder assembly and tighten the retaining nut As the o ring and or seal compress some amount of feedback in the form of resistance will be felt by the operator Continue to tighten the nut until the o ring seal compression is complete as indicated by a sudden increase in resistance when the cylinder spacer inside the nut contacts the top of the main pressure housing Secure the nut using the spanner wrench part number 94 618 provided in setup kit part number 2485 202 or 2485 203 Operating Procedure for the RUSKA 2485 Deadweight Gauge This section describes the steps necessary to safely generate precise pressures with the RUSKA 2485 deadweight gauge The steps described below are generic and are applicable to both versions of the instrument Specifi
81. ilogram loaded on the piston the nominal pressure increment will be 200 psi For a piston cylinder assembly with a BO 5 pressure unit increment designator S I units each kilogram would generate 0 5 bar A B50 piston cylinder will generate 50 bar per kilogram or 5000 bar 72 500 psi for the full mass load of 100 kilograms The RUSKA 2485 cylinders are simple in configuration and there are no mounting flanges or other geometric irregularities that can result in complicated stresses in the cylinder Further the cylinder is restrained in the pressure housing in such a way as to minimize stress due to mounting and sealing The mounting arrangement for the piston cylinder assemblies in the pressure housing also allows quick and easy change out of all ranges while providing a maximum level of protection to the precision measuring components High Pressure Piston Cylinder Assemblies Due to the extreme stress at pressures up to 72 500 psi 5000 bar the high pressure piston cylinder assemblies have a slightly different geometry than the lower pressure assemblies The high pressure piston cylinder assemblies retain the non complex configuration with the seal at the bottom of the cylinder The piston and cylinder are however significantly smaller To assure proper alignment of the high pressure assemblies and to ensure positive sealing at the base of the cylinder a special cylinder keeper is installed in the pressure housing prior to installation
82. increase in the effective area of the simple cylinder is also accompanied by an increase in the leakage of the fluid past the piston Indeed the leakage becomes so great that at some pressure the floating time will not be sufficient for an accurate pressure measurement In Figure 2 2 the pressure fluid is allowed to surround the body of the cylinder The pressure drop occurs across the cylinder wall near the top of the cylinder at B but in the opposite direction to that of the simple cylinder in Figure 2 1 In consequence the elastic distortion is directed toward the piston tending to decrease the effective area of the assembly Again the change in the area with pressure places a limit on the usefulness of the re entrant cylinder as a primary instrument Some benefit does result however from the use of the re entrant cylinder because higher pressures may be attained without a loss in float time A small sacrifice is made in the float time at lower pressures because the total clearance between piston and cylinder is generally greater with a simple cylinder design In the controlled clearance design of Figure 2 3 the cylinder is surrounded by a chamber to which a secondary pressure system is connected Adjustment of the secondary or chamber pressure permits the operator to change the clearance between the cylinder and piston at will A series of observations involving piston sink rates at various jacket pressures leads to the empirical determin
83. ined in procedures that will assure safety to themselves to others and to the equipment N Warning If the equipment is used in a manner not specified by the manufacturer the protection provided by the equipment may be impaired 1 1 RUSKA 2485 Users Manual N Warning Do not exceed safe maximum generated pressures as follows 2485 930 20 000 PSI 1 400 bar 2485 950 Hand Pump System 20 000 PSI 1 400 bar 2485 950 Main Housing amp Test Port Manifold 72 500 PSI 5 000 bar Always use replacement parts specified by Fluke When any maintenance is performed turn off power and remove power cord Caution Do not mix fluid types Fluid types available Spinesstic 22 oil dioctyl sebacate DOS Do not exceed the safe working pressures for the test port manifold adapters Refer to markings on the adapters and to Figure 4 2 for safe operating pressure Symbols Used in this Manual In this manual a Warning identifies conditions and actions that pose a hazard to the user A Caution identifies conditions and actions that may damage the Hydraulic Piston Gauge or the equipment under test Symbols used on the Pressure Calibration System and in this manual are explained in Table 1 1 Table 1 1 Symbols AC Alternating Current Important Information refer to manual Do not dispose of this product as unsorted municipal waste Go to Fluke s website for recycling information General Specifications 1 2
84. inside the mass loading table assembly Refer to Chapter 3 3 1 RUSKA 2485 Users Manual Functional Description Pressure Valve B Pressure valve B serves two functions In the low pressure version RUSKA 2485 930 pressure valve B allows recharging of the hand pump while the system remains at pressure by isolating the pump and reservoir from the system In the high pressure version RUSKA 2485 950 which includes an integral pressure intensifier pressure valve B is used as the reservoir cutoff valve for pressures up to 20 000 psi 1400 bar and is opened when activating the intensifier to generate pressures up to 72 500 psi 5000 bar Intensifier Valve C The high pressure version RUSKA 2485 950 includes an integral intensifier After charging the system to approximately 20 000 psi 1400 bar intensifier valve C is closed to activate the intensifier for pressure generation up to 72 500 psi 5000 bar Intensifier Valve D System valve D on the high pressure version RUSKA 2485 950 serves two functions The primary function of system valve D is to allow recharging of the integral intensifier without removing the pressure from the system A secondary function of system valve D is fine adjustment of the float position of the high pressure pistons when the friction of the seals in the intensifier do not allow such fine control 007 Pump Position Indicator The RUSKA 2485 incorporates a hand operated positive displacement screw typ
85. into one term K used as a conversion between mass and force For gauge mode operation the conversion is between force and apparent mass For absolute mode operation where nearly all the air is removed from around the masses such that the buoyant effect is typically insignificant the conversion is between force and true mass K 1 D D G G where K Mass force conversion factor D Air density D Mass reference density G Local gravitational acceleration in m s and G Standard gravitational acceleration 9 80665 m s Surface Tension For many hydraulic deadweight gauges the surface tension of the pressure medium acting on the piston exerts a downward force that is significant to some pressure measurements The effects of surface tension are commonly included in the total mass value provided for the tare components but may be applied as a separate correction Pressure Corrections and Other Miscellaneous Factors Hydraulic Fluid Pressure Gradients When gravity acts on a column of fluid such as in a liquid manometer a pressure is generated at the bottom of the column nominally equal to the height of the column multiplied by the density of the fluid The same pressure gradient exists in a hydraulic deadweight gauge calibration system For two different positions within the calibration system a difference in pressure exists that is nominally equal to the density of the fluid multiplied by the vertical separation between
86. mass load Level Vial A sensitive bulls eye level vial is mounted at the front of the instrument platform to provide easy measurement of the level of the instrument When the axis of rotation of the piston cylinder assembly is significantly off of vertical the bubble in the level vial will be conspicuously out of center Drive Motor Assembly The principal use of the drive motor is to maintain consistent relative motion between the piston and cylinder when the inertia of a small mass load is insufficient to maintain adequate free rotation time The drive motor assembly also supplies power to the fill pump assembly RUSKA 2485 930 amp RUSKA 2485 935 Only Power Receptacle And Fuse Holder Power to the optional drive motor assembly is switchable between 115 or 230 VAC and 50 or 60 Hz The power RECEPTACLE on the rear of the drive motor assembly contains the necessary fuses to prevent electrical overload of the motor Technical Description 3 Instrument Features and Functions Functional Description Drive Motor Fill Pump Power Switch The drive motor assembly is equipped with a power switch on the left end This power switch controls the drive rotation motor and on the RUSKA 2485 930 and RUSKA 2485 935 the switch also controls the motorized fill pump Drive Motor Power Lamp The drive motor assembly includes an indicator lamp to show the state of the electrical motor The lamp is located on the left side of the drive
87. masses RUSKA 2485 Users Manual Deadweight Gauge Piston As with the mass set preservation of the high precision operating surfaces of the piston cylinder assembly will prolong the reliability and long term stability of the deadweight gauge piston Always handle the piston cylinder assembly in accordance with the instructions provided in the operating manual Proper handling of these assemblies will typically result in a recalibration schedule of about 3 or 4 years Calibration of a deadweight gauge piston cylinder assembly is typically performed through direct intercomparison with a standard piston cylinder having known effective area coefficients The calibration report for a piston cylinder assembly will typically include an effective area at zero pressure pressure and temperature coefficients mass density and surface tension values for the tare components uncertainty estimates and other traceability information The piston calibration process is often referred to as the crossfloat In a typical crossfloat both the standard and test deadweight gauges are connected together and operated simultaneously The difference in the pressures generated by the two gauges is reduced to a level beyond the performance of the measurements process The degree to which the pressures are matched and the random uncertainty of the measurement process contributes to the total uncertainty is limited by the performance of the system which is only as good a
88. motor assembly next to the power switch Drive Belt The rotary action of the drive motor is transferred to the drive sleeve through an elastomeric drive belt installed on the pulleys mounted on the drive motor and the drive sleeve Drive Sleeve A thin line machined around the periphery of the drive sleeve approximately 3 16 of an inch 5 mm above the drive belt pulley is used as a reference for measuring the proper float position of the piston cylinder assembly Pressure is applied to the piston cylinder assembly until the piston and mass load are floating at a position where the bottom edge of the hanger mass designation 01 coincides with the line on the drive sleeve The drive sleeve provides the rotary motion for the mass loading table through contact with a roller pin mounted in the top of the drive sleeve The drive sleeve also provides a boundary between the mass load and the oil draining down the side of the main pressure housing Roller Pin The roller pin mounted in the top of the drive sleeve provides rotation of the mass loading table assembly through contact with a drive pin in the bottom of the mass loading table The roller pin can be removed by simply grasping the pin and lifting It is recommended that the roller pin be removed when not required and that motor driven rotation be used only when a small load or other special test requires its use Float Position Mirror Block A small mirror mounted to the float positio
89. ms or larger are installed on the mass loading table If the proper response is not obtained the sensor or the control box may be damaged Electronic Temperature Sensor If the temperature of the deadweight gauge is not being measured correctly by the electronic temperature indicator verify that electrical connection to the sensor is secure If the proper response is not obtained the sensor or the control box may be damaged TUBE FITTING HOLD DOWN RING RUPTURE DISK TORQUE NUT MAIN BODY gmd25 eps Figure 5 1 Safety Head and Rupture Disk Maintenance and Troubleshooting Options 1 LOW RANGE CYLINDER CLEANING TOOL WITH CLEANING TOOL KIMWIPE INSERTED SEE ee 4 3 INSERT CLEANING TOOL KIMWIPE WRAPPED AROUND INTO CYLINDER CLEANING TOOL gmd26 eps Figure 5 2 Low Range Cylinder Cleaning TWIST DIAGONALS OF KIMWIPE 1 CLEAN KIMWIPE oo INSERT KIMWIPE INTO 3 MID OR HIGH RANGE CYLINDER ROLL KIMWIPE gmd27 eps Figure 5 3 Mid High Range Cylinder Cleaning 5 9 RUSKA 2485 Users Manual 5 10 Appendix A Calculations Explanation of Pressure Calculation Worksheet Tables A9 and All These tables may be used with gas and hydraulic piston pressure gauges that are operated with an atmospheric reference or vacuum reference P represents the pressure at the piston reference gauge level P represents the pressure desired at the device under test and P is the hea
90. n 9 is the apparent mass that is required to produce the force listed in Column 8 Column 10 is a listing of the different masses to be loaded on the piston pressure gauge to create the pressure listed in Column 5 The masses which will be listed here are in addition to the tare components piston surface tension effects bell jar reference pressure etc The mass of the tare components must be subtracted from the mass shown in Column 9 before selection of the miscellaneous masses is started After subtracting the TARE mass from the Total Mass shown in Column 9 we must now subdivide distribute the remaining required mass value among the available masses that will be loaded onto the Piston Table Assembly It is most likely that there may be many combinations of available masses that could be used to yield the required Total Mass However it is strongly recommended that an orderly and sequential method by used From the Mass Set Table calibration report first determine if the Sleeve Mass is required which would be the case if the realization of the Total Mass value would require the use of the larger platter masses If yes then subtract its mass value from the Total Mass value which results in a new remainder From this remainder mass value choose the next largest available mass value that may be subtracted If the choice is from one of several nominal mass platters then choose the first one in the available sequence Subtract this v
91. n Cylinder Specifications Mass SCE Specifications nee 2 PISTON Pressure Gauge uuu IIIa Issa asssussaiawaqass agan auqaunawausukiawqusanqa Measurement Consideral 018 nennen Effective Area of the Piston Cylinder Assembly Types of Piston Pressure Gauges Elastic Distortion of the Piston Cylinder Assembly Buoyant Effect OF the Al aussehen Combined Gravity and Air Buoyancy Correction LACS Ten SION nee Pressure Corrections and Other Miscellaneous Factors Hydraulic Fluid Pressure Gradients uesseeeeeeeeeeeeeeeeeeeeeneeennnnnnnnneeennnn Pheummatie Pressure Gra iC Ms xs neusten sure Reference Pressure Head o Post Otay gars tse sett en re Minimum PresSUIG Pressure to Mass Equalion nannten Mass to Pressure Equation ci sun Conditions Favorable For a Measurement Accuracy and Traceability ua aasayawaaaaaashanaaaqaasskaaaqasaaqaqqaaqawayakasqusqasqhaq Deadweight Gauge Masses aaasssssssssssssssssssssssa Deadweight Gauge Piston
92. n factor follows The pressure generated by a piston operating at the full load of 100 kilograms would change one part per million ppm for a change in the load of 100 milligrams mg The change in the pressure generated by a higher range piston with a total load of only 5 kilograms however would change 20 ppm for the same 100 mg trim adjustment A general guideline for selecting the appropriate piston cylinder is to select the lowest range that covers the pressures in the particular application If two ranges are required for a particular evaluation use the lower range up to its maximum rating and overlap one or two pressures using the higher range Piston Cylinder Identification All RUSKA 2485 piston cylinder assemblies are permanently marked with the pressure unit increment designator the assembly serial number and the word top to ensure proper orientation when installed into the main pressure housing The top of each piston is rounded to ensure alignment and proper operation of the mass loading table assembly It is crucial that the piston and cylinder be installed in the proper orientation Refer to Figure 3 11 and Figure 4 5 for a detailed view of the piston cylinder markings and orientation When a RUSKA 2485 piston cylinder assembly is not installed in the instrument it should be stored in the shipping storage container supplied with each assembly The label on the container identifies the denomination and serial number of the pi
93. n increase the pressure When descending to a lower pressure first reduce the pressure then reduce the load N Caution When removing masses from the deadweight gauge while the system is pressurized the piston may rise to the top of travel This movement must be anticipated and controlled to prevent damage to the equipment Return to Atmosphere When all pressure measurements have been made return the instrument to atmospheric pressure Unload the masses from the deadweight gauge and store them in the appropriate location LOW HIGH PRESSURE PRESSURE RESERVOIR VALVE BY PASS VALVE TOP RN RELEIF VALVE _ 100 PSI PISTON TEST PORT RESERVOIR FILL PUMP disk PRESSURE 22 KPSI FOR 2485 930 INDICAT 46 KPSI FOR 2485 935 DIAL GAGE gmd17 eps Figure 4 1 Lo and Mid Press Plumping Schematic 4 12 RUSKA 2485 System Operation Valve Operating Procedure RUSKA 2485 930 Preparation for Storage Shipping RUSKA 2485 930 and RUSKA 2485 950 When the RUSKA 2485 deadweight gauge is not in use the pressure should be removed and the appropriate valves open to the reservoir The following section describes the recommended steps to prepare the instrument platform for shipment or long term storage l Remove all the masses loaded on the deadweight gauge including the hanger mass Install the shipping plug according to Chapter 4 Piston Cylinder Identific
94. n mirror block at a 45 degree angle provides easy visual observation of the float position of the hanger mass relative to the line on the drive sleeve Float Position Sensor Assembly An optional electronic float position sensor assembly is available under part number 2485 913 The electronic sensor allows more precise and simpler measurement of the float position through the use of the RUSKA 2456 piston gauge monitor or other device Optional Thermometer Assembly A liquid in glass thermometer with protective metal sleeve and mounting hardware is available as an Option P N 2485 202 913 Temperature measurement is required to minimize the thermal effects when operating the RUSKA 2485 Piston Pressure Gauge An electronic thermometer PRT is also available as an option RUSKA 2485 Users Manual Functional Description 3 6 036 Mass Set Each individual piece in the mass set is completely machined from non magnetic 300 series stainless steel in kilogram denominations to provide easy direct comparison to mass standards in the meter kilogram second system of measure The final mass is adjusted to within 15 parts per million of the nominal denomination in units of apparent mass versus brass standards density reference 8 4 g cm The adjustment is performed in such a way as to maintain a balance about the centerline by milling a symmetrical pattern of holes on the bottom surface of the mass concentric with the axis The mass set
95. n pressure housing or level vial has been removed or damaged readjustment of the level vial may be necessary The level vial should be adjusted such that when the bubble in the level vial is centered the top surface of the main pressure housing is level within 5 minutes of arc Instrument Platform Lubrication Several components of the instrument platform may require periodic lubrication to provide reliable enduring service A drop or two of light machine oil in the threads and swivel sockets of the support legs may be required when the instrument is placed in service and every few years thereafter The hand pump spindle and spindle nut bearings require lubrication to operate properly Both are lubricated at the factory but require inspection when the instrument is placed in service and every few years thereafter Remove the pump lubrication port cover Figure 3 4 add 2 3 drops of clean 90W to 140W oil and replace the pump lubrication port cover During operation of the deadweight gauge the oil passing through the minute clearance between the piston and cylinder and the overflow oil during piston cylinder exchange will provide lubrication for the drive sleeve bushings When the instrument is placed in service and during each piston cylinder exchange when the mass loading table assembly has been removed verify that the drive sleeve bushing has an ample amount of lubrication Packing Adjustment for Valves l Remove all pressure from
96. ockwise to generate pressure 5 Once the pressure monitor indicates the same pressure noted earlier slowly open intensifier valve C Discharging the Hand Pump While at Pressure When reducing pressure in the system the pump may reach the counter clockwise travel limit before the desired pressure is obtained To allow further depressurization of the system the hand pump may be discharged while the system remains at pressure To discharge the hand pump while the system is at pressure l First verify that reservoir valve A intensifier valve C and system valve D are open then adjust the hand pump position so that approximately one quarter of the pump travel remains in the counter clockwise direction RUSKA 2485 Users Manual 4 18 Close intensifier valve C and note the system pressure indicated on the pressure monitor for use later in this section Carefully rotate the hand pump spindle counter clockwise until the pressure monitor indicates between zero and 500 psi 35 bar Open pressure valve B and rotate the hand pump spindle clockwise until approximately one quarter of the pump travel remains in the clockwise direction Close pressure valve B and carefully rotate the hand pump spindle clockwise to generate pressure Once the pressure monitor indicates the same pressure noted earlier in this section slowly open intensifier valve C Returning to Atmosphere Rotate the hand pump spindle counter clockwise until the piston is
97. pressure decreases accordingly If the containment is a deadweight piston gauge the piston will rapidly descend into the cylinder resulting in an unusually high sink rate until such a time as the fluid and containment reach thermal equilibrium This thermal or adiabatic effect is bi directional When the fluid is depressurized it undergoes a sudden decrease in temperature As the fluid absorbs heat from the containment the resulting sink rate will be abnormally low until the system again reaches equilibrium In fact this effect may result in a rise in float position Depending on factors such as volume rate of pressurization internal surface area of the system and fluid characteristics the time required for equilibration may exceed 30 minutes Typically however only 5 to 10 minutes are required for adequate operation of the deadweight gauge Piston Pressure Gauge 2 Accuracy and Traceability Other factors also induce temporary effects on the pressure and sink rate A pocket of gas trapped in a hydraulic system will tend to dissolve into the oil upon pressurization This action may not be instantaneous and as the gas pocket dissolves the pressure will tend to decrease Occasionally the seals and packing In valves may yield under the stress of pressurization This deflection also may not be instantaneous and can result n an abnormal sink rate Only after the effects of these influences have subsided and provided that no significant le
98. ront of the instrument N Caution Do not rotate the hand pump spindle during installation of the handles 4 3 RUSKA 2485 Users Manual 4 4 9 Carefully tighten the hand pump handles using a wrench on the flats near the pump spindle end of each handle Slowly rotate the hand pump spindle counter clockwise until the pressure displayed on the pressure mounted on the top of the instrument indicates between zero and about 500 psi 35 bar A Caution Be very careful not to go below zero as air will be pulled into the hydraulic system Carefully open Reservoir Valve A on the right side of the instrument Slowly rotate the hand pump spindle in the clockwise direction while monitoring the oil level in the internal reservoir As the oil level rises above the fitting in the bottom of the reservoir continue to rotate the hand pump in the clockwise direction while looking for gas bubbles in the oil Continue rotating the hand pump until no gas bubbles emerge from the reservoir plumbing Add oil to the reservoir from a fresh clean source until the oil level is near the fitting in the side of the reservoir N Caution Be certain that the oil added to the reservoir is the same type as that in the instrument Recharge the hand pump by rotating the pump spindle fully counter clockwise then clockwise one quarter turn to remove any backlash in the spindle threads Close Reservoir Valve A 10 Slowly rotate the hand pump spin
99. s the worst component or aspect of the system To obtain a level of performance in the crossfloat system that is better than a few parts In one hundred thousand not only must both piston cylinder assemblies be of sufficiently high quality but some means of amplification of pressure or float position will also be necessary Several methods of crossfloating using such electronic aids exist that enable adjustment of the loads and matching of the pressure to less than one part per million Bibliography l Bridgman P W The physics of High Pressure G Bell amp Sons London 1952 2 Cross J L Reduction of Data for Piston Gauge Pressure Measurements NBS Monograph 65 1963 3 Dadson R S The Accurate Measurement of High Pressures and the Precise Calibration of Pressure Balances Proc Conf Thermodynamic and Transport Properties of Fluids London pp 32 42 1957 Institute of Mechanical Engineers 4 Design and test of Standards of Mass NBS Circular No 3 Dec 1918 Included in NBS Handbook 77 Volume III 5 Johnson D P J L Cross J D Hill and H A Bowman Elastic Distortion Error in the Dead Weight Piston Gauge Ind Engineering Chem 40 2046 Dec 1957 6 Johnson D P and D H Newhall The Piston Gauge is a Precise Measuring Instrument Trans of ASME April 1953 7 Newhall D H and L H Abbot Controlled Clearance Piston Gauge Measurements and Data Jan Feb 1970 8 Pressure Me
100. s well as the reference temperature are listed in the calibration report for the piston cylinder assembly Some typical thermal coefficients and materials are shown in the following table refer to the calibration report for actual values Table 2 1 Typical Thermal Coefficients Piston Cylinder Thermal Coefficient Material Material per degrees Celsius WC Tungsten Carbide 2 4 Piston Pressure Gauge 2y Measurement Considerations Force Gravitational Acceleration Pressure is a function of force per unit area Any action that affects the force applied to the piston proportionally affects the pressure generated with the piston Masses applied to a piston are accelerated in a downward direction by the gravitational attraction of the earth thereby exerting a force on the piston Gravitational acceleration varies from location to location thus so do the forces exerted on the piston by a given mass The gravitational acceleration at different locations within the continental United States and the resulting variations n pressure for a piston pressure gauge vary by more than 0 17 per cent Corrections for these gravitational variances are performed according to the following equality F M G G where F Downward force M Mass of object G Local Gravitational Acceleration in m s and G Standard Gravitational Acceleration 9 80665 m s M Cosine Error It is important to note that the gravitational effect is in
101. se the pressure in the test port As the intensifier builds pressure in the high pressure system the pressure monitor will also indicate an increase In the low pressure system but not at the same rate as before the intensifier plunger began to move This is due to the intensifier plunger movement changing the volume of the low pressure system RUSKA 2485 System Operation Valve Operating Procedure RUSKA 2485 950 The relative rate of pressure change in the hand pump as indicated by the pressure monitor is an important indication in the operation of the system If the pressure rate does not change at the appropriate pressure according to the intensifier ratio the intensifier has reached the high pressure travel limit and must be recharged before continuing Refer to Chapter 4 for instructions on recharging the intensifier Note The basic intensifier ratio is 4 7 1 The actual pressure ratio will be slightly different due the friction of the seals in the intensifier Adjusting Float Position As the pressure approaches that required to float the piston reduce the rate of hand pump spindle rotation and slowly approach the proper float position If the float position or system pressure is too high 1 Rotate the hand pump spindle counter clockwise until the proper pressure or float position is obtained 2 Rotate the hand pump spindle one additional turn counter clockwise and then carefully clockwise to operate the intensifier and adjust
102. sition Note The reservoir supply plumbing incorporates a relief valve to prevent accidental over pressurization of the supply plumbing The relief vale is set at the factory to 150 psi 10 bar Maintenance and Troubleshooting Troubleshooting Common Problems For RUSKA 2485 950 repeat the above test for pressure valve B To test pressure vale B for RUSKA 2485 930 close reservoir valve A and pressurize the system to 100 psi Close pressure valve B and open reservoir valve A If the pressure monitor attached to the test port manifold indicates leakage through pressure valve B it must be repaired Drive Motor If the mass stack does not rotate when power is applied to the drive motor use the following procedure to diagnose the failure e Ifthe motor does not rotate when the proper power is applied disconnect the power check the power setting and if necessary replace the fuse refer to Chapter 4 Setting Up the Instrument Platform If this fails the motor may be damaged e Ifthe drive motor operates properly but the drive sleeve does not rotate verify that the drive belt is clean not damaged and is properly adjusted Verify that the drive sleeve bushings are not damaged and are properly lubricated e Ifthe drive motor operates properly and the drive sleeve rotates but the mass loading table does not verify that the roller pin is properly installed in the top of the drive sleeve refer to Figures 3 1 through 3 3 Verify that the
103. solate segments the system Most leaks in fittings will result in droplets of oil forming at the fitting tubing or bleed port for the connection Leaks n valves and seals may be more difficult to isolate Leaks in core packing of reservoir vale A and pressure valve B are usually more apparent at pressures below 500 psi 35 bar To test these valves install a shipping plug in the main pressure housing according to Chapter 4 and connect a pressure monitor with 50 psi 5 bar or better resolution to the test port manifold l Recharge the hand pump according to Chapter 4 Valve Operating Procedure for RUSKA 2485 930 or Valve Operating Procedure for RUSKA 2485 950 as applicable 2 Verify that pressure valve B is open and if applicable RUSKA 2485 950 valves C and D are open 3 Close reservoir valve A and slowly rotate the hand pump clockwise to generate approximately 100 psi If the pressure can not be generated there may be air trapped in the system or there may be a leak 4 Ifreservoir valve A appears to be leaking open reservoir vale A and recharge the hand pump 5 Verify that valve A is open and rotate the reservoir source valve ONE QUARTER turn to a position half way between internal and external Carefully pressurize to 100 psi see note below 7 Ifthe system response is now normal reservoir vale A leaks and must be repaired Otherwise remove the pressure and rotate the reservoir source valve to the appropriate po
104. ston cylinder assembly The container can be stored in the mass set storage box that contains the incremental platters and the hanger mass Piston Cylinder Installation and Exchange RUSKA 2485 930 and RUSKA 2485 950 N Caution All pressure must be removed from the system prior to installing or exchanging a piston cylinder assembly in the main pressure housing N Caution Whenever handling the precision piston cylinder components of the RUSKA 2485 deadweight gauge use plastic or thin rubber gloves or several thicknesses of low lint paper wipers such as Kimberly Clark Type 900 Kimwipes part number 58 392 to prevent finger oils and salts from contacting the components 4 7 RUSKA 2485 Users Manual Removing the Mass Loading Table Assembly Remove all pressure from the system and close the appropriate valve to isolate the reservoir Refer to Chapter 4 Valve Operating Procedure for RUSKA 2485 930 RUSKA 2485 935 and Valve Operating Procedure for RUSKA 2485 950 for the specific valve operating sequence Remove the tare compensator disk and mass loading table assembly according to Chapter 4 Mass Loading Table Removal and Installation and place them in an appropriate location Removing a Piston Cylinder Assembly or Shipping Plug RUSKA 2485 930 and RUSKA 2485 950 The procedure for removing a piston cylinder assembly from the main pressure housing includes several critical steps Read the entire procedure carefully b
105. sure head that exist between the reference ports of the piston gauge and device under test Column 4 P is the pressure correction that is required if the reference plane of the device being calibrated is not the same plane as the reference plane of the piston pressure gauge The difference between the two planes h is positive if the reference plane of the device being calibrated is higher than the reference plane of the piston pressure gauge Column 5 is the pressure required at the reference plane of the piston pressure gauge to produce the desired pressure at the reference plane of the device being calibrated When the piston gauge is operating in the absolute mode the Reference pressure Pr is subtracted to obtain the differential pressure that the piston is required to generate The value of 1 bP b P which is used to determine the piston area at different system pressures is recorded in column 6 For some pistons b and or b are equal to zero Always observe the sign in front of b and b as found in the calibration report Column 7 is used to record A which is the area of the piston at pressure P and at the expected temperature t Column 8 the weight load is the force required on a piston of given area to produce a given pressure F P A A eft where F Weight load or force on the piston ig Pressure as indicated in Column 5 Aoi Effective piston area at the expected temperature t I Colum
106. sus ae AS s sb li yuca baina aaa aspina assasi Execute Pressure Measurement l Ti j ae een ee Return to Atmosphere euere en Preparation for Storage Shipping RUSKA 2485 930 and RUSKA 2485 950 unse eek Valve Operating Procedure RUSKA 2485 930 Recharging the Hand Pump at Atmospheric Pressure Pressurizins the System on n a a a m TA Adjusting Float Posittion Recharging the Hand Pump While At Pressure as DNS DS CD NO N ha A ID A A A kA A kA A LA ID 2 k K K K il Contents continued Discharging the Hand Pump While At Pressure 4 14 Returning to Atmosphere 4 15 Valve Operating Procedure RUSKA 2485 950 4 15 Recharging the Hand Pump While at Atmosphere 4 17 Generating Pressures to 20 000 PSI 1400 Bar 4 17 Press rizing the Systemi esiasio naiinitan raitinn asii 4 17 Adjusting Float Posittion een 4 17 Recharging the Hand Pump While at Pressure
107. t The installation kit part number 2485 202 or 2485 203 contains all the necessary hardware such as wrenches seals and piston cylinder cleaning tools for operating of the RUSKA 2485 deadweight gauge See Appendix B for detail of the setup kit RUSKA 2485 Piston Cylinder Assemblies The piston cylinder assemblies used in the RUSKA 2485 are manufactured from high grade tungsten carbide The precision surfaces of each piston cylinder assembly are finish lapped and matched to provide optimum performance with minimal leakage over a wide pressure range The high level of performance achieved with the RUSKA 2485 piston cylinder assemblies is such that only three ranges are required to cover the total pressure range of the instrument while maintaining optimum accuracy Various intermediate ranges are available however to suit specific applications Technical Description 3 Instrument Features and Functions The effective area of each piston cylinder assembly is adjusted such that for a given load in kilogram denominations it will generate nominal pressure increments in either English units psi or S I units bar All assemblies are permanently identified with a pressure unit increment designator and a unique serial number for traceability An example of the pressure unit increment designator for one of the English piston cylinder assemblies 1s P200 The P designates the unit of measure psi and 200 indicates the nominal increment For each k
108. t is required to produce the desired force F on the piston For English Units K T 2 1 2 Pon Pan _ Par where 2 acceleration due to standard gravity 980 665 cm sec Bi acceleration due to local gravity in cm sec Dp density of air in g cm see Equation A 4 Pa density of apparent mass for Apparent Mass versus Brass 8 4 g cm for Apparent Mass versus Stainless Steel 8 0 g cm When selecting masses from the calibration report assure that the values selected are in the same Apparent Mass unit of measure that was used to calculate the K or K values The apparent mass Column 9 is obtained from M FK where M F K For SI Units where 8 pP air Fim Calculations A Explanation of Pressure Calculation Worksheet apparent mass record in Column 9 force required on piston as found in Column 8 multiplier which was determined by previous equation K 1 g 1 p p acceleration due to local gravity in m sec density of air in g cm see Equation A 4 density of apparent mass for Apparent Mass versus Brass 8 4 g cm for Apparent Mass versus Stainless Steel 8 0 g cm When selecting masses from the calibration report assure that the values selected are in the same Apparent Mass unit of measure that was used to calculate the K or K values The apparent mass Column 9 is obtained from where M K M FK apparent mass versus brass record in Column 9 forc
109. t to Pa absolute by adding barometric pressure e g P 101325 Nitrogen Density SI Units 6 9 MPa to 100 MPa To calculate the density of Nitrogen at pressures from 6 9 MPa gauge to 100 MPa use the following equation DENSITY kg m 6 573 11 016 P 0 055087 P where P PRESSURE in MPa absolute if P is in gauge convert it to MPa absolute by adding barometric pressure e g P 101325 Zero Air Density SI Units 0 MPa to 20 7 MPa To calculate the density of Zero Air at pressures to 20 7 MPa use the following equation DESNSITY kg m 1 17 E 05 x P where P PRESSURE in Pa absolute if P is in gauge convert it to Pa absolute by adding barometric pressure e g P 101325 Helium Density SI Units 0 to 6 9 MPa To calculate the density of Nitrogen at pressures from 0 01 MPa gauge to 6 9 MPa use the following equation DENSITY kg m 1 585 E 06 x P where P PRESSURE in Pa absolute if P is in gauge convert it to Pa absolute by adding barometric pressure e g P 101325 Helium Density SI Units 6 9 MPa to 100 MPa To calculate the density of Nitrogen at pressures from 6 9 MPa gauge to 100 MPa use the following equation DENSITY kg m 0 3136 E 01 1 508 P 3 886 E 03 P2 where P PRESSURE in MPa absolute if P is in gauge convert it to MPa absolute by adding barometric pressure e g P 0 101325 A 6 Calculations Conversion Factors A Conversion Factors Table
110. the particular system segment 2 Rotate the hand pump clockwise until pressure begins to build If the rotation is greater than one quarter turn of the hand pump spindle there is a significant amount of air trapped in that segment 3 Remove the air from that segment before proceeding to the next segment The hand pump segment should be tested first If air is trapped in the hand pump it can be removed by loosening the bleed screw located on top of the hand pump housing in front of the pressure monitor Once the hand pump segment is free of air continue to the next segment which will consist of the hand pump segment plus for example the high pressure end of the intensifier RUSKA 2485 950 only Note that in this example if the intensifier has not been recharged as described in Chapter 4 Valve Operating Procedure for RUSKA 2485 950 it will appear that there is a large amount of air trapped in the system as the intensifier plunger is pushed to the recharge travel limit Once the intensifier is fully recharged recharge the hand pump and repeat the test Air trapped in other segments may require loosening certain fittings to bleed the air from the system 5 5 RUSKA 2485 Users Manual If most of the air has been removed but that which remains eludes discharge the system should be pressurized to several thousand psi over night During this period air trapped in the system will go into solution with the oil After this time period has p
111. the piston cylinder assembly This vertical position is often referred to as the horizontal plane of reference as all positions within the system n the same horizontal plane will have the same pressure This position is usually selected for convenience so that the effects of fluid buoyancy on the submerged portion of the piston and the pressure head correction for that position cancel and can be ignored This position is located at the physical bottom of a piston of uniform geometry For other piston styles where for example there is an enlargement on the bottom of the piston such as a retaining nut the reference plane position is somewhat below the physical bottom of the piston assembly at a position where the bottom of the assembly would be if the nut was the same diameter as the piston while conserving the volume Pneumatic Pressure Gradients In the same way as pressure heads are generated in a hydraulic system they also are prevalent in pneumatic systems The two important differences between hydraulic and pneumatic system pressure heads are that the magnitude of the pneumatic system corrections tend to be significantly less at lease at lower pressures than n a hydraulic system and that unlike the relatively constant hydraulic head the magnitude of the gas head changes significantly with pressure due to the relative high compressibility and resulting density increase associated with gases For further information on pneumatic press
112. the set up kit with the barbed connection on the oil drain line This will allow the waste hydraulic oil to be piped to an acceptable refuse container Please dispose of the waste oil properly NEVER REUSE waste hydraulic oil Fill Pump Assembly RUSKA 2485 930 amp RUSKA 2485 935 The fill pump is a motorized pump which facilitates the bleeding of external lines or device under test The pump is powered from the drive motor assembly A power pigtail extends from the bottom of the drive motor housing and plugs into a power inlet receptacle on the back side of the pump assembly Fixed Support Leg The instrument platform is supported by three legs One of these legs is fixed and is not adjustable This fixed support leg is positioned directly below the main pressure housing to prevent deflection of the instrument base when the load is applied This lack of deflection in the instrument base provides more stable adjustment of the instrument level Auxiliary Support Leg Should the operator attempt to move the instrument while a mass load is applied the auxiliary support leg will prevent the instrument from tipping over Adjustable Support Legs The model RUSKA 2485 incorporates two adjustable support legs positioned at the front and rear of the right side Adjustment of these legs may be required upon installation of the instrument and according to the level vial attached to the instrument base each time a significant change is made to the
113. tion Introduction The RUSKA 2485 deadweight gauge is available in two configurations a low pressure version RUSKA 2485 930 rated to 20 000 psi 1400 bar and a high pressure version RUSKA 2485 950 rated to 72 500 psi 5000 bar The high pressure version incorporates an integral intensifier for operation above the 20 000 psi 1400 bar Operation of the intensifier requires the use of additional valves and plumbing and a slightly different valve operating procedure for generating pressures The following sections describe the general operation of the instrument in terms generic to both high pressure and low pressure versions as well as specific valve operating procedures for generating pressure with each version of the instrument Precautions N Warning Pressurizing vessels and associated equipment are potentially dangerous The apparatus described in this manual should be operated only by personnel trained in procedures that will assure safety to themselves to others and to the equipment Safe and proper operation of this system requires that the operator have a thorough knowledge of the operation of the system and follows a strict procedure for pressurizing and depressurizing the system to prevent damage to the delicate internal components and to prevent injury to personnel Operation of the hand pump and valves must be performed in such a way as to maintain control of the system at all times At the conclusion of operation of the
114. to installing the temperature probe Fill Pump Assembly RUSKA 2485 930 The fill pump is a motorized pump which facilitates the bleeding of external lines or device under test Before using the fill pump check the reservoir level to assure an ample amount of fluid is available Next loosen the reservoir lid to allow air into the reservoir The reservoir valve and the system valve must be open Energize the pump by toggling the control switch on the left hand side of the drive motor assembly Open a line or bleed a fitting at the high point of the circuit to allow the escape of trapped air Operating the fill pump with the system and reservoir valves closed should do no harm to the system however operating the pump for more than 2 3 minutes with the valves closed will warm the hydraulic oil above ambient temperature and is therefore not recommended The pump may be damaged if the reservoir is allowed to run dry Preparation for Use The RUSKA 2485 is shipped from the factory with a small amount of pressure trapped in the system After completing the installation according to Chapter 4 Setting Up the Instrument Platform follow the step by step procedure described below to safely remove the pressure from the instrument and prepare the instrument for use 1 Rotate the Reservoir Source Valve on the rear of the instrument to the internal reservoir position 2 Thread the four pump handles carefully into the hand pump spindle nut on the f
115. ts for accurate generation of any pressure within the range of the instrument The features and functions of the system components are described below Instrument Features and Functions The instrument features listed in Table 3 2 can be found in the figures listed by each feature Refer to the sequence number shown in Table 3 2 to locate the feature in the appropriate figure Refer to Table 3 1 for a functional description of each feature Table 3 1 Instrument Platform Functional Description Functional Description Instrument Cover The instrument cover can be removed to access the internal hardware for maintenance or repair The left and right cover panels are secured by thumb screws at the edges of the panels on the front top and rear of the instrument Mass Loading Table Assembly and Chapter 3 Installation Kit for further discussion of the mass loading table assembly Reservoir valve A Reservoir valve A is opened to recharge the hand pump and closed to provide a positive cutoff to the reservoir to allow pressurization of the instrument 002 Mass Loading Table Assembly The mass loading table assembly secures the piston cylinder assembly in the main pressure housing and transmits the load of the mass set to the piston A piston cylinder assembly installed in the main pressure housing is protected from damage due to pressure release while under load as well as when the load is removed with pressure applied by thrust bearings
116. uarter turn counter clockwise and then carefully clockwise to restore the pressure or float position and to remove any spindle nut backlash This will prevent the pump plunger from creeping out of the pump housing which could result in erroneous pressure readings Recharging the Hand Pump While At Pressure On occasion the hand pump will reach the full clockwise travel limit preventing further pressurization The hand pump may be recharged while the system remains at pressure l To recharge the hand pump while the system is at pressure verify that pressure valve B is open and note the system pressure indicated on the pressure monitor Close pressure valve B and carefully rotate the hand pump spindle counter clockwise until the piston is at the lower travel limit and the pressure monitor indicates between zero and 500 psi 35 bar Open reservoir valve A and continue rotating the hand pump spindle counter clockwise until the pump position indicator approaches the counter clockwise travel limit Rotate the hand pump spindle clockwise one quarter turn and close reservoir valve A Carefully rotate the hand pump spindle clockwise to generate pressure Once the pressure monitor indicates the same pressure noted earlier slowly open pressure valve B Discharging the Hand Pump While At Pressure When reducing pressure in the system the pump may reach the counter clockwise travel limit before the desired pressure is obtained To allow furth
117. ument platform A Warning The operator of any pressurized equipment must always be aware of the condition and status of the equipment to avoid the risk of damage and personal injury A Caution Reservoir valve A and pressure valve B perform different functions in the RUSKA 2485 930 and RUSKA 2485 950 instrument platforms The valve operating procedures for the RUSKA 2485 930 should not be used when operating the RUSKA 2485 950 The following procedures reference the valve positions open and closed The operator must manipulate the valves in such a way that their status can easily be determined When the procedure refers to opening a multi turn valve the valve should not be allowed to remain in the full open state rather if it has been fully opened it should then be closed approximately one half turn If a valve is positioned at any place between nearly full open and approximately one half turn open the operator can assess the open status of the valve by simply rotating the handle in either direction If the valve has been left in the full open position it will be difficult to determine whether the valve is open or closed If the valve is closed and the operator believes it to be open permanent damage to the valve seat can occur if the stem is over torqued 4 15 RUSKA 2485 Users Manual LOW 72 KPSI 5000 BAR ee 20 KPSI 1389 BAR PRESSURE y N Max TEST PORT PISTON RESERVOIR SELECTION VALVE
118. ure head corrections refer to the tables included in Appendix A Reference Pressure Head 2 8 For very low pressure devices referenced to atmosphere and some low pressure differential devices where both the test port and the reference port are pressurized a further correction may be necessary to account for a difference in the reference pressure acting on the test device and the standard For a device referenced to atmosphere and positioned above the standard the atmospheric pressure acting on the reference port of the test device will be less than that acting on the standard For normal air density this correction equates to approximately 5 2 x 10 psi per foot 1 18 x 10 KPa per meter The correction is in the opposite direction of the system pressure head correction but is of a constant magnitude and hence will be most significant at the lower calibration pressures The reference pressure head correction can be simplified by assuming nominal equality of the density of the system gas and the reference pressure gas atmosphere Then using a system gas density for a gauge pressure taken from a chart for absolute pressures the result will likely be beyond the performance of all but the most sensitive devices Piston Pressure Gauge 2y Pressure to Mass Equation Float Position The optimum operating position of a piston pressure gauge is known as mid float This position near mid stroke of the piston is the calibrated position and t
119. urements Appendix A includes tables and equations for computing air density based on these parameters Even though the environmental conditions vary continuously the range is usually relatively small Often average barometer temperature and relative humidity values are used for calculating air density and the typical environmental variations are accounted for in the estimate of uncertainty Some piston pressure gauges incorporate a reference chamber for evacuating much of the air surrounding the load on the piston In this absolute mode of operation the air remaining in the reference chamber usually has an insignificant buoyant effect on the masses although the actual pressure typically near 100 mTorr or 0 002 psi may be a substantial portion of the total pressure and should be added to the piston pressure Further because the buoyant force is not significant the true mass values should be used It is important to note that under extreme evacuation there may be additional considerations as well as the potential for a reduced level of performance and an increase in uncertainty Refer to reference number 4 for further discussion of apparent mass Piston Pressure Gauge 2y Measurement Considerations Combined Gravity and Air Buoyancy Correction If the effects of varying ambient conditions are within acceptable limits as determined by an error budget it becomes convenient to combine the air buoyancy and gravitational corrections
120. wer end of the test port manifold If the seal is excessively worn or leaks when pressurized it should be replaced before continuing To replace the seal carefully rotate and slide the old seal off of the stem and discard DO NOT USE ANY SHARP OBJECT TO REMOVE THE SEAL Lubricate the new seal part number 72 33 with a small amount of the deadweight gauge oil and carefully slide it onto the manifold stem The flared end of the seal should be oriented toward the bottom of the manifold stem N Caution Any device or system connected to the test port manifold or other test port on the RUSKA 2485 must be clean and free of contamination to prevent the damage to the precision deadweight gauge components If the deadweight gauge is to be used to calibrate devices that are not known to be clean an external filter trap such as 2436 800 can be used up to 40 000 psi 2800 bar Use of a fine mesh filter to trap minute particulates can result in reduced sensitivity of the deadweight system To obtain maximum sensitivity and the highest level of accuracy in a pressure measurement the device under test must be clean Connect the device under test and any required adapters to the test port manifold refer to Figure 4 4 Rotate the hand pump clockwise to adjust the oil level in the auxiliary pressure housing to within approximately 2 mm of the top Guide the lower stem of the manifold into the auxiliary pressure housing Open the appropriate valve to the r
121. ypes of Piston Pressure Gauges The piston pressure gauge is sometimes regarded as an absolute instrument because of the principle by which it measures pressure An absolute instrument s defined here as one capable of measuring a quantity in the fundamental units of mass length time etc It may be suggested that only certain types of piston pressure gauges qualify in this category PRESSURE IN glg01 eps Figure 2 1 Simple Cylinder PRESSURE IN glg44 eps SECONDARY PRESSURE PRESSURE IN glg45 eps Figure 2 3 Controlled Clearance Cylinder Figures 2 1 2 2 and 2 3 illustrate the three most common types of cylinder arrangements When the simple cylinder of Figure 2 1 1s subjected to an increase in pressure the fluid exerting a relatively large total force normal to the surface of confinement expands the cylinder wall near Point A and results in an elastic dilation of the cylinder bore As the pressure is increased the cylinder expands and the effective area increases The change in effective area is usually a linear function of the applied pressure The piston also suffers distortion from the pressure of the operating fluid but to a much lesser extent than the cylinder It is evident the that the simple cylinder of Figure 2 1 would be inadequate for a primary piston pressure gauge unless some reliable means of predicting the change in area were available Piston Pressure Gauge 2 Measurement Considerations The
122. yy si sn S8rp VASNA Appendix B Setup Kit Bills of Material Setup Kit 2485 202 for RUSKA 2485 930 950 Table B 1 Setup Kit 2485 202 for RUSKA 2485 930 950 of measure 2411 co 010 RTD PRT ree T 1 8 NPT X 3 16 1 00 EACH a 246540 100 PISTON amp CYLINDER CLEANING KIT amp CYLINDER CLEANING KIT 1 00 1 00EACH 2485 102 001 LOW RANGE CYLINDER CLEANING 1 00 EACH aoe er _ 1D02 a MANUAL 1 Um 100EACH 2485 920 920 MIRRORBLOCK BLOCK 1 00 100EACH w FLOAT POSITION 2485 KIT 001 ADAPTER KIT 1 00 EACH FOR AUXILIARY CONNECTOR BLOCK PT 216 Ter 1 AMP SLOW BLOW SIZE 3AB 2 00 EACH pee ae 5470437 700 437 DRIVE BELT DRIVE BELT ME 1 00 100EACH FOR ROTATION SLEEVE ROTATION SLEEVE 594 703 008 O RING VITON 3 16 I D X 1 16 CROSS 6 00 EACH an EXTENDED RANGE SECTION 934 703 117 O RING VITON 13 16 X 3 32 CROSS 2 00 EACH FOR P Cs OTHER THAN SECTION EXTENDED RANGE 54 703 14 O RING VITON 1 2 I D X 1 16 CROSS 6 00 EACH s EXTENDED RANGE misis 12 7233 000 SEAL 1 4 X 1 2 PLOYPAK T 1 4 X 1 2 PLOYPAK 4 00 400EACH FOR CONNECTOR BLOCK CONNECTOR BLOCK 86 802 TUBING CLEAR PLASTIC 3 8 OD X 5 00 FEET WASTE MEDIA DRAIN LINE C T W X 1 4 ID 94 607 607 WRENCH HEX KEY 1 8 HEX KEY 1 8 1 00 I 100EACH 94 608 WRENCH HEX KEY 3 32 1 00 EACH 2485 Users Manual Table B 2 Setup Kit 2485 202 for RUSKA 2485 930 950 continued Part Number Description oye or of Measure 94 617 WRENCH P

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