Gas Flow Standards
Contents
1. mealblece molbeoe gt gt lt Flow Calibration System TABLE OF CONTENTS INTRODUCTION GENERAL FEATURES 3 PUTTING TOGETHER 8 A molbloc molbox FLOW CALIBRATION SYSTEM molbox FLOW TERMINALS molbloc LAMINAR 13 FLOW ELEMENTS SPECIFICATIONS TABLE OF CONTENTS amp INTRODUCTION INTRODUCTION In the early 1990s DHI recognized the growing need for a new calibration tool for low gas flows To support increasing requirements for lower measurement uncertainties and documented traceability of flow measurements at the process level a transfer standard combining high performance with portability and ease of use was needed DHI developed the molbloc molbox flow calibration system in response to this need Based on a new patented laminar flow element design and applying today s modern measuring mathematical modeling data processing and manufacturing techniques molbloc molbox introduced a new level of performance and convenience in low flow standards molbloc molbox has rapidly gained wide acceptance in a variety of fields semiconductors fiber optics pharmaceuticals environmental monitoring energy production reference gas blending research and standards laboratories as the reference of choice in assuring the integrity of low flow measurements molbloc molbox covers the flow range from less than 1 sccm to more than 100 slm with accuracy to 0 2 of reading in a variety of gases A 12. e Overpressure monitoring and self defense system Downstream Pressure Upstream Pressure Purge Time Remaining molbox Purging Function Display Also included are advanced functions such as e Averaging over time with adjustable time period and standard deviation calculation e Hi Lo monitoring e Flow totalizing with adjustable time period e Simultaneous display in two different flow units of measure e MFC control and measurement with flow and FS conversions molbox1 option only e Password protected data security Current Flowing Flow Rate Gas i ar aaah ae Rect Bhat HE fee ad fae i Rev ah fs Total TOr Flow Flow Time Flow Totalizer Function Display As molbox s embedded software is stored in FLASH memory keeping molbox current with all the latest features is easy and cost free Periodic software improvements and upgrades are placed on DHI s world wide web site www dhinstruments com and can be downloaded and installed by the user at no charge STANDARD COMMUNICATIONS INTERFACES Every molbox includes RS232 and IEEE 488 interfaces for communication with a host computer A second RS232 port COM2 is included for pass through communication with another RS232 device RS232 COM1 COM2 T mal TEEE 488 Rear Panel Interface Connections The interfaces are supported by a complete set of ASCII command strings allowing all molbox measurements and functions to be accessed remotely All asp
3. REFERENCE FLOW MONITOR the same molblocs but provide different measurement uncertainties size and cost Generally molbox1 is oriented towards applications in which minimizing measurement uncertainty and stability over time are the most important requirements molbox RFM has slightly lower performance but is also lower in cost and more compact execute the molbloc mass flow equation and provide real time mass flow measurements e Local Operator Interface A 4 x 4 keypad and 2 x 20 display provide local user control over molbox operation allowing a wide variety of functions to be performed e Remote Interfaces RS232 and IEEE 488 interfaces support host computer communications using simple ASCII string commands A second RS232 interface COM2 is available for pass through communications to another device e Advanced Measurement Functions molboxes support advanced measurement functions such as averaging flow totalizing hi lo and others e Analog MFC Support molbox1 only An optional board with rear panel connector sets and reads both voltage and current in support of analog mass flow controller MFC testing A B CD H 1 Ready Not Ready indication based on user defined stability test 2 Current rate of flow through the molbloc and unit of measure 3 Gas currently flowing 4 Special functions display line select Average Rate Hi Lo Totalize Second Flow Unit Deviation Freeze or Clean K Function Set the de
4. Carbon Tetrafluoride Hexafluoroethene FLUORO CARBONS Trifluoromethane Air Carbon Dioxide Carbon Monoxide Nitrous Oxide Octafluorocyclobutane Oxygen N A 20 000 13 800 22 000 12 700 130 000 42 000 12 000 molbloc RANGES TABLES LEGEND 1E1 thru 3E4 A bold value indicates that the maximum flow is limited by the maximum Reynolds number value of 1 200 which is reached before the normal differential pressure range is reached In that case the second value gives the minimum flow for which measurement uncertainty is 0 2 0 5 with molbox RFM of reading With the molbox RFM microrange option this value is divided by 10 With molbox1 on size 3E4 the 0 2 is 0 3 Where there is no value in the table this indicates that the maximum Reynolds number is reached before the differential pressures reaches 5 kPa therefore calibration with that gas is not useful TES A bold value indicates that the maximum flow is limited by the maximum Reynolds number value of 1 200 which is reached before the normal 1E5 differential pressure range is reached In that case the second value gives the minimum flow for which measurement uncertainty is 0 5 of reading both molbox1 and molbox RFM With the molbox RFM microrange option this value is divided by 5 Where there is no value in the table this indicates that the maximum Reynolds number is reached before the differential pressure reaches 1 kPa
5. OCG 100 and 110 Q 0 01 stability better than 25 ppm year FLOW MEASUREMENT Measurement Update Rate Range Resolution Linearity Standard Microrange Option Repeatability Standard Microrange Option Precision Standard Microrange Option 1 second 0 to molbloc full scale depending on molbloc designation gas and molbloc pressure dependent calibration type see molbloc Ranges Tables pp 15 and 16 00015 yaks 0 15 of reading 0 015 FS under 10 Not available 0 05 of reading 0 005 FS under 10 Not available 0 16 of reading 0 016 FS under 10 Not available Predicted Stability2 One Year Standard Microrange Option 0 1 of reading 0 01 FS under 10 FS Not available CO orks FS 0 23 7 01 reading 0023 FS under 0 75 FS 0 23 of reading from 1 to 10 FS 0 023 FS under 1 FS FS 0 1 of reading 0 01 FS under 10 FS 0 1 of reading from 1 to 10 FS 0 01 FS under 1 FS FS 0 25 of reading 0 025 FS under 10 FS 0 25 of reading from 1 to 10 FS 0 025 FS under 1 FS 0 15 of reading 0 015 FS under 10 FS 0 15 of reading from 1 to 10 FS 0 015 FS under 1 FS Measurement Uncertainty N and Any molbox Supported Gas for Which the molbloc in Use is Calibrated Standard 3E4 molbloc 1E5 molbloc Microrange Option 102 7 01 reading 0 02 4 Founder 10 7a ho 0 3 o
6. off the shelf solution to put the molblocs into service and connect to a device to be tested COMPASS application software is available to complete a fully automated test system DUT and considering the molbloc and DUT differential pressure requirements b Select the molbloc size s see tables on pp 15 and 16 A molbloc s flow range varies with the molbloc s size pressure dependent calibration type and the gas flowed Note that all molblocs measure flow from zero to full scale and their measurement uncertainty is a percent of reading above 10 full scale 1 for molbox RFM with the microrange option c Select the molbloc special gas calibrations All molblocs are calibrated with nitrogen N but can measure the flow of any molbox supported gas With non N gases for lowest measurement uncertainty and documented traceability a calibration with the gas must be specified 3 Select One or Several molstic molbloc Mounting Systems see molstic brochure If Needed molstics provide an engineered solution to the practical issues of connecting the molbloc to a regulated gas supply mounting the molbloc and mounting and connecting to a device under test 4 Select molbloc molbox Applications Software If Needed COMPASS for molbox see COMPASS brochure COMPASS for molbox software works with molbloc molbox to create a turnkey full function automated system for calibrating and testing a wide variety of flow measuring an
7. second update rate makes real time measurement and test instrument adjustment with a true flow standard possible for the first time Compact and readily transportable molbloc molbox can be operated locally from the full feature front panel or remotely over its RS232 and IEEE 488 interfaces molbloc molbox configurations and accessories support a wide variety of flow testing and measurement applications molbloc molbox can be integrated into systems for on line checking of process instruments easily transported for use as an on site audit or check standard and combined with accessories to set up a complete automated flow calibration bench molbloc molbox systems test and calibrate a wide variety of flow devices including thermal MFCs rotameters turbine meters bubble meters and others The pages that follow describe molbloc molbox GENERAL FEATURES Pages 3 to 7 describe molbloc molbox technology and summarize some of the important features that make molbloc molbox a unique flow calibration tool PUTTING TOGETHER A _ molbloc molbox SYSTEM Pages 8 and 9 illustrate some typical molbloc molbox configurations and provide instructions for putting together a molbloc molbox system to fit your specific needs molbox FLOW TERMINALS Pages 10 to 12 detail the two molbox flow terminal models available molbloc LAMINAR FLOW ELEMENTS Pages 13 to 16 cover the molbloc flow elements and calibration options available to cover different flow
8. therefore calibration with that gas is not useful LIST OF SYMBOLS molbloc LAMINAR FLOW ELEMENT P 2 mass flow upstream absolute pressure downstream absolute pressure ee 2 absolute temperature of gas N A The operating pressure range is greater than the vapor pressure value for this gas dynamic gas viscosity under P T conditions Pae s kg s Co geometry of molbloc flow path and m3 Pa Reynolds number dependence Pa Reynolds number Pa molecular weight of the gas g mol compressibility factor of the gas under Ik P T conditions universal gas constant EEN E kg mole k radius of the piston m molbloc LAMINAR FLOW ELEMENTS GENERAL Power Requirements Normal Operating Temperature Range Storage Temperature Range Vibration Weight Dimensions Microprocessor Communication Ports M Specifications mcalia e x1 85 to 264 VAC 47 to 440 Hz 18 VA max consumption 15 to 35 9C D0 o0 C Meets MIL T 28800D 6 8 kg 15 Ib max 52 CMW X 12 cm H X 30 cm D 12 6 in X 4 7 in X 11 8 in approx Motorola 68302 16 MHz RS 232 COMM RS 232 COM2 TEEE488 2 Reference Pressure Transducers RPTs Standard Microrange Option 2 x 700 kPa 100 psia with calibrated range of 550 kPa 80 psia Oscillating quartz crystal with mechanical bellows Not applicable Pressure Connections molbox and molbloc Quick connectors equivalent to Swagelo
9. ASS sets up device under test DUT records defines and associates test procedures with DUTs runs tests acquires reference and test data produces at COMPASS pii miles i peip Tgi Dpi aide Leip ATIE ma a Tiimer ca Dupi H E es ere Glens A mie Fj DUT Fic lak UT j j i i ara deta i pams ia ly KE 0 1 1 ie 1 20 H 1 I nm 5 271 mM oo a L pum 7M Wid 1 mo 37 17 ma gt E amet Pi ma COMPASS for molbox Main Run Screen GENERAL FEATURES standard and custom calibration reports All reference DUT and test data are collected and stored in standard delimited files that can be easily downloaded to other applications COMPASS is much more than a simple data acquisition and test sequencing tool It also includes specialized capabilities for data reduction in support of pressure and temperature dependent flow devices such as rotameters turbine meters and volume meters FROM A SIMPLE REFERENCE FLOW METER TO A COMPLETE CALIBRATION SYSTEM With a choice of two molbox models and a wide variety of accessories the exceptional flow measurement capabilities offered by molbloc molbox can be configured to fit a very wide variety of applications from a simple reference flow meter to a turnkey automated calibration system molbox RFM and a single molbloc configure a simple relatively low cost reference flow meter with measurement uncertainty of 0 5 of reading from 1 to 100 of full sca
10. PASS for molbox brochure CalTool for molbloc PC based software for calibration support of molblocs Allows molbloc calibrations to be adjusted by linear fit to agree with another flow standard with a given gas at a given operating pressure Training A three day training course for molbloc molbox operation is conducted regularly at the DH Instruments a Fluke Company Arizona facility On site training can also be arranged molbox RFM features include Flow measurement uncertainty of 0 5 of reading Microrange option to reduce measurement uncertainty under 10 of molbloc full scale Micromachined silicon piezoresistive pressure transducers Very compact presentation Lower cost than molbox1 ORDERING INFORMATION Description molbox RFM Part Number FAM0005 STANDARD DELIVERY Each molbox RFM is delivered complete with Power cord Tilt up front feet molbloc to molbox pressure line with quick connectors 2 ea molbloc to molbox electrical connection cable 1 ea Utility software disc User s manual Calibration report documenting traceability to the United States National Institute of Standards and Technology NIST Purpose OPTIONS Description Microrange option Part Number 02 Add 10 kPa 2 psi differential pressure transducer to improve resolution and lower uncertainty under 10 of molbloc full scale OPTIONAL ACCESSORIES Rack mount kit RPM3 molbox RFM P N 401465 Standard 19
11. abilization chambers to the molbox pressure lines Two platinum resistance thermometers PRT are embedded symmetrically in the molbloc body to measure its average temperature The molbloc is equipped with an EEPROM to store molbloc and PRT calibration coefficients The EEPROM information along with the resistance of the PRTs is read over the molbox 15 pin data cable connection All wetted molbloc surfaces are electroplished to a 0 15 u Ra to avoid contaminant accumulation in the flow path and molblocs are assembled under a class 100 clean hood Small molbloc in Case 5E3 and Lower molbloc Cutaway molbloc RANGES molblocs sizes are designated by a number relative to their nominal flow impedance The nominal impedance results in nominal flow ranges when flowing nitrogen gas with 250 kPa absolute 36 psia upstream pressure and 50 kPa 7 5 psid differential pressure across the molbloc In practice the molbloc flow range may be quite different from the nominal flow range The difference comes from differences in density and viscosity between gases and from different molbloc operating pressure calibration options Available molbloc sizes and ranges with various gases by calibration type are listed in the molbloc Ranges tables see pp 15 and 16 molbloc PRESSURE DEPENDENT CALIBRATION TYPES Different pressure dependent molbloc calibration options are offered to accommodate the operating pressure requir
12. as supply 3 molbox1 or RFM 9 Gas supply 10 molstic molbloc mounting system permanently installed upstream or downstream of AUMOSPNOTE device under test 5 Device under test e g rotameter or turbine meter D Test Calibration of Test Calibration of Thermal Mass Flow Controllers MFCs High Pressure Mass Flow Meters MFMs or MFCs 1 Host computer with RS 232 5 Device under test MFC 1 Host computer with RS 232 8 Regulator to protect molbox1 COM or IEEE 488 interface 6 Atmosphere or vacuum COM or IEEE 488 interface from overpressure 2 COMPASS for molbox 7 molbloc s 2 COMPASS for molbox 9 Flow adjusting valve calibration software l calibration software if DUT does not control flow 3 molbox1 8 Regulator molstic 3 molbox1 or REM 10 Device under test MFM 4 molbox1 MFC control option ue Gas Supply 4 molbloc s with downstream Or MEG cable 10 a molbloc mounting calibration 11 Pressure regulator to set system device under test upstream 5 Atmosphere pressure 6 Shut off valve 12 Gas supply 7 Filter PUTTING TOGETHER A SYSTEM M Putting Together a System The heart of a molbloc molbox system is the molbox1 mass flow terminal The molbox performs the da
13. d this brochure are subject to change without notice Locally By Products described herein are protected by US and international patents and patents pending molbloc molbox molstic and molbox RFM are trademarks of DH Instruments a Fluke Company COMPASS is a registered trademark of DH Instruments a Fluke Company LabVIEW is a registered trademark of National Instruments Corporation Swagelok and VCR are registered trademarks of the Swagelok Company Viton is a registered trademark of DuPont Company DH Instruments a Fluke Company D F l DH Instruments 4765 East Beautiful Lane USA Printed in USA 4 2007 3031052 B EN N Rev A Pub_ID 11238 eng Rev 01 Tel 602 431 9100 Fax 602 431 9559 dhi dhinstruments com www dhinstruments com 2007 DH Instruments a Fluke Company Bro No 6001 1 C 5
14. d controlling devices e CalTool for molbloc see CalTool brochure CalTool for molbloc software supports single P type see p 14 user recalibration of molblocs The molbloc can be adjusted to agree with another flow standard at a specific pressure molbloc M Flow Terminals The molbox is the center of a molbloc molbox flow calibration system The molbox performs the functions listed below For maximum versatility two different molbox models are available molbox1 and molbox RFM Both use e molbloc Pressure and Temperature Measurement The molbloc pressure ports are connected by flexible lines with quick connectors to the molbox s pressure transducers A data cable connects the molbloc platinum resistance thermometers to the molbox s ohmic measurement system and allows the molbox to read the molbloc EEPROM e Pressure Valving System Miniature valves inside the molbox support routines to zero the molbox pressure transducers run automated leak checks and purge when changing gases e Calculation of the Mass Flow Through the molbloc The molbox reads molbloc specific calibration coefficients off the molbloc s EEPROM The complete thermodynamic characteristics of the molbox supported gases are stored in molbox s non volatile memory Embedded software uses current pressure and temperature measurements the characteristics of the flowing gas and molbloc calibration coefficients to l 2 3 4 molbox RFM
15. ects of interfacing protocol and commands are thoroughly documented in the molbox Operation and Maintenance Manual LabVIEW drivers are available at no charge as program building blocks for National Instruments LabVIEW users TRACEABLE ACCURACY SUPPORTED BY PRIMARY GRAVIMETRIC STANDARDS molbloc molbox has the precision and stability over time required to be an excellent transfer standard To meet its full potential as a calibration tool it must be calibrated with primary standards traceable to national and international standards molbloc molbox s continuous reading capability and very high stability over time allow it to be calibrated using the only method that derives mass flow directly from the base units of mass and time In this method called gravimetric the amount of gas flowed over a period of time is weighed so its mass is known directly with no dependence on the imperfect knowledge of the gas s thermodynamic properties With the gravimetric method in exact agreement with the definition of a primary standard the uncertainty on mass flow is dependent only on the direct measurement of the base units of mass and time from which mass flow is derived DHI has developed a complete gravimetric calibration facility dedicated to molbloc molbox calibration The calibration system is maintained by the DHI metrology service and documented in a formal quality assurance program with a detailed uncertainty analysis To further inc
16. ements of different applications The options are outlined in the molbloc Pressure Dependent Calibration Types table see p 14 Large molbloc in Case 1E4 and Higher See pp 17 and 18 for complete molbloc molbox flow measurement specifications molbloc LAMINAR FLOW ELEMENTS ORDERING INFORMATION STANDARD DELIVERY Each molbloc is delivered complete with e Storage and shipping case Soft reusable VCR O rings and mounting instructions e Full mod low pressure Nitrogen N calibration A different N calibration and or calibration with non N gases must be ordered as separate line item e Calibration report documenting traceability to the United States National Institute of Standards and Technology NIST and reporting measured calibration data molbloc MASS FLOW ELEMENTS molbloc mass flow elements are ordered by size designation and part number see table DESIGNATOR DESCRIPTION PART NO 1E1 VCR V Q molbloc Mass Flow Element 401182 5E1 VCR V Q molbloc Mass Flow Element AQIS 1E2 VCR V molbloc Mass Flow Element 401184 2E2 VCR V Q molbloc Mass Flow Element 401187 5E2 VCR V Q 1E3 VCR V Q 5E3 VCR V Q 1E4 VCR V Q 3E4 VCR V Q 1E5 VCR V Q molbloc Mass Flow Element 401198 molbloc Mass Flow Element 400842 molbloc Mass Flow Element 400483 molbloc Mass Flow Element 401080 molbloc Mass Flow Element 401042 molbloc Mass Flow Element 401638 molbloc PRESSURE DEPENDENT CALIBRATION TYPES To accommodate dif
17. en 250 and 525 kPa absolute Special Gas Calibration Single P gt 5E1 molbloc specify gas 600212 and single pressure value between 250 and 525 kPa absolute molbloc LAMINAR FLOW ELEMENTS 14 15 INERT FLAMMABLE FLUORO CARBONS molbloc RANGES WITH LOW PRESSURE CALIBRATIONS e FULL MOD LOW PRESSURE e DOWNSTREAM e SINGLE P LOW PRESSURE molbloc SIZE AND FULL SCALE FLOW sccm Nitrogen Argon Helium Sulfur Hexafluoride Xenon Butane Ethane Ethylene Hydrogen Methane Propane Carbon Tetrafluoride Hexafluoroethene Trifluoromethane Air Carbon Dioxide Carbon Monoxide Nitrous Oxide Octafluorocyclobutane Oxygen 5E3 AND LOWER 1E4 AND 3E4 1E5 A _5850 2 303 7480 2 983 B 1600 0680 24000945 ji E 19010759 2800010 in ie 100 000 80 000 100 000 60 000 50 000 70 000 40 000 200 000 120 000 40 000 100 000 60 000 30 000 100 O00 60 000 30 000 FRONT VIEW M4 X 0 7 Thread 7 00 0 276 Deep 2 PI SIDE VIEW F lz U le aa i BOTTOM VIEW y ___ _ gt D molbloc Dimensions mm in molbloc LAMINAR FLOW ELEMENTS molbloc RANGES WITH HIGH PRESSURE CALIBRATIONS e FULL MOD HIGH PRESSURE SINGLE P HIGH PRESSURE molbloc SIZE AND FULL SCALE FLOW sccm Nitrogen Argon Helium Sulfur Hexafluoride Xenon Butane Ethane Ethylene Hydrogen Ww l m lt lt l me Methane Propane
18. ence gas mixes The laminar flow element s continuous uninterrupted reading capability makes it the ideal standard for checking or calibrating flow totalizing devices molbloc molbox can measure total flow without interruption over any time period MULTIPLE GAS SUPPORT molbloc molbox can measure the flow of a wide variety of gases These include the common inert gases as well as a variety of industrial process and calibration surrogate gases The complete thermodynamic properties unique to each gas are stored in molbox non volatile memory These are recalled and applied when the gas is selected The gas selection can be made directly at any time from the molbox front panel or by remote command An automated purge function clears the old gas from the molbox pneumatic circuit when using a new gas ADVANCED ON BOARD FUNCTIONS To complement its basic flow measuring capability and maximize the system s utility molbox supports a wide range of functions and special features These include operational features such as e Measure and display in 28 different units of mass and volume flow including user define units e Select from more than 18 different gases GENERAL FEATURES e Real time molbloc pressure and temperature displays e Adjustable display resolution e Full time stability dependent ready not ready indication e Automated purge routine for changing gases e Intelligent internal and external leak detection routines
19. f reading 0 03 FS under 10 FS 0 5 of reading from 25 to 100 FS 0125 o FS Under 25 FS Not available all ranges Precision Combined linearity hysteresis repeatability Stability Maximum change in zero and span over specified time period for typical molbox and molbloc used under typical conditions As stability can only be predicted stability for a specific molbox and molbloc should be established from experience 0 5 72 of reading 0 05 Fs Under 10 FS 0 5 of reading 0 05 FS under 10 FS 0 5 of reading from 5 to 100 FS 0 025 FS under 5 FS Microrange required 1E1 thru 3E4 0 5 of reading from 1 to 10 FS 0 005 FS under 1 FS 3 Measurement Uncertainty Maximum deviation of the molbox flow indication from the true value of the flow through the molbloc including precision stability and DHI calibration standard accuracy Measurement uncertainty is sometimes referred to as accuracy 18 SPECIFICATIONS melbloe melkex SOME USERS WORLDWIDE ENVIRONMENTAL QUALITY MONITORING Florida DEP Pennsylvania DEP Allegheny County Health Dept Indiana Dept of Environmental Management Dade County Division of Environmental Resource Management Gas DELIVERY SPECIALTY GASES Millipore Praxair Teledyne Brown Pneutronics Porter Instruments Qualiflow Aera Air Liquide Brooks Instruments MEDICAL Bio MEDICAL Abott Datex Ohmeda Johnson am
20. ferent requirements different operating pressure calibration options are available for molbloc Every molbloc has an N full mod calibration e Full mod low or high pressure calibrations are for cases in which the molbloc downstream and upstream pressures will be elevated above atmosphere usually the case if the device under test is downstream of molbloc The upstream molbloc pressure may vary within a range Two ranges are available high and low pressure e Downstream calibrations are for cases in which the molbloc downstream pressure is atmophsperic pressure usually the case if the device under test is upstream of the molbloc e Single P low or high pressure calibrations are a lower cost alternative to full mod calibrations for non N gt gases for cases in which the molbloc downstream pressures will be elevated above atmosphere Single P calibrations require that the molbloc always be used around the same pressure for that gas CALIBRATION OPERATING NOMINAL DIFFERENTIAL TYPE PRESSURE PRESSURE AT MAX FLOW Full mod Zo0UNO 525 Keo SOKE SPSI low pressure absolute 36 to 48 psia upstream of molbloc 925 10 SS La ol absolute 48 to 76 psia upstream of molbloc Full mod high pressure 50 kPa 7 5 psi Downstream Atmospheric pressure downstream of molbloc 80 kPa 12 psi Single P Any specified low pressure single molbloc non N2 gases only upstream pressure between 250 and 325 kPa absolute 36
21. his combination allows the temperature of the gas flowing through the molbloc to be known within better than 0 1 C SUPERIOR STABILITY OVER TIME The role of a transfer standard is to reliably transfer reference values from primary standards to other devices In filling this role the transfer standard s single most important characteristic is stability over time The stability over time of a molbloc molbox system is dependent on three parameters a the molbloc s laminar flow path geometry b the gas pressure measurement and c the gas temperature measurement The stability specification for a molbox1 based molbloc molbox system is 0 1 of reading per year This is made possible with a considerable safety margin by the fundamental mechanical stability of the molbloc flow path and pressure and temperature measurements that exceed the specification The molbloc s laminar flow path is the space between the molbloc body s central bore and the molbloc piston The path is defined using just two solid stainless steel parts In high range molblocs the piston is held rigidly in the cylinder by a patented holding system based on symmetrical elastic deformation of the centering holders In lower range molblocs in which the gap is quite small and even very small movement of the piston could alter the flow path significantly the piston is held by interference fit with the cylinder The flow path geometry is designed so that the gas passes
22. in rack mount kit for molbox RFM Panel is 3 5 in 2U high molstics Gas handling hardware and mounting system for molblocs See molstic brochure COMPASS for molbox PC based calibration software to automate calibrations with molbloc molbox See COMPASS for molbox brochure CalTool for molbloc For calibration support of molblocs Allows molbloc calibrations to be adjusted by linear fit to agree with another flow standard with a given gas at a given operating pressure Training A three day training course for molbloc molbox Operation is conducted regularly at the DH Instruments a Fluke Company Arizona facility On site training can also be arranged molbox FLOW TERMINALS 12 13 molbloc Laminar Flow Elements molblocs are laminar flow elements for use with molbox mass flow terminals The molbloc flow path is the longitudinal annular gap between a piston and a close fitting cylindrical bore in the molbloc body Different molbloc ranges are obtained by varying piston diameters within the same body to vary the size of the annular gap For high flow ranges size 1E4 and above a larger molbloc body with a larger cylindrical bore is used The molbloc piston is held in place by the symmetrical elastic deformation of piston holders and for smaller annular gaps by interference fit of the piston in the cylinder Quick connectors are used to connect the molbloc s upstream and downstream pressure st
23. in Laminar Flow molbloc molbox achieves unprecedented levels of stability and precision from the laminar flow principle by applying today s modern sensor mathematical modeling and data processing technologies to a flow element design so novel it has been granted US and international patent protection This combination improves knowledge of gas pressure and temperature provides a better definition of flow path and allows comprehensive real time flow calculation using the thermodynamic properties of the gas under actual flowing conditions ADVANCED PRESSURE AND TEMPERATURE MEASUREMENT TECHNOLOGY The uncertainty in flow measurements based on the laminar flow principle is very highly dependent on differential pressure gas density and viscosity and therefore the uncertainty in the pressure and temperature of the flowing gas molbloc molbox breaks new ground in gas pressure and temperature measurement 3 The pressure of the gas upstream P1 and downstream P2 of the molbloc flow element is picked off from pressure stabilization chambers and measured by two absolute pressure transducers GENERAL FEATURES located in the molbox flow terminal In molbox1 the transducers employ state of the art crystal oscillator technology providing 1 ppm resolution and 0 01 per year stability The upstream and downstream transducer readings are averaged to determine the absolute gas pressure The difference between the two press
24. k QM Series QM2 B200 Flow Connections molbloc Pressure Limits Max Working Pressure 1 4 in VCR 1E1 thru 3E4 1 2 in VCR IES 550 kPa absolute 80 psia Max Pressure W Out Damage 800 kPa absolute 115 psia Ohmic Measurement System Resolution Measurement Uncertainty Accuracy of 100 Q and 110 Q Reference Resistors Stability of 100 Q and 110 Q Reference Resistors Gases Supported 11 06 Flow Ranges CE Conformance Valve Driver Option 0 004 Q 0 02 of reading On aaa 0 005 per three years Nitrogen N gt Air Argon Ar Butane C4H 9 Carbon Monoxide CO Helium He Oxygen O3 Carbon Dioxide CO3 Carbon Tetrafluoride CF Ethane C2H6 Ethylene C H Fluoroform CHF3 Hexafluoroethane C5F Hydrogen H3 Methane CH3 Nitrous Oxide NO Octafluorocyclobutane C4Fg Propane C3Hs Sulfur Hexafluoride SF Xenon Xe 0 10 sccm to 0 100 slm see molbloc Ranges Tables pages 15 and 16 Available must be specified 8 12 V outputs Each output can sink 500 mA at 12 V max 1 Amp total MFC Control Option Analog Output Voltage Range 17 Voltage Accuracy Voltage Resolution Current Range Current Accuracy Current Resolution SPECIFICATIONS O to 6 000 VDC HOOFS 0 1 mVDC 4 to 20 mA ae QE Il Yo les 0 4 uA rmelimen gt RFT All specifications same as molbox1 unless specified otherwise 2 55 kg 5 6 lb max 22 5 c
25. le molbox1 with the MFC option molstics and COMPASS software make up a turnkey fully automated mass flow calibration bench COMPACT RUGGED AND TRANSPORTABLE molbloc molbox makes a very high performance mass flow standard easily transportable for the first time A molbox and one or several molblocs can safely be packaged and shipped or even hand carried from one location to another molbloc molbox can be used as an audit or check standard and as a field standard for on sight calibration or troubleshooting Its very high precision and stability also make it an ideal transfer standard for comparing primary standards at different locations molbox1 and molblocs Ready for Shipment rm lea A mM Hs o x Typical System Configurations 5 gt p lt 4 On Line Verification of Test Calibration of Process Flow Measurement Control Rotameters or Turbine Flowmeters 1 molbox1 or RFM mobile or 4 Connection to atmosphere 1 Host computer with RS 232 6 Flow adjusting valve permanently installed gas collector or device COM or IEEE 488 interface 7 molbloc s 2 Host communications under test 2 COMPASS for molbox 8 Regulator molstic optional 5 Connection to device under calibration software ne 3 molbloc mobile or test or g
26. loc can be used to calibrate a wide range of devices For example a 5 sIm molbloc used with molbox1 to calibrate 1 FS devices has a 5 1 or better measurement accuracy ratio with any device whose range is between 500 sccm and 5 slm With molbox RFM 0 5 of reading measurement uncertainty from 1 sccm to 10 slm can be achieved using only two molblocs molbloc molbox s rangeability reduces system complexity and original cost as well as on going recalibration costs Measurement Uncertainty 0 050 FS 0 020 FS 0 005 FS 0 005 FS 0 020 FS 100 0 050 FS molbloc Flow Measurement Uncertainty GENERAL FEATURES CONTINUOUS REAL TIME READING The mass flow through a laminar flow element at any moment in time is directly proportional to the pressure drop across the element Unlike systems based on rate of volume or rate of pressure change the measurement of flow through a laminar element is not time based This allows molbloc molbox to deliver flow readings as frequently as once per second with the system s full precision and minimum uncertainty Real time reading makes it possible to collect test or calibration data without having to wait for measurement cycles to complete or reset Real time reading provides instantaneous feedback on the effect of adjustments made to a device under test Real time reading also allows molbloc molbox to be used in active measurement applications such as blending refer
27. m lt 6 cm x 20 cm D S290 x n 7 ln approx 2 x 550 kPa 80 psia piezoresistive silicon 12 5 kPa 1 8 psid piezoresistive silicon Not available Not available melba 1 MFC Control Option Analog Input Voltage Range Min Max Measurable Voltage Voltage Accuracy Voltage Resolution Current Range Current Accuracy Current Resolution Valve Test Point Range Valve Test Point Accuracy Valve Test Point Resolution O to 5 000 VDC 0 25 6 000 VDC ss O05 Ye les 1 mVDC 4 to 20 mA S005 TS 0 4 uA 2to 15 VDC in reference to 15 VDC 0 25 9 ES 2 5 mVDC PRESSURE MEASUREMENT Type Range FS Standard Microrange Option Resolution Standard Microrange Option Oscillating quartz crystal with mechanical bellows Digiquartz O to 550 kPa absolute 0 to 80 psia Not available 0 7 Pa 0 0001 psi Not available Measurement Uncertainty One Year Absolute Pressure Differential Mode with Tare Microrange Option 0 02 FS 5 Pa 0 0007 psi 0 02 AP Not available TEMPERATURE MEASUREMENT Type Range FS Resolution Measurement Uncertainty On Board Reference Resistor mole RFM Not available Piezoresistive silicon O to 12 5 kPa differential 1 8 psid 5 5 Pa 0 0008 psi 0 14 Pa 0 00002 psi 0 05 FS 20 Pa 0 003 psi 0 05 AP 0 625 Pa 0 0001 psi 0 14 AP molbloc PRTs with molbox Ohmic Measurement System O to 40 C OO EV
28. p Johnson Boston Scientific Scimed Edstrom Industries Merck Datascope Genzyme Protein Design Labs NATIONAL MEASUREMENT LABORATORIES CMI Czech Republic LNE France NRC Canada TX Natural Resource Conservation Commision US EPA Redwood Microsystems Unit Kinetics St Jude Medical SmithKline Beecham Westaim Biomedical PTB Germany CMS Taiwan NIST USA OFMET Switzerland NUCLEAR POWER Niagara Mohawk TU Electric Virginia Power American Electric Power Baltimore Gas amp Electric Detroit Edison PECO Energy Pennsylvania Power amp Light Public Service Electric amp Gas PETROCHEMICAL R amp D Instituto Mexicano de Petroleos Mobil Rohm amp Haas Union Carbide Dow Chemical Ethyl Petrol Additives Amoco Arco Chemical SEMICONDUCTOR MICROELECTRONICS FIBER OPTICS Advanced Micro Devices Cherry Semiconductor Intel Philips Alcatel Cirrent Intersil SGS Thompson Allegro Microsystems Corning Lucent Spectran Analog Devices Eastman Kodak Mitel 3M Applied Materials Epitaxx Motorola Varian Atmel IBM National Semiconductor OTHER Aerometrologie Gelman Sciences Laminar Technologies Peus Babcock and Wilcox General Motors Litton Life Support Pratt amp Whitney Bechtel Nevada Honeywell Microswitch Lockheed Martin Raytheon Brigham Young Univ Horiba NASA US Army Concoa Intertechnique North Coast Calibration US Airforce Due to a policy of continuous improvement all specifications contained in Represente
29. ption 8 switchable 12V outputs ORDERING INFORMATION Description molbox1 Part Number FAM0004 STANDARD DELIVERY Each molbox1 is delivered complete with Power cord Tilt up front feet molbloc to molbox pressure line with quick connectors 4 ea molbloc to molbox electrical connection cable 2 ea Rubber feet caps 4 ea Utility software disc User s manual Calibration report documenting traceability to the United States National Institute of Standards and Technology NIST molbox FLOW TERMINALS molboxt OPTIONS Description molbox1 Option 009 MFC control option Part Number 03 Purpose Set and read analog voltage and current MFCs Optional board is built in to molbox1 and connector is on rear panel Delivered with MFC cable and connection kit Description molbox1 Option 012 drivers option Part Number 04 Purpose Provide 8 on off 12 VDC signals to drive external valves or other accessories Rear panel connector supplied OPTIONAL ACCESSORIES Rack mount kit molbox1 P N 401154 Standard 19 in rack mount kit for molbox1 Panel is 5 25 in 3U high MFC Switchbox Supply power to 5 MFCs simultaneously and switch molbox1 MFC control option between five channels See MFC Switchbox brochure molstics Gas handling hardware and mounting system for molblocs See molstic brochure COMPASS for molbox PC based calibration software to automate calibrations with molbloc molbox See COM
30. ranges with different gases and pressure requirements SPECIFICATIONS Pages 17 and 18 list complete molbloc molbox technical specifications Though you ll find this catalog goes well beyond traditional commercial literature in its efforts to inform you everything about molbloc molbox and how it can benefit your flow measurements cannot be included here For additional molbloc molbox assistance or information on DHI s other flow and pressure calibration products and services please contact DHI or your local representative You can count on our commitment to objectively analyze your needs and recommend the best solutions to meet them TM molbloc Laminar Flow Element BOLERU AN Piston GN Body om where PeM Prez Zen ReT rete P M See p 16 for T NPT List of Symbols i P P2 Pen NET Known from P2 Come af e wT Determined trom Gravimetric Calibration Cg INTRODUCTION melblo e molbeo M General Features FOUNDED ON PROVEN LAWS OF GAS BEHAVIOR The molbloc molbox flow measurement principle follows established laminar flow theory In accordance with well known laws of gas behavior the flow of a known gas in the laminar flow regime can be calculated from the flow path geometry and the gas pressure and temperature see molbloc flow equation on previous page V P N A Parabolic Gas Velocity Distribution
31. rease confidence and guarantee homogeneity of measurements flow intercomparisons are regularly performed with a variety of primary methods in other mass flow metrology laboratories The DHI calibration system is used to calibrate every molbloc and each one is delivered with a complete calibration report documenting traceability to the United States National Institute of Standards and Technology NIST and including specific measurement results r 7 ihin perese nn aS gt Tae ge Gravimetric Calibration RECALIBRATION OPTIONS The recommended recalibration interval for a molbloc molbox system is one year The one year interval is not a reflection of the intrinsic stability of the system which without incident should hold its specifications much longer One year is recommended as a precaution considering variations in conditions of use from application to application and the central role that molbloc molbox usually plays in the user s flow measurement system After the first two annual recalibrations an analysis of the results may justify extending recalibration interval There are two aspects to recalibrating a molbloc molbox system One is the calibration of the pressure transducers in the molbox the other is the verification of the stability of the laminar flow path of the molbloc These can be conducted independently one from the other GENERAL FEATURES Calibration of the molbox pressure transducer
32. s is a routine procedure for any facility with high accuracy pressure calibration capability in the range of atmosphere to 550 kPa absolute 80 psia Transducer readings can be adjusted to agree with a calibration standard by setting simple calibration coefficients in the molbox Note The molbox RFM microrange option pressure transducer requires a O to 10 kPa 1 5 psi gauge calibration Calibration of the molblocs requires a flow standard with lower measurement uncertainty than that of the molbloc molbox system In the original factory calibration proprietary calibration coefficients which characterize the molbloc flow path are determined Since molblocs are static mechanical elements in which there is no inherent drift the original factory coefficients do not change unless the molbloc is damaged or contaminated For this reason molblocs that are found out of tolerance in recalibration are generally considered to need repair and are returned to DHI for service Special calibration software is available for facilities that require the capability to adjust molbloc readings to agree with their standards COMPASS FOR molbox CALIBRATION ASSISTANCE SOFTWARE COMPASS for molbox calibration assistance software takes molbloc molbox to the next step in automating calibrations COMPASS for molbox and a personal computer work with molbloc molbox to create a modern full function turnkey system for calibrating and testing flow devices COMP
33. straight through a simple shape minimizing opportunities for contaminants to collect All wetted surfaces are electropolished to a 0 15 u Ra finish to avoid particle collection from the flowing gas Every molbox has identical upstream and downstream pressure transducers In molbox1 these provide stability of 0 01 per year Each time the pressure transducers are zeroed differentially they are also compared one to the other and the user is alerted to disagreements that may indicate excessive drift The platinum resistance thermometers PRTs that measure molbloc temperature are read by the molbox s ohmic measurement system At each molbox power up an automated routine calibrates the ohmic measurement system against on board reference resistors with three year stability of 0 005 This combination provides temperature reading stability of better than 0 01 per year Asa precaution against damage or malfunction the temperature readings of the two PRTs are also regularly compared to each other to identify excessive disagreements OUTSTANDING RANGEABILITY molbloc molbox s very high rangeability makes it particularly effective when configuring a system to cover a wide range of devices to be calibrated molbloc molbox s flow measurement uncertainty is relative to the flow reading not the molbloc full scale Since the typical device to be calibrated has measurement uncertainty that is relative to its full scale one range of molb
34. ta acquisition and processing functions necessary to determine the flow through a molbloc flow element that is connected to it molbloc flow elements of varying flow path size To configure a molbloc molbox for your specific requirements follow the steps below 1 Select molbox or molbox RFM see pp 10 to 12 Choose molbox1 to e Minimize measurement uncertainty molbox1 uses premium pressure transducers to provide the lowest measurement uncertainty and best stability over time Set and read analog mass flow controllers MFCs with the molbox molbox1 offers an integrated analog MFC control option which sets and reads 0 to 5 V and 4 to 20 mA MFCs e Support two molbloc channels Choose molbox RFM to e Reduce system cost e Minimize molbox size e Minimize the number of molblocs needed to cover your range with the microrange option If you do not need the molbox to set and read analog MFCs 2 Select the molbloc Mass Flow Elements see pp 13 to 16 This includes selecting the molbloc pressure dependent calibration type s sizes and special gas Calibrations if needed a Select one of the three pressure dependent calibration types see p 14 Determine the pressure at which the molbloc must be operated depending on whether it will be upstream or downstream of the device under test PUTTING TOGETHER A SYSTEM are available to cover different flow ranges molstic mounting systems are offered as an
35. to 48 psia 50 kPa 7 5 psi Single P Any specified high pressure single molbloc non N2 gases only upstream pressure between 325 and 525 kPa absolute 48 to 76 psia 50 kPa 7 5 psi Operating pressure values are absolute For approximate gauge pressure values subtract typical atmospheric pressure SPECIAL GAS CALIBRATIONS Standard molblocs include a Nitrogen N full mod low pressure calibration A different N calibration and or calibration with gases other than N must be ordered as separate line items The DHI mass flow calibration facility does not support calibration of all gases for all ranges Please verify availability before ordering DESIGNATION DESCRIPTION PART NO Special N2 Calibration Full Mod Hi P 600204 Special N2 Calibration Downstream gt 5E1 molbloc 600206 Special N2 Calibration Downstream 1E1 5El molbloc 600205 special Gas Calibration Full Mod Lo P 1E1 5E1 molbloc 600202 specify gas special Gas Calibration Full Mod Lo P gt 5E1 molbloc 600201 specify gas Special Gas Calibration Full Mod Hi P 1E1 5E1 molbloc 600207 specify gas Special Gas Calibration Full Mod Hi P gt 5E1 molbloc 600208 specify gas Special Gas Calibration Downstream 1E1 5E1 molbloc 600209 specify gas Special Gas Calibration Downstream gt 5E1 molbloc 600210 specify gas Special Gas Calibration Single P 1E1 5E1 molbloc specify 600211 gas and single pressure value betwe
36. ure readings provides the Embedded Pressure a PRT Tap gt pS T P1 Pa r N J Gas Entering molbloc Gas at molbloc cae Temperature sss SAN SAK molbloc Gas Pressure and Temperature Measurement differential pressure across the molbloc Internal molbox valving and an automated tare function allow the two transducers differential measurement to be autozeroed at any time independently of current flow conditions A patented design greatly improves the determination of the temperature of the gas flowing through the molbloc flow element Rather than attempting to measure the temperature of the gas entering or exiting the flow element with a probe the gas is forced to the temperature of the molbloc body and the molbloc body temperature is measured The large thermal mass of the molbloc body and the very large metal to gas contact surface created by molbloc s annular flow path cause the gas to take on the molbloc s temperature An isothermal gas expansion occurs as gas flows through the molbloc The temperature of the isotherm is determined by measuring the molbloc body temperature The molbloc body temperature is measured very precisely using two platinum resistance thermometers PRT embedded symmetrically in the molbloc body The PRTs are read by an ohmic measurement system in the molbox that self calibrates with on board reference resistors T
37. vice under test DUT gas conversion factor if applicable GAS Function Select the gas being flowed more than 18 gases supported UNIT Function Select the mass flow unit of measure with adjustable reference temperature for volumetrically based mass flow units and adjustable pressure and temperature for volume flow units Displays Function Select special advanced function displays including Average Rate Hi Lo Totalize Second Flow Unit Deviation Freeze Clean Resolution Function Adjust the resolution of the measured flow display molbloc Function View current molbloc identification initialize a newly connected molbloc Pressure amp Temperature Function Display real time molbloc pressure and temperature measurements and the Reynolds number of the current flow Valving Functions Access automated pressure tare leak checking and gas purging functions molbox FLOW TERMINALS 10 11 eer Calis a tales F gonn J ra n O i WIERA Ber molbox1 features include Flow measurement uncertainty of 0 2 of reading Very high performance quartz crystal oscillator based pressure transducers Two molbloc channels allowing two molblocs to be connected simultaneously and measurements to be switched between them using the A_B function Also supports A B and A B measurement Integrated analog MFC measurement and control option with switchbox for multiple channels Valve driver o
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