0240 PTV Inlet
Contents
1. Leak testing the PTV module only appropriate connector on the EPC board Reconnect the gas supply and turn on the main power switch Set the pressure to 25 psi and the flow to 60 mL min 7 Lay the EPC module on the lab bench and use an electronic leak detector to locate the leaky component on the module Figure 240 26 Leak testing the EPC module on the lab bench 8 Ifthe leaky component is serviceable such as a vent inlet fitting see diagram of serviceable parts Figure 240 27 replace it Otherwise replace the EPC module 44 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatograph Service Manual Programmed Temperature Vaporization Inlet PTV 240 Leak testing the PTV module only Figure 240 27 EPC module serviceable parts Correcting leaks 1 Useanelectronic leak detector to check all areas of the inlet and plumbing that are potential sources of a leak 2 Tighten loose connections to correct leaks if necessary You may need to repeat the leak test 3 Ifthe pressure drop is now 0 5 psi or less you can consider the inlet system leak free If the pressure drops faster than the acceptable rate continue to search for leaks and repeat the pressure test Potential leak points Check the following areas when checking an inlet system for leaks In the oven Make sure the bottom of the inlet is correctly capped Jun 2001 Inlets 45 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Te2. Be careful not to excessively bend the 1 16 inch lines For best results lift the head to clear the inlet and then push it to either side to allow access 5 To reinstall the septum head gently align the head with the inlet and manually engage the free spinning nut to the inlet The nut should thread easily onto the inlet If resistance is felt unscrew the nut and retry Excessive force can irreparably damage the inlet 6 Tighten the retaining nut 1 2 turn past finger tight 7 Ifthe carrier gas and septum purge lines were removed reinstall them 34 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatograph Service Manual Programmed Temperature Vaporization Inlet PTV 240 Replacement procedures 8 Check all connections for leaks If necessary the retaining nut can be tightened an additional 1 4 turn to eliminate leaks Replacing the septum Either a regular septum or a Merlin microseal can be used with the septum head If the inlet temperature is set below 40 C the Merlin microseal may not seal effectively For inlet temperatures below 40 C use a regular septum for the inlet seal 1 To replace the septum cool the inlet to ambient temperature 2 Unscrew counterclockwise the septum cap or Merlin cap 3 Remove the septum or Merlin microseal taking care not to scratch the interior of the septum head 4 Install a new septum or Merlin microseal and the correct cap When installing a Merlin microseal note that
3. Temperature conversion To detector Figure 240 3 Splitless mode flow control diagram sample injection After the injection the solenoid valve opens and the flow control is the same as during split mode operation See Figure 240 1 or Figure 240 2 Jun 2001 Inlets 7 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV Splitless modes Pulsed splitless mode The pressure pulse modes using the septum or septumless head increase inlet pressure just before the beginning of a run and return it to the normal value after a specified amount of time The pressure pulse sweeps the sample out of the inlet and into the column faster reducing the chance for sample decomposition in the inlet 8 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatograph Service Manual Programmed Temperature Vaporization Inlet PTV 240 Solvent vent mode Solvent vent mode Stage 1 Sample and vent In solvent vent mode the sample is injected into a cold inlet During sampling and for the duration of the venting the solenoid valve is open The solvent vaporizes and is swept out the vent while the sample deposits on the liner walls or packing If conditions are properly chosen and the sample is suitable analytes deposit in the inlet liner while the solvent evaporates and is swept out Large or multiple injections can be used to concentrate sample in the inlet before transferring it to
4. 7 Remove the heater connector from the side panel and remove the cryo connector from the thermocouple conversion board at the back of the GC Remove connectors Disconnect cable Figure 240 12 PTV electrical connections 8 Replace the PTV inlet assembly and reassemble in reverse order To attach the cryo line to the new inlet assembly tighten the nut finger tight then 14 turn more using two open end wrenches 9 Check the system for leaks Replacing the CO or LN inlet cryo assembly 1 Once the PTV with cooling assembly is removed the cryo assembly on the inlet can be replaced 2 Remove the PTV inlet as described under Replacing the PTV with cooling assembly 3 Remove the three screws on the cryo assembly from the PTV inlet and remove the cryo assembly 18 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatograph Service Manual Programmed Temperature Vaporization Inlet PTV 240 Replacement procedures PTV inlet PTV inlet with cooling assembly Inlet cryo assembly Remove screws Figure 240 13 Removing the inlet cryo assembly 4 Install the new cryo assembly over the inlet body Be sure to align the assembly so that the fitting is closest to the wires as shown in Figure 240 12 5 Reassemble in reverse order 6 Check for leaks Replacing the PTV manifold assembly The PTV manifold assembly is available as a replacement part with or without the connected plu
5. cleanup The solenoid valve opens again and the system returns to the Stage 1 configuration but with different setpoints The PTV inlet is flushed through the split vent Split SPR vent vent Septum holder Pv2 Valve open To detector Figure 240 6 Solvent vent mode flow control diagram purge and cleanup 12 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatograph Service Manual Programmed Temperature Vaporization Inlet PTV 240 Replacement procedures Replacement procedures In addition to the PTV consumables inlet adapters columns Teflon ferrules and septa the replacement parts in the PTV inlet assembly are The entire PTV inlet pneumatics and manifold assembly The PTV manifold assembly PTV gang weldment and front trap assemblies The filter The head assembly septum or septumless The cryo shroud on the inlet body CO or liquid nitrogen The PTV thermocouple PCB The O rings and restrictors in the gang fitting assembly Replacing the PTV inlet pneumatics and manifold The entire PTV assembly can be easily replaced 1 Turn off the oven and the inlet and allow them to cool WARNING Turn off the oven and the inlet and allow them to cool Turn off all flows at the initial gas supply Then turn off the main power switch and unplug the power cord 2 3 Remove the top cover the inlet fan cover the inlet cover the left side panel the top rear panel the pneumatics cha
6. number 200 mm 31 1 5182 9754 250 mm 45 1 5182 9761 320 mm 45 1 5182 9761 530 mm 70 1 5182 9762 1 Unscrew the column nut from the adapter Remove the nut and the column from the inlet 2 Witha6mm wrench remove the inlet adapter being careful not to lose the silver seal inside Save the adapter for later use 3 Select the appropriate inlet adapter for the column to be installed Insert a new silver seal part no 5182 9763 package of five into the adapter and screw the adapter onto the inlet fingertight Tighten the adapter an additional 1 16 to 1 8 turn Be careful not to overtighten the adapter The inlet can be damaged if the adapter is forced If the adapter leaks check the silver seal and replace it if necessary Jun 2001 Inlets 27 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV Replacement procedures Installing the column Graphpack 2M ferrules are sized to the column outer diameter Column Graphpack ferrule Quantity Part no ID hole ID 200 mm 0 31 mm 10 5182 9756 250 mm 0 40 mm 10 5182 9768 320 mm 0 45 mm 10 5182 9769 530 mm 0 70 mm 10 5182 9770 1 Place the appropriate Graphpack ferrule onto the column inlet end and pull it at least 30 mm from the end 2 With a glass knife or other fused silica cutter remove approximately 10 mm from the column end to eliminate graphite contamination 3 Position the ferrule so t
7. the column for analysis Figure 240 4 shows the inlet flow control with the septum head installed In the septumless head the flows are the same as in the septum head except the septum purge vent is bypassed directly to the carrier flow through the Jun 2001 inlets 9 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV Solvent vent mode gang fitting on the flow manifold Flow control is the same as for the septum head Split SPR vent vent Total flow holder t control loop PV2 Valve l l l Septum l l I open Temperature conversion To detector Figure 240 4 Solvent vent mode flow control diagram sample and vent 10 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatograph Service Manual Programmed Temperature Vaporization Inlet PTV 240 Solvent vent mode Stage 2 Sample transfer When solvent venting ends the solenoid valve closes and the inlet heats to the final temperature The sample transfers onto the capillary column Split SPR vent vent Column head pressure control loop Seni eptum Flow holder limiting PV2 Solenoid valve closed To detector Figure 240 5 Solvent vent mode flow control diagram sample transfer Jun 2001 Inlets 11 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV Solvent vent mode Stage 3 Purge and
8. 0 Replacement procedures 8 Insert the liner into the inlet from above until the unpacked side of the ferrule rests on the top of the inlet 9 Replace the sampling head and reconnect the lines if necessary 10 Check all connections for leaks If necessary tighten them again by hand Jun 2001 inlets 37 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV Diagnostics Diagnostics Cryo timeout When a run does not start within a specified time after the oven equilibrates cryo timeout occurs and the inlet temperature shuts down Cryo fault Shuts down the inlet temperature if it does not reach setpoint in 16 minutes of continuous cryo operation Note that this is the time to reach the setpoint not the time to stabilize and become ready at the setpoint Shutdown behavior Both Cryo timeout and Cryo fault can cause cryo shutdown If this happens the inlet heater is turned off and the cryo valve closes The GC beeps and displays this message SHUTDOWN 18 Front inlet cryo shutdown The inlet heater is monitored to avoid overheating If the heater remains on at full power for more than 2 minutes the heater is shut down The GC beeps and displays this message SHUTDOWN 22 Front inlet heating too slowly To recover from either condition turn the GC off then on or enter a new setpoint 38 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatogr
9. 240 Programmed Temperature Vaporization Inlet PTV Theory of operation The Programmed Temperature Vaporization PTV Inlet collects each portion of an injected sample inside a 120 microliter liner until the entire quantity of sample is obtained During the hold the sample is held at a programmable temperature as low as 60 C using CO cooling or as low as 160 C using liquid nitrogen When the complete sample is collected the PTV heats and delivers the sample onto the column The PTV can be used with either a septum or septumless head operating in either split splitless or solvent vent modes In the solvent vent mode analytes are thermally trapped in the liner while the solvent is removed With the solvent gone the liner volume can be used for another injection Injection can be repeated several times to concentrate the analytes from a large sample volume After injection and solvent removal the analytes are transferred to the column This can replace the need for offline reconcentrating and minimize loss of sample Operating modes The Agilent Programmed Temperature Vaporization PTV Inlet System has five operating modes e The split mode is generally used for major component analyses e The pulsed split mode is like the split mode but applies a pressure pulse to the inlet during sample introduction to speed the transfer of material onto the column e The splitless mode is used for trace analyses The pulsed s
10. Jun 2001 inlets 21 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV Replacement procedures Filter and O rings 2 not shown PTV front trap assembly Filter and O rings 2 not shown PTV SMLS gang weldment PTV front trap assembly Figure 240 15 PTV plumbing assemlies Removing both the manifold and plumbing assemblies 1 Loosen the three captive Torx screws which secure the inlet to the oven and lift the PTV inlet out of the oven 2 Disconnect the carrier gas supply line split vent line and septum purge line for the septum head from the inlet Straighten the tubing at the manifold so that the manifold can be easily removed from the chassis 22 of 46 Inlets Agilent 6890 Gas Chromatograph Service Manual Jun 2001 Programmed Temperature Vaporization Inlet PTV 240 Replacement procedures 5 Lift the filter trap from the LCO2 bracket and then slide the manifold assembly out of the chassis Replace the manifold assembly and plumbing and reassemble in reverse order Check the system for leaks Removing the PTV manifold only 1 2 3 4 5 Remove the plumbing block from the front of the manifold by removing the screws Inspect the O rings in the block for damage and replace if necessary Slide the manifold from the chassis and replace Installation is the reverse of removal Check the
11. aph Service Manual Programmed Temperature Vaporization Inlet PTV 240 Leak testing Leak testing Preparation 1 Cool the column to ambient and cool inlets to below 75 C to avoid damage to deactivated glass liners 2 Remove the column from the inlet fitting on the inside of the oven 3 Ifaseptum head is installed and the quality of the septum or microseal and Graphpack 3D ferrule on the glass liner are unknown replace them now 4 Cap the inlet s column fitting and the septum purge vent septum head only Use solid no hole Vespel type ferrules 1 8 inch part no 0100 1372 and 1 16 inch part no 5181 7458 with a 1 8 inch Swagelok nut part no 5180 4103 and a capillary column nut Note As alternate capping devices a 1 8 inch Swagelok cap can be used for the septum purge vent A capillary column nut with a solid piece of wire the size of a paper clip and a 0 5 mm ID graphite ferrule may be used for the inlet column fitting Jun 2001 Inlets 39 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV Leak testing Figure 240 25 Capping the bottom of the inlet and septum purge vent Note Make sure that the carrier gas source pressure is at least 35 psi Carrier source pressure should always be at least 10 psi greater than the desired inlet pressure Performing the leak test Note Be sure to complete all of the preparation steps on page 39 bef
12. bed in Replacing the PTV manifold assembly Jun 2001 Inlets 25 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV Replacement procedures 3 Once the PTV manifold is removed remove the two mounting screws that secure the thermocouple conversion board onto the pneumatics board and remove the board PTV manifold assembly PTV thermocouple PCB Remove 2 screws Figure 240 17 Replacing the PTV thermocouple PCB 4 Replace the board and reassemble in reverse order 5 Check the system for leaks Replacing the filter 1 Turn off the GC oven and the inlet and allow them to cool 2 Set all GC flows to zero 3 Remove the pneumatics cover 26 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatograph Service Manual Programmed Temperature Vaporization Inlet PTV 240 Replacement procedures 5 6 Lift the filter trap from the mounting bracket and unscrew the filter trap assembly Remove the old filter and O rings and replace them Reassemble the trap Replacing the inlet adapter The Graphpack 2M connector the inlet adapter at the bottom of the inlet is sized to the column diameter When installing a different diameter column change the adapter The adapter number is stamped on the side of the adapters Select the smallest hole diameter that will accept the column Column Inlet adapter Quantity Part no ID
13. e and the flow sensor The solenoid valve is open and proportional valve 2 acts as a back pressure regulator controlled by the pressure sensor on the septum purge vent line Split SPR vent vent Septum mie Total flow holder i iting control loop j frit Flow Temperature conversion To detector Figure 240 1 Split mode flow control diagram septum head installed Jun 2001 Inlets 3 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV Split modes The temperature of the liner can be held below or above the boiling point of the carrier solvent Septumless head installed In the septumless head the flows are the same as in the septum head except the septum purge vent is bypassed directly to the carrier flow through the gang fitting on the flow manifold Flow control is the same as for the septum head See Figure 240 2 Split SPR vent vent Septumless head PV2 Valve open Temperature conversion To detector Figure 240 2 Split mode flow control diagram septumless head installed 4 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatograph Service Manual Programmed Temperature Vaporization Inlet PTV 240 Split modes Pulsed split modes The pressure pulse modes using the septum or septumless head increase inlet pressure just before the beginning of a run and return it to the normal value after a speci
14. f necessary 8 Ifreplacing the PTV gang weldment install new O rings in the manifold plumbing block 24 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatograph Service Manual Programmed Temperature Vaporization Inlet PTV 240 Replacement procedures WARNING Caution WARNING 9 Replace the gang weldment or front trap assembly and reassemble in reverse order 10 Check the system for leaks Replacing a gang fitting restrictor or O ring 1 Turn off the oven and the inlet and allow them to cool Turn off the oven and the inlet and allow them to cool Turn off all flows at the initial gas supply Then turn off the main power switch and unplug the power cord 2 Remove the top cover the inlet fan cover the inlet cover and the pneumatics chassis cover 3 Remove the screw in the gang fitting Gently tap the fitting to remove the restrictor for cleaning replacement Inspect the O rings and replace if necessary 4 Reassemble in reverse order Check the plumbing for leaks Replacing the PTV thermocouple PCB Follow ESD precautions when performing this procedure Turn off the oven and the inlet and allow them to cool Turn off all flows at the initial gas supply Then turn off the main power switch and unplug the power cord 1 Remove the top cover the inlet fan cover the inlet cover the left side panel the top rear panel the RFI cover and the pneumatics chassis cover 2 Remove the PTV manifold as descri
15. fied time The pulse sweeps the sample out of the inlet and into the column faster reducing the chance for sample decomposition in the inlet Jun 2001 Inlets 5 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV Splitless modes Splitless modes In splitless mode with or without a pressure pulse the solenoid valve is closed during injection and vaporization of the sample and while the sample transfers to the column At a specified time after injection the valve opens to sweep vapors left in the liner out the split vent to prevent solvent tailing due to the large inlet volume and small column flow rate Figure 240 3 shows the inlet flow control during injection and sample transfer with the septum head installed The flow sensor measures the flow rate but the pressure sensor on the septum purge line controls the column head pressure using proportional valve 1 In the septumless head the flows are the same as in the septum head except the septum purge vent is bypassed directly to the carrier flow through the 6 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatograph Service Manual Programmed Temperature Vaporization Inlet PTV 240 Splitless modes gang fitting on the flow manifold Flow control is the same as for the septum head Split SPR vent vent j Column head l pressure control loop l Septum Flow holder limiting a pv2 ave frit closed
16. h the Time and the Front Inlet Back Inlet keys e If there is less than 0 5 psi pressure loss consider the system leak tight e Ifpressure loss is much greater than 0 5 psi there is a leak that must be found and corrected Note however that you may want to slightly decrease the leak test time based on the internal inlet volume which changes with the liner type used smaller volumes shorter acceptable leak test times See Correcting leaks later in this section When the system is considered leak tight the caps may be removed the column reinstalled its dimensions configured at keyboard and the desired pressure and flow rate set Jun 2001 Inlets 41 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV Leak testing the PTV module only Leak testing the PTV module only Occasionally to locate small leaks you will need to isolate the EPC module from the inlet weldment and leak test the EPC module separately 1 On the keyboard turn off pressure to the inlet being tested Press Front Inlet or Back Inlet scroll to the Pressure field and press Off Use a Torx T 10 screwdriver to remove the screw in the plumbing block on the front of the module Remove the plumbing block from the EPC module being careful not to lose the O rings between the block and the module Replace the inlet s plumbing block with the leak test block part no G1530 20660 fro
17. hat itis 17 mm from the column end Place a small mark typewriter correction fluid is useful at the back of the ferrule and making sure that the column is correctly positioned insert the column end into the adapter 28 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatograph Service Manual Programmed Temperature Vaporization Inlet PTV 240 Replacement procedures 2 17mm O Mark column here Figure 240 18 Column installation 4 Screw the column nut on fingertight Use a wrench to tighten the column nut 1 8 to 1 4 turn Be careful not to overtighten Removing the septumless head 1 2 3 Cool the inlet to room temperature Disconnect the carrier gas line Unscrew the septumless head counterclockwise from the inlet Screw the new head onto the inlet Tighten it 1 8 turn past finger tight Jun 2001 Inlets 29 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV Replacement procedures Figure 240 19 Removing the carrier gas line 5 Reconnect the carrier gas line 6 Checkallconnections on the sampling head for leaks If necessary tighten them again by hand Cleaning the septumless head Minor deposits from sample mixtures can collect in the head Dust and abraded material particles can enter together with the syringe needle eventually causing leaks 1 Disconnect the carrier gas line and unscrew the head from the inlet 2 Unscrew t
18. he sealing element from the head Carefully remove the Viton seal and the pressure spring Do not use a sharp object to extract the valve body this can leave scratches that cause leaks 30 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatograph Service Manual Programmed Temperature Vaporization Inlet PTV 240 Replacement procedures Figure 240 20 Disassembling the septumless head 3 Unscrew the guide cap from the head and remove the Teflon ferrule 4 Carefully insert a syringe with a 23 gauge needle into the head to press the valve body with the Kalrez seal slightly out of the head Carefully tap the head on a soft smooth surface so that the valve body falls out completely or slips out far enough to grasp it with your fingers 5 Remove the seal from the valve body 6 Carefully clean all components in hexane 7 Inspect the Teflon ferrule seals and valve body for damage and replace if necessary 8 Assemble the head in reverse order Make sure that you work absolutely lint free and that the seals and the pressure spring are not damaged Jun 2001 Inlets 31 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV Replacement procedures 9 Check the entire system again for leaks if necessary carefully retighten the guide cap with the syringe needle inserted slightly more and or replace the Kalrez seal If the head leaks when a syringe is inserted the Tefl
19. hown in Figure 240 10 is generally the lowest level replacement part Figure 240 10 PTV with cooling assembly 1 Turn off the inlet and allow the inlet to cool 16 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatograph Service Manual Programmed Temperature Vaporization Inlet PTV 240 Replacement procedures WARNING Turn off the oven and the interface and allow them to cool Turn off all flows at the initial gas supply Then turn off the main power switch and unplug the power cord 2 Remove the top cover the inlet fan cover the inlet cover the left side panel the top rear panel the pneumatics chassis cover 3 Remove the column 4 Loosen the three captive Torx screws which secure the inlet to the oven and lift the PTV inlet out of the oven Caution When removing attaching the inlet cryo line use one wrench to support the cryo line fitting on the inlet body and one to tighten the nut Failure to do this could break the fitting on the inlet Remove gas lines Figure 240 11 Removing the gas lines from the inlet 5 Disconnect the carrier gas line to the inlet at the inlet Remove the split vent gas line and the septum purge line as applicable Using two wrenches remove the cryo fitting from the inlet Jun 2001 inlets 17 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV Replacement procedures 6 Remove unscrew the head from the inlet
20. m the leak test kit part no G1530 60960 Make sure you install O rings if needed between the block and the EPC module to create a seal The leak test block is a special fitting that plumbs the carrier gas coming out of the module directly back into the septum purge and split vent flow paths on the module It allows the carrier gas septum purge and split vent line to function normally as if an inlet were present Perform the normal leak test for the EPC inlet as described previously in this section With the inlet removed the internal volume is quite small and a pressure loss of 0 5 psi or less in 5 minutes time is considered to be leak free If there is a leak you will probably need to remove the flow manifold to try to isolate the leak as described in the following Locating leaks on the flow manifold procedure If there is an increase in pressure see the following Forward pressure valve leaks procedure 42 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatograph Service Manual Programmed Temperature Vaporization Inlet PTV 240 Leak testing the PTV module only Forward pressure valve leaks Occasionally an increase in pressure rather than a decrease may be observed This is usually due to slight leakage into the module across the forward pressure control proportional valve Although slight leaks of this nature do not create chromatographic problems they may obscure other small leaks that do cause problems by allowing ai
21. mbing When replacing just the manifold the plumbing is removed at the manifold outlet block When replacing the plumbing and manifold the plumbing is disconnected from the inlet Jun 2001 Inlets 19 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV Replacement procedures Note When installing a new PTV manifold assembly and plumbing it is not necessary or recommended to disconnect the plumbing from the module The system is leak tested at the factory Caution Follow ESD precautions when performing this procedure 1 Turn off the oven and the inlet and allow them to cool WARNING Turn off the oven and the inlet and allow them to cool Turn off all flows at the initial gas supply Then turn off the main power switch and unplug the power cord 2 Remove the top cover the inlet fan cover the inlet cover the left side panel the top rear panel the pneumatics chassis cover and the RFI cover 3 Remove the column 4 Remove the mounting screw in the top of the PTV manifold 20 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatograph Service Manual Programmed Temperature Vaporization Inlet PTV 240 Replacement procedures Figure 240 14 Removing the manifold mounting screw 5 Disconnect the manifold ribbon cable from the pneumatics PCB Disconnect the cryo cable power cable and thermocouple cable connectors from the PTV thermocouple PCB on the manifold
22. mperature Vaporization Inlet PTV Leak testing the PTV module only On the inlet e Septum septum head only e Lower inlet seal at bottom of inlet e Ferrule on inlet liner e Connections for carrier gas septum purge septum head only At EPC module e O rings behind the block where the inlet s pneumatic lines enter the module e Two O rings for each valve e Septum purge cap septum head only e Chemical trap O rings e O rings in gang fitting 46 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatograph Service Manual
23. on ferrule is the problem If the head leaks without a syringe inserted the seals may need to be replaced Replacing the Teflon ferrule 1 Unscrew the guide cap from the septumless head and remove the Teflon ferrule Figure 240 21 Installing a Teflon ferrule 32 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatograph Service Manual Programmed Temperature Vaporization Inlet PTV 240 Replacement procedures 5 6 Push the guide cap and the new Teflon ferrule over the syringe needle so that at least 10 mm of the needle tip is exposed Guide the end of the syringe needle into the septumless head until the ferrule meets the septumless head Tighten the guide cap until resistance is first felt Check for leaks when the syringe needle has been fully introduced If necessary carefully tighten the guide cap until the inlet stops leaking Removing replacing the septum head The septum head connects to the inlet via a free spinning retaining nut 1 2 Turn off the inlet heater and allow it cool If replacing the septum head disconnect the split vent and septum purge lines Use a 5 8 inch wrench to loosen the retaining nut on the septum head Jun 2001 Inlets 33 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV Replacement procedures Figure 240 22 Removing the septum head 4 Gently remove the septum head assembly from the inlet
24. ore continuing 1 Set the inlet to Split Mode 2 Configure the column as 0 length Press Config Column 1 or Config Column 2 and enter 0 in the first column of the Dim field 3 Set the inlet s Total Flow to 60 mL min Press Front Inlet or Back Inlet and enter 60 in the Tot flow field 40 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatograph Service Manual Programmed Temperature Vaporization Inlet PTV 240 Leak testing Note Set the pressure to 25 psi Scroll to Pressure and enter 25 in the Pressure field Wait approximately 15 seconds for equilibration If pressure cannot be achieved either a very large leak is present in the system or the supply pressure is not high enough Turn the inlet pressure Off Press Front Inlet or Back Inlet scroll to the Pressure field and press Off Both the flow controller and the back pressure valves will close When the inlet pressure or flow is turned off the safety shutdown feature including the audible alarm is not functional The inlet will not automatically shut down This will provide you with unlimited time to locate leaks T Note the Actual reading on the display and monitor the pressure for 10 minutes You can use the stopwatch feature of the 6890 GC to monitor the time Press Time and then Enter to start timing then toggle between the time and the pressure reading wit
25. plitless mode provides a pressure pulse during sample introduction e The solvent vent mode collects analyte in the liner while venting solvent and is used for large volume injection Either single or multiple injections can be made for each run Jun 2001 Inlets 1 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV Theory of operation Sampling heads The septum head uses either a regular septum or a Merlin microseal to seal the syringe passage A stream of gas sweeps the inner side of the septum and exits through the septum purge vent on the pneumatics module It may be used with either automatic or manual injection The septumless head uses a check valve instead of a septum to seal the syringe entrance passage It may be used with either automatic or manual injection 2 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatograph Service Manual Programmed Temperature Vaporization Inlet PTV 240 Split modes Split modes Septum head installed In the two split modes with or without a pressure pulse the solenoid valve is open and divides the gas stream entering the inlet between the column flow the split vent flow through the solenoid valve and the septum purge flow The ratio of the split vent flow to the column flow is called the split ratio Figure 240 1 shows the inlet flow control Overall carrier and sample gas flow is controlled by the first proportional valv
26. r into the system The valves can leak at about 0 2 mL min and be within specification To check for internal valve leakage when leak testing the EPC module only 1 Remove the supply pressure at the carrier inlet fitting and quickly cap the fitting with a solid 1 8 inch Vespel plug and a Swagelok nut 2 Check the actual pressure on the display and monitor it for 5 minutes Pressure loss should not be greater than 0 5 psi Locating leaks on the flow manifold If the EPC module appears to have a leak you can remove it to locate the leaky component The leak test kit part no G1530 60960 contains a longer ribbon cable to allow you to lay the EPC module on the benchtop for testing Caution Be sure to wear an ESD strap grounded to the 6890 GC chassis while performing this procedure 1 Turn off the main power switch 2 Remove the top plastic pneumatics cover and the detector cover 3 Remove the top rear cover on the GC 4 Disconnect the ribbon cable for the module from the main EPC board You may have to remove the adjacent ribbon cable also 5 Use a Torx T 20 screwdriver to remove the screw from the top of the module and slide the module out of the back of the GC 6 Connect one end of the leak test ribbon cable G1530 61370 to the ribbon cable connector on the EPC module and connect the other end to the Jun 2001 Inlets 43 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV
27. ssis cover and the RFI cover Remove the top mounting screw in the PTV manifold assembly Jun 2001 Inlets 13 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV Replacement procedures Figure 240 7 Removing the PTV manifold assembly 4 Remove the column 5 Loosen the three captive Torx screws which secure the inlet to the oven and lift the PTV inlet out of the oven 14 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatograph Service Manual Programmed Temperature Vaporization Inlet PTV 240 Replacement procedures Loosen screws Figure 240 8 Removing the PTV inlet 6 Remove the heater connector from the side panel Remove connector Figure 240 9 PTV electrical connectors Jun 2001 inlets 15 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV Replacement procedures 7 Disconnect the power cable thermocouple connector and cryo connector from the flow module and board Disconnect the module ribbon cable from the pneumatics board 8 Slide the flow module out of the chassis remove the chemical trap assembly from the mounting bracket and remove the PTV assembly from the GC 9 Removing the entire PTV assembly 10 Replace the PTV assembly and flow module and re assemble in reverse order Replacing the PTV with cooling assembly The PTV with cooling assembly s
28. system for leaks Replacing the plumbing assemblies 1 Turn off the oven and the inlet and allow them to cool WARNING Turn off the oven and the inlet and allow them to cool Turn off all flows at the initial gas supply Then turn off the main power switch and unplug the power cord 2 Remove the top cover the inlet fan cover the inlet cover the top rear panel and the pneumatics chassis cover 3 Remove the column 4 Loosen the three captive Torx screws which secure the inlet to the oven and lift the PTV inlet out of the oven 5 To replace the PTV gang weldment disconnect the plumbing block from the PTV manifold assembly Then disconnect the carrier gas line and the septum purge line septum head only from the inlet Unscrew the filter trap assembly and remove the PTV gang weldment assembly Jun 2001 Inlets 23 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV Replacement procedures 6 To replace the PTV front trap assembly disconnect the split vent line from the inlet Unscrew the filter assembly and remove the PTV front trap assembly Filter and O rings 2 not shown PTV front trap assembly Filter and O rings 2 not shown PTV front trap ETT assembly gang weldment Figure 240 16 PTV plumbing assemblies septumless head shown 7 Inspect the O rings and filter in the filter trap and replace i
29. the side with the visible metal parts faces the oven Figure 240 23 PTV septa 5 Check for leaks out of the cap and tighten the cap if necessary Replacing the liner 1 Remove the head from the inlet 2 Grasp the liner by the Graphpack ferrule Remove the liner and ferrule Jun 2001 Inlets 35 of 46 Agilent 6890 Gas Chromatograph Service Manual 240 Programmed Temperature Vaporization Inlet PTV Replacement procedures 3 Unscrew the assembly tool part no 5182 9750 the ferrule guide from the compression fitting A Figure 240 24 Installing the ferrule onto the new liner 4 Slide the compression fitting onto the longer straight end of the new liner with the threads pointing toward the end of the liner 5 Place a Graphpack 3D ferrule over the end of the liner with the recessed end towards the compression fitting See Figure 240 24 Slide the ferrule towards the fitting until about 2 mm of liner is exposed beyond the ferrule 6 Slide the compression fitting up to the ferrule Screw the ferrule guide gently onto the compression fitting until it is fingertight 7 Remove the ferrule guide then slide the compression fitting The ferrule should now be set with 1 mm of liner exposed Check that the graphite within the ferrule is flush with the top of the metal collar 36 of 46 Inlets Jun 2001 Agilent 6890 Gas Chromatograph Service Manual Programmed Temperature Vaporization Inlet PTV 24
Download Pdf Manuals
Related Search