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5 of 24
Jun 2001
Agilent 6890 Gas Chromatograph Service Manual
Thermal Conductivity Detector (TCD)
330
Theory of operation
EPC detector
The EPC TCD has one flow line for the makeup/reference gas. After an initial
filter frit, it splits into two paths. Each line has a proportional valve controlled
by a pressure sensor, and a non-adjustable restrictor frit. In addition, the
switching gas line has a switching valve that switches paths through the TCD
cell several times a second. The switching line oscillates between two
flowpaths, one for each channel of the TCD cell. The makeup gas line sweeps
past the end of the column and carries the column effluent into the TCD cell.
Figure 330-4
EPC TCD flow diagram
Manually controlled detector
The manually controlled TCD has a pneumatic supply line for the switching
gas (also called modulating or reference gas) flow and one for the makeup
gas. Both of the lines have pressure regulators, an on/off solenoid valve and
a non-adjustable restrictor frit. In addition, the switching gas line has a
Filter
frit
Makeup and
reference gas in
Proportional
valves
Pressure
sensors
Restrictors
Reference
switching
valve
Vent
Makeup flow
PS
PS
Pressure
control loops
Содержание 6890 Series
Страница 1: ...6890 Series Gas Chromatograph Service Manual ...
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Страница 27: ...24 of 24 Jun 2001 Contents Contents Agilent 6890 Gas Chromatograph Service Manual ...
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Страница 195: ...260 Solvent Vapor Exit Accessory Leak testing 10 of 10 Jun 2001 Inlets Agilent 6890 Gas Chromatograph Service Manual ...
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Страница 389: ...360 Auxiliary EPC Replacement procedures 16 of 16 Jun 2001 Detectors Agilent 6890 Gas Chromatograph Service Manual ...
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Страница 479: ...520 Gases Supplying valve actuator air 14 of 14 Jun 2001 Site Preparation Agilent 6890 Gas Chromatograph Service Manual ...
Страница 485: ...530 Power Grounding 6 of 6 Jun 2001 Site Preparation Agilent 6890 Gas Chromatograph Service Manual ...
Страница 491: ...540 Instrument Specifications Detectors 6 of 6 Jun 2001 Site Preparation Agilent 6890 Gas Chromatograph Service Manual ...
Страница 492: ...600 Performance Verification How to check the performance of the 6890 instrument 610 Checkout Chromatograms ...
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Страница 555: ...840 Shutdowns 10 of 10 Jun 2001 Error Codes and Internal Diagnostics Agilent 6890 Gas Chromatograph Service Manual ...
Страница 580: ...900 Remote Access Remote Access information was not available for this printing ...
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Страница 637: ...1110 Valves Liquid sample valves 6 of 6 Jun 2001 Valves Agilent 6890 Gas Chromatograph Service Manual ...
Страница 647: ...1120 Valve Box Removing the valve box assembly 10 of 10 Jun 2001 Valves Agilent 6890 Gas Chromatograph Service Manual ...
Страница 675: ...1150 Troubleshooting Pressure check 6 of 6 Jun 2001 Valves Agilent 6890 Gas Chromatograph Service Manual ...
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Страница 717: ...1225 Main Board 6890N Fuses 6 of 6 Jun 2001 Electrical Agilent 6890 Gas Chromatograph Service Manual ...
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