Gow-Mac 5900 Series, Operating Manual

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Series 5900 DID GC
1019, Rev. 1
29
SECTION 7 - VALVES
7.1 General
The SERIES 5900 DID GC is equipped with a maximum of four (4) gas valves. They
must be treated with care.
WARNING
VALVES HAVE UPPER TEMPERATURE LIMITS WHICH, IF EXCEEDED, CAN
PERMANENTLY DAMAGE INTERNAL COMPONENTS.
UPPER TEMPERATURE LIMIT FOR VALCO VALVES IN THIS GC: 175 °C
UPPER TEMPERATURE LIMIT FOR ACTUATORS IS 150 °C
7.2 All helium actuators are high temperature type (T). When ordering a replacement
valve, make sure to order a low temperature valve with high temperature actuators.
7.3 Gas Sampling Valves
The gas sample valves are used to introduce gas samples into the chromatograph on
a reproducible basis. The sample may be taken from a static system or from a flowing
stream. Valves are also used for column back-flushing, heart-cutting, column selection,
sample selection and detector switching.
A. Sample Isolation Valve: The 4 port sample isolation valve is included in every Series
5900 GC. The sample isolation valve allows the operator to purge the sample from the
source to vent in the CW position while purging the GC with carrier helium. This is a
great troubleshooting tool as the GC can inject the helium carrier gas and check for “leak
peaks”. If the GC flow system is leak tight, the injected baseline should result in a flat
line void of any atmospheric peaks. The CCW position will allow the sample to go to the
sample injection valve for analysis injection.