Gas Sampling Valve - Agilent Technologies 7890 Series Advanced Operation Manual

6
Valves

Gas sampling valve

Carrier in
LOAD position
Loop
Sample in
Sample out
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Use a run table entry to ensure that the valve is in the Off
state between runs.
If a valve is configured as a gas sampling valve, it starts a
run automatically when it is switched to the Inject position.
This can be done with a keyboard command or by a
subsequence or clock table entry. You may have two gas
sampling valves installed.
To column
INJECT position
Load position The loop is flushed with a stream of the
sample gas. The column is flushed with carrier gas.
Inject position The filled loop is inserted into the carrier gas
stream. The sample is flushed onto the column. The run
starts automatically.
Carrier gas may be provided by an (optional) auxiliary gas
channel. To do this, configure the column and specify an
Aux # channel as the inlet. The channel then becomes
programmable with four operating modes.
Sampling valves have two positions:
Load position The loop (external for gas sampling, internal
for liquid sampling) is flushed with a stream of the sample.
The column is flushed with carrier gas.
Inject position The filled loop is inserted into the carrier gas
stream. The sample is flushed onto the column. The run
starts automatically.
The sampling valve control parameters are:
Advanced Operation Manual