Introduction to Headspace and to the 7694 Headspace Sampler
Principles of Operation
17
Figure 6. Loop fill. S1 is closed. S2 is open (to fill loop).
Loop Equilibration
Both pressure and vent valves are closed for the length of time assigned to this
setpoint.
Injecting the Sample
The sample valve brings the sample loop in line with the carrier gas flow. The
carrier gas flows through the sample loop and the transfer line into the GC inlet
port. This sweeps the sample into the GC.
Carrier
gas flow
Auxiliary gas
flow for vial
pressurization
Mass flow
controller
Pressure
regulator
Pressure
transducer
Pressure
transducer
Vent
S1
S2
1
2
3
4
5
6
Flow
restrictor
Sample
loop
To GC
Headspace
vial
Needle
Open
Closed
Carrier gas
Auxiliary gas
To Next Page
Loading...
