How The Hs Pressurizes A Vial; Fill At Flow To Pressure; Fill To Pressure - Agilent Technologies 7697A Advanced Operation Manual

How the HS Pressurizes a Vial

Fill at flow to pressure

Fill to pressure

Advanced Operation
All 7697A HS provide several techniques for pressurizing the
sample vial. In addition to simply heating the vial, which
may generate enough internal pressure on its own, the HS
can provide additional gas to help with extraction. This gas
comes from the Vial pressure fitting on the HS back panel,
and can be different from the carrier gas used to move the
sample onto the column. While the default vial
pressurization method is often sufficient, the alternative
techniques may be useful in some applications. See
below.
Transfer
line
Sample loop
Carrier gas
Figure 6 Pressurizing the vial
This is the default vial fill mode. In this mode, the HS
maintains a specified flow rate of carrier gas into the vial
until the pressure inside the vial reaches the fill pressure
setpoint. The HS maintains this pressure for the hold time.
At the end of the hold time, the sample loop fill begins.
In this mode, the HS fills the vial as rapidly as possible to
the target fill pressure setpoint, then maintains this pressure
for the specified hold time. At the end of the hold time, the
sample loop fill begins.
How the 7697A Headspace Sampler Works
6 port valve
4
3
5
2
6
1
Vial
pressurization gas
2
Figure 6
Sample probe
19