Siemens PGC 302 Edition II Manual page 131

Liquid injection valve
Liquid injection valve
The liquid injection valve can be used to automati-
cally inject a constant quantity of liquid sample fol-
lowed by fast, complete vaporization. Small gas
quantities can also be injected using the valve.
The liquid injection valve consists of three components:
n Temperature-controlled vaporization system
n Sample flow unit with seal
n Pneumatic drive
In the purging position, the sample flows permanently
through the cross hole or the ring groove of the injec-
tion tappet. When injecting, the tappet is pushed pneu-
matically into the vaporization area. The liquid in the
cross hole or ring groove is vaporized and is flushed by
the carrier gas into the column. The tappet is then
shifted pneumatically back into its original position.
Sample then passes through the injection hole again.
Carrier gas
2 - II
Control air
Sample
Technical data
Max. vaporization tempera-
ture
Injection volume
Ambient temperature
Material of parts in contact
with the sample
Control pressure
Sample pressure
Connections
Vaporization system
The vaporization tube is inserted with an aluminium
sleeve into the heating plate whose temperature is regu-
lated by a heating cartridge and a Pt100 temperature
sensor.
The carrier gas is routed via the pipe into the vaporizer
and heated up to the vaporization temperature in the
process. The vaporizer is adjusted such that the carrier
gas inlet is opposite the injection hole.
Sample flow unit
The sample flow unit is isolated from the vaporizer and
the pneumatic drive by lenticular Teflon gaskets. An
adjustable adapter and cup springs position the Teflon
gaskets with a constant pressure and compensate tem-
perature expansion effects and gasket wear.
Classified version
In the classified version, the heating cartridges and tem-
perature sensor are pressurized. Their lines lead directly
into the venting trunking behind the analyzer area and
are purged together with the electronics area. The sen-
sor of a safety temperature limiter is additionally in-
serted into the heating plate and switches the heater off
if the plate reaches the ignition class temperature.
60 ... 400 °C;
with explosion-proof analyzers
according to the temperature class
0.3 to 9.5 µl
-20 ... +150 °C
V4A, mat. No. 1.4571
Hastelloy, Monel or special
4 to 6 bar
Max. 50 bar,
recommended 5 ... 10 bar
For pipe with 3 mm outer diameter
Register8.vp Stand: 20.11.2000