Operation
Selection of vaporization temperature
The vaporization temperature can be set independent of
the oven temperature. It is selected according to the
sample and its boiling point. The most favourable va-
porization temperature must be determined experimen-
tally. The amount by which the vaporization tempera-
ture should be above the boiling point of the sample de-
pends on the heat of vaporization of the sample. Sam-
ples with a high heat of vaporization, e.g. aqueous sam-
ples, only vaporize sufficiently fast for chromato-
graphic purposes at high temperatures (above 200 °C),
as shown in the Fig. below.
Manual injection
It is possible to inject samples manually into the vapor-
izer using an injection syringe. The liquid injection
valve must first be adapted: remove the valve body to-
gether with the valve mechanics and the Teflon gasket
in the vaporizer. Instead, insert a septum (diameter
9 mm, thickness 4 mm) into the gasket area of the va-
porizer, and screw an injection syringe head with pres-
sure washer onto the vaporizer.
DANGER: Explosion protection
What you have to observe with the clas-
sified PGC 302 so that the explosion pro-
tection is not cancelled:
The sensor of the safety temperature limiter
must be inserted into the heating plate and
protected from removal using a screw.
The protective tube for the heating cartridge
and temperature sensor must be fitted cor-
rectly (see maintenance).
The exhaust holes in the protective tube
must not be closed.
CAUTION: Filter required
The tappet and gaskets close faster if the
sample contains solid particles! In this case,
a filter is required upstream of the injector.
We recommend a filter with a separating ca-
pacity of
- 98% for 0.3-µm particles with
liquid samples
- 99.99% for 0.1-µm particles with
gaseous samples
Siemens sample preparation units contain
such filters!
Register8.vp Stand: 20.11.2000 2 - III
Liquid injection valve
Temperature dependence
of vaporization speed of water
Vaporization temperat. 100°C
130°C
160°C
200°C
200°C
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