GA01300_0902 - 04/2006 - © by Leybold Vacuum
23
Operation
4.2
Operation
TRIVAC BCS pumps can pump condensable gases and vapours, provided
that the gas ballast valve (7/5) is open and the pump has attained its ope-
rating temperature.
In connection with the inert gas system (IGS) which is part of the TRIVAC
System, TRIVAC BCS pumps may be operated with an inert gas ballast.
Since the IGS is intended for a reduced gas ballast for purging the pump,
the water vapour tolerance of the pump is reduced depending on the set-
tings to values in the 1 mbar range.
The inert gas supply needs to be opened before allowing the process gas
to enter into the pump.
4.2.1
Non-Condensable Gases
If the process contains mainly permanent gases, the TRIVAC BCS may be
operated without gas ballast (position 0), provided that the saturation
vapour pressure at operating temperature is not exceeded during com-
pression.
If the composition of the gases to be pumped is not known and if conden-
sation in the pump cannot be ruled out, run the pump with the gas ballast
valve open in accordance with Chapter 4.2.2.
4.2.2
Condensable Gases and Vapours
With the gas ballast valve open (position I) and at operating temperature,
TRIVAC BCS pumps can pump pure water vapour up to the water vapour
tolerance specified by the technical data. If the vapour pressure increases
above the permissible level, the water vapour will condense in the oil of the
pump.
When pumping vapours ensure that the gas ballast valve is open and that
the pump has warmed up for approximately 30 minutes with the intake line
closed.
Vapour phases may only be pumped up to the permissible limit
after the pump has attained its operating temperature.
During pumping, vapours may dissolve in the oil. This changes the
oil’s properties and thus there is a risk of corrosion in the pump.
Therefore, don’t switch off the pump immediately after completi-
on of the process. Instead, allow the TRIVAC BCS to continue
operating with the gas ballast valve open and the intake line clo-
sed until the oil is free of condensed vapours.
We strongly recommend operating the pump in this mode for
about 30 minutes after completion of the process.
Caution
Gas ballast valve
