Specifications

79
Operation
The use of vane pumps may result in pumping gases or vapours which are
flammable or that could contaminate the oil. In this case, these products must
be diluted using purges supplied with dry gases, such as nitrogen to avoid
undesirable reactions.
For this purpose, a filtered dry nitrogen supply or other inert gas with the
same characteristics is required:
- condensation point < 22°C,
- dust < 1µm,
- minimum absolute pressure 2 bar.
The purge dilutes pumped gases with a neutral gas:
it makes it possible to limit corrosion in the oil case, condensation and
accumulation of gases in dead spaces of the pump.
Connect the nitrogen supply to one of the unused filling plugs on the oil case
(BSPP 1/8 Gas connection).
Set the nitrogen pressure to approximately 1,2 PSIG (0.1 relativ bar) (flow 50
to 300 SCCM) and the flow rate so as to satisfy the dilution conditions.
Caution: do not generate an excess pressure > 14 PSIG (1 relativ bar).
A neutral gas supply can also be connected via the gas ballast (BSPP 1/8
Gas connection).
Due to the danger represented by the accidental opening of the gas ballast
on a C2 series pump, manual operation of the gas ballast has been disabled.
However, it is possible to disassemble it and connect it directly to a neutral
gas line (BSPP 1/8 Gas connection).
The nitrogen flow rate should be from 900 to 1000 l/h with a pressure of
1 to 1,2 PSIG (0.05 to 0.1 relativ bar).
The bubble device is composed of an air tube with several holes, located at
the bottom of the oil case, which releases bubbles of neutral gas in the oil. In
this way, the oil is saturated with neutral gas, which reduces its capacity to
dissolve pumped gases. The bubbles of neutral gas released make it possible
to eliminate the volatile vapours or acids condensed in the oil. The bubbler
flow also lowers the pumps temperature which slows corrosion.
The gas flow rate is adapted according to the application and the installation,
taking the following criteria into account (flow 60 to 500 SCCM):
• When pumping high quantities of gas, a highly corrosive gas or an easily
condansable gas, it is recommended to use a high nitrogen flow rate.
Caution ! It is assumed that a sufficient quantity of nitrogen is available.
• The pump exhaust circuit must be such that, for discharged flow rates,
pressure drops do not cause an abnormal excess pressure in the oil case.
• The nitrogen flow rate must be such that oil losses have no effect on the
operation of the pump throughout the pumping cycle (the oil level must be
above the lower limit of the sight glass at the end of pumping).
All pumps models
Purges
Oil case purges
Use of purge with gas ballast
C2 models
Purge with gas ballast
Use of the bubbler
Setting
Purges for pumping condensable, corrosive, and
hazardous gases