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Technical Description
Anti-Suckback Device
54/140 Dual Stage Rotary Vane Pumps User Manual/ 87-900-937-01(L)
To avoid this, during compression at the second stage, atmospheric
air is let into the pump through an adjustable valve, or “gas ballast
valve”, located at the top of the pump.
In this way, the discharge valve of the second stage opens through
the effect of the atmospheric air before the partial pressure of the
vapor reaches saturation point, thus preventing condensation from
occurring. The vapors are expelled mixed with air.
Anti-Suckback Device
The pump is equipped with a special anti-suckback device to avoid
air pressure rises and/or oil backflow towards the evacuated vessel
when the pump is switched off. This device has a shutter which
automatically closes the suction duct.
In this way the pump and vacuum system are completely isolated
from each other and air can enter the pump without any risk for the
vacuum produced in the system.
The device includes some special features, namely:
drive obtained avoiding any form of contamination of the inlet
duct by fluids (oil and/or air) used to command the shutter.
Thanks to this, when the pump is started again, the pumpdown to
vacuum conditions is extremely fast as these contaminants are
not present and no degassing is therefore required;
suction flange maintained closed even when the pump is idle, so
that pollutants cannot enter from the environment and no oil can
overflow from the pump.
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