6.7.2 Pumping of Condensable Gases and Vapors. Using gas
ballast.
With the gas ballast valve open and at operating temperature, the pump pure water
vapor up to the water vapor tolerance indicated in the Technical Data. The pump’s water
vapor tolerance can be increased by raising the operating temperature.
If open the gas ballast valve. The running noise of the pump is slightly louder when the
gas ballast valve is open. Before opening the pump to vapors, ensure that the gas ballast
valve is open and that the pump has been warmed up for about 30 minutes with closed
intake line.
6.7.3
Cyclic process
We emphasize that the number of pump starts should be limited to no more than 6
times per hour. If the process requires cyclic work, we recommend using a pneumatic or
solenoid pilot valve to keep the pump running continuously.
Important
Do not open the pump to condensable vapors until it has warmed to operating
temperature; pumping process gas with a cold pump results in vapors condensing in the oil.
For processes with a high proportion of condensable vapors, slowly open the intake
line, after reaching the operating temperature to prevent excessive quantities of vapor
entering the pump.
One sign of condensation of vapors in the pump is a rise in the oil level during
operation of the pump
During pumping, vapors may dissolve in the oil. This changes the oil properties and
causes a risk of corrosion in the pump. Therefore, do not switch off the pump immediately
after completion of the process. Instead, allow the pump to continue operating with the gas
ballast valve open and the intake line closed. We strongly recommend operating the pump
in this mode for about 30 minutes after completion of the process.
In cyclic process operation, the pump should not be switched off during the intervals
between the individual working phases, but should continue to run with gas ballast valve
open and intake port closed (if possible via a valve).
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