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GA02330_002_06 - 01/2010 - © Oerlikon Leybold Vacuum
2.5.1 Pumping of Non-condensable Gases
If the process contains mainly permanent gases, the SOGEVACs can be operated
without gas ballast, provided that the saturation vapor pressure at operating
temperature is not exceeded during compression.
If you do not know the composition of the gases to be pumped, and if you can’t
rule out the possibility of condensation, run the pump with gas ballast valve
open in accordance with Section 2.5.2.
2.5.2
Pumping of Condensable Gases and Vapors. Using gas ballast
.
The pumps with gas ballast valves are delivered with the gas ballast valve open.
The SOGEVAC SV300 B can be equipped with following types of gas ballasts :
-
Standard gas ballast
. This gas ballast corresponds to the most important
part of applications .
-
Gas ballast «big flow»
as a variant or accessory is intended for the
applications where more vapours of condensable gases could come into the
pump.
-
Gas ballast "small flow"
for pumping on applications where only few vapours
are to be pumped and where the ultimate pressure with open gas ballast is
important.
-
Gasballast with E.M. valve
(Cat. No. upon request) This kit is intended
for being mounted on pumps on which the gasballast can be driven by an
electromagnetic valve applied at 24 VDC.
A gas ballast kit Including all material required for changing the manual gas
ballast flow to "small", "standard"or "big" is available: P/N 9 714 64 130
With the gas ballast valve open and at operating temperature, the SOGEVAC's
can 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.
Use a screwdriver to 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.
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
until the oil is free of condensed vapors. We strongly recommend operating the
pump in this mode for about 30 minutes after completion of the process.
Operation
