4.2 Stop Pump
When operation is finished switch off the pump. Proceed as follows:
Isolate the pump from the chamber but keep it running.
In order to prevent any corrosive gases or byproducts inside the pump, do
not stop the pump until after at least 30 minutes after stopping the flow of
process gases.
Switch off the pump.
In order to prevent any residual process gas inside the pump, purge with
N
2
gas for at least one hour after the pump stops.
Low purge gas flow during shut-off may damage the pump.
The pump must only be vented such that atmospheric pressure is
never exceeded.
If the pump has previously pumped hazard ous gases observe Safety
Information in Section 0.4.
In order to prevent a scald accident, it is strictly forbidden to touch the
pump body, the exhaust piping and the hot N
2
piping before they are cold
down completely.
Keep cooling the pump with the cooling water for at least ten minutes;
after that, stop supplying the cooling water, to prevent condensation on
the surface.
4.3 Venting
Open the vacuum system only in completely vented state and only as short
as possible. Otherwise humidity will collect on the inner surfaces. This will
then, during subsequent evacuation, result in significantly longer pump down
times until attaining the desired ultimate pressure.
If during longer downtimes the system shall remain conditioned for a rapid
pumpdown, we recommend to vent the system with dry nitrogen to atmos-
pheric pressure and maintain it in this condition without opening it.
DANGER
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