BOC Edwards EO2K, Instruction Manual

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EO2K, EO4K and EO6K Diffusion Pumps
OP
ERATION
PAGE
36
Issue G 36 Aug 06
4.6.2 Shut down the EO pump
The following method of shut-down ensures that the EO pump is left evacuated and so prevents
absorbtion of air by the pump fluid. When you subsequently start-up, pump down the system through
the backing pipeline to a pressure of 0.5 mbar (50 Pa) or less before you switch on the EO pump heater.
1. Refer to Figure 15. Close the vacuum system isolation or baffle-valve (10).
2. Switch off the EO pump heater, then leave the pump to cool down.
If you do not allow the pump to cool before you admit air, on re-evacuation the pump fluid will
superheat and evolve vapour which will pass into the backing-pipeline.
3. Close the backing-valves.
4. Open the backing-pump air-admittance valve (7) and switch off the backing-pump (8). Do not
switch-off the backing-pump unless air is admitted to the EO pump, otherwise backing-pump oil
may be drawn into the backing line.
5. On water-cooled pumps: When the pump has cooled to ambient temperature, switch off the
cooling-water supply to the pump.
WARNING
Do not admit air into the EO pump through any port until the pump has cooled to
ambient temperature. If you do, the pump fluid may ignite, or expansion of admitted air
can cause hot fluid to be ejected from the pump.