Varian VHS-250, Инструкция по эксплуатации

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VHS-4, VHS-6 and VHS-250 Diffusion Pumps
3-2
D
R
A
FT 3/9
/
05
❑
Ensure that the cooling water flow is adequate and unobstructed. In areas where
the mineral content of the water is high or where there is considerable sediment,
it may be advisable to install water filters.
3.3 Cleaning
Complete cleaning of the pump may be required due to the gradual deterioration of pump
fluids. Removal of the pump from the system is necessary.
To clean the pump:
1. Turn off the power and disconnect the power supply plug.
2. Allow the pump to cool, then turn off the cooling water and disconnect the cooling
lines.
3. Unbolt the inlet flange and foreline connections.
4. Remove the pump from the system.
5. Drain the diffusion pump of all fluid.
6. Remove all O-rings, then remove the cold cap assembly, the jet assembly, and the
foreline baffle from the pump.
7. Thoroughly clean the diffusion pump body interior and the jet assembly using acetone
followed by an isopropyl alcohol rinse.
8. Dry the pump and the jet assembly with clean, dry, oil-free compressed air.
9. Install the foreline baffle, the jet assembly, and the cold cap assembly in the pump body.
❑
Verify that the ejector nozzle is properly aligned with the foreline.
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Verify that the cold cap is properly installed on the jet assembly. The space between
the underside of the cold cap and the outside of the jet cap should be uniform.
10. Reinstall the diffusion pump in the system using all new O-rings.
11. Charge the pump with the proper amount of fluid.
12. Reconnect the water cooling lines and the power supply.
13. Evacuate the diffusion pump with the appropriate mechanical pump and turn on the
cooling water.
14. After the pump has been evacuated to a pressure below 0.5 Torr (.66 mbars), turn on the
power to the diffusion pump.