Ulvac CRYO-U Series, Instruction Manual

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Maintenance
8-4
ULVAC CRYOGENICS INCORPORATED
8.3 Cleaning the Cryopump
CAUTION
WARNING
When it seems that the cryopump has been used to evacuate toxic or dangerous materials,
you must contact the safety supervisor beforehand, and confirm a safe recovery method.
WARNING
The majority of the cause deteriorating the perf cryopump is contamination on the
80K shield and the 80K baffle. It's recommended to check the temperature of these parts once a
week with the main valve closed, in order to observe the degree of contamination. When
removing the cryopump from the vacuum chamber for maintenance of the refrigerator etc,
inspect the 80K shield and the 80K baffle at the same time.
ormance of the
◆
Cleaning of Inner kit
Especially the 80K baffle tends to get contaminated most. Perform the 80K baffle cleaning as
follows:
1. Remove the cryopump from the vacuum chamber and put the cryopump on the floor with the
mounting flange up. At this time, be sure to support the cryopump not to fall down.
2. Wipe out the 80K baffle with clean cloth dipped in alcohol.
When 15K cryopanel is seriously corroded or contaminated, replace with new one.
Handle 15K cryopanels with care as they are soft and easily deformed.
Do not wipe the blackened surface of the 80K shield with alcohol. Otherwise the blackened
surface may be peeled off with a solvent.
◆
Maintenance of the pressure relief valve
If the pressure relief valve is not cleaned for a long time, it may fail to open at required
pressure.