Ulvac CRYOPUMP CRYO-U Series Instruction Manual page 74

Maintenance
6. Warm up the cryopump (refrigerator unit). Allow the 15K cryopanel of the cryopump (the
second stage) and the inside of the refrigerator to warm up to room temperature. It
usually takes hours for the inside of the refrigerator to warm up. The recommended time
is for eight hours or more.
When the cryopump is exposed to the atmosphere while warming up, the charcoal on the
15K cryopanel could adsorb large amounts of moisture and it would bring about extension of
the regeneration time. Care must be taken to prevent this situation.
Performing the assisted warm-up procedures described in Section 6.3 of this manual can
shorten the warm-up time.
Before proceeding to next, make sure that the 15K cryopanel has reached room
temperature.
7. Connect the helium bottle and the regulator. Replace the air remained between the
helium bottle valve and the regulator with helium gas as instructed in Section 8.4 –
Charging Helium Gas.
Use helium gas with purity of 99.999％ or above.
8. Perform decontamination procedures as follows:
Before proceeding decontamination, prepare the rough pumping system as indicated in
Figure 8-4. A roughing pump with the pumping speed of 20L/min or more and the
ultimate pressure of 10Pa or less is recommended.
Cryopump
Figure 8-4 Cryopump Decontamination Procedure (1)
8-10
CAUTION
†For Your Information†
Charging Adopter
Flexible Hose
XXXXXXXX
******
Compressor Unit
Cold head cable
ULVAC CRYOGENICS INCORPORATED
Charging Hose
Ｖ２
ＳＵＰＰＬＹ
Charge helium gas
Ｖ１
ＲＥＴＵＲＮ
Release helium gas
Ｖ３
To Roughing Pump
Regulator
Bottle Valve
High Pressure
Low Pressure
High Purity Helium Bottle