Ulvac CRYO-U Series, Instruction Manual

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Operation
5-2 ULVAC CRYOGENICS INCORPORATED
5.3 Pressure Buildup Test
１．
When the pressure inside the cryopump reaches 40Pa, close the roughing valve
（
RV1
）
and check the pressure buildup.
If the pressure buildup value stayed less than 6.5Pa for five minutes, the roughing
process has been completed. If it increased 6.5Pa or more in five minutes, repeat the
rough pumping procedure described in Section 5.2.
２． After the test completed, rough pump the cryopump to 40Pa.Then close the roughing
valves (RV1) and turn off the roughing pump.
5.4 Startup and Cooldown
１． Start up the compressor unit.
†
For Your Information
†
When the cooling process reaches the stable state, the rubbed sound becomes small.
Oppositely, the inhalation sound and the exhalation sound of helium gas like choo-choo
become loud.
２． When the 15K cryopanel is cooled to 20K or lower and the 80K shield is cooled to 130K
or less, the cryopump is ready to pump down. Refer to Table 1-1 for cooldown time of
the cryopump. If MBS-C CRYO-METER is attached on your cryopump, the temperature
of the 15K cryopanel is displayed as shown in Table 5-1. As MBS-C has the function by
which the thermocouple electromotive force is output directly, the temperature of 80K
shield can be measured with K thermocouple as well. (Please refer to MBS-C instruction
manual for more details.) If Hydrogen Vapor Pressure Gauge is mounted on 15K
cryopanel and K thermocouple is mounted on 80K shield, refer to Table 5-1 for their
indications and outputs.