Ulvac CRYO-U Series Instruction Manual page 51

CRYO-U Cryopump Instruction Manual
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The maximum quantity of sucked gas which is instantaneously processable is given by
the limit value at which the cryopump can restore the evacuation performance. Normally,
a v lue which controls the cryopanel tem a
m aximum allowable crossover pressure.
The maximum quantity of sucked gas which is instantaneously processable varies with
the heat load on the cryopump and the quantity of the gas condensed in the cryopump.
(Refer to Table 5-2.)
Table 5-2 Maximum Quantity of Sucked Gas Processable by Cryopump
Model
CRYO-U16,U16P
CR YO-U20P
[Example] When U16P is use
allowable crossover pressure is calculated as follows
Maximum allowable crossover
pressure (Pa)
In order to restr
recommended to control the actual crossover pressure to 40Pa or less.
(Guideline Quantity to the Air)
d and the vacuum chamber volume is 100L, the maximum
† For reference †
ict the stored quantity of gas and extend the regeneration cycle, it is
ULVAC CRYOGENICS INCORPORATED
perature not to exceed 20K is
Maximum quantity of sucked gas spontaneously
processable (Pa•L)
Limit quantity for the temperature of 20K or les
53200（Pa･L)
≦
100（L )
used as the
53200
6650 0
= 532（Pa)
s
5-5