Ulvac CRYOPUMP CRYO-U Series Instruction Manual page 51

CRYO-U Cryopump Instruction Manual
®
The maximum quantity of sucked gas which is instantaneously processable is given by the
lim it value at which the cryopump can res
v alue which controls the cryopanel temperature not to exceed 20K is used as the
maximum 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.)
T able 5-2
M
CRYO-U20H
[Example] When U20H is used and the
allowable cros sover pressure
Maximum allowable crossover
pressure (Pa)
In order to restrict the stored quantity of gas an
rec ommended to
Maximum Quantity of Sucked Gas Processable by Cryopump
odel
is calculated as follows
† For reference †
control the actual crossover pressure to 40Pa or less.
ULVAC CRYOGENICS INCORPORATED
tore the evacuation performanc
(Guideline Quantity to the Air)
Maximum quantity of sucked gas spontaneously
processable (Pa•L)
Lim it quantity for the temperature of 20K
vacuum chamber volume is 100L, the maximu
66500 （Pa･L）
≦
1 00（L）
d extend
e. Normally, a
or less
66500
= 665 （Pa）
the regeneration cycle, it is
m
5-5