Ulvac CRYO-U Series, Instruction Manual, Page: 99 / 106

CRYO-U ® Cryopump Instruction Manual
ULVAC CRYOGENICS INCORPORATED E-3
The ideal refrigeration ability “Q
ideal
” is as follows when indicating the period of one
cycle as “t” minutes:
Q
ideal =
W / t
In the actual refrigerator, the structure with two stages is adopted in order to gain cryogenic
temperature of 15K or less as shown in Figure E-3. In order to simplify structure, the
regenerator is built into the inside of the displacer, and it is unifying. Moreover, since
difference pressure is not applied to seals on the 1st stage and 2nd stage, the structure
where the load to the seal is light has been adopted. Therefore, a long-lived, high reliability
is acquired.