Patent ID: 11920576
Assignee: SUMITOMO HEAVY INDUSTRIES, LTD.
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F | IPC F

Claim 2:
3. A cryopump including an accommodation space for a condensed layer of gas, the cryopump comprising:
a first-stage cryopanel that is cooled to a temperature higher than a condensation temperature of the gas and includes an inner surface of the first-stage cryopanel disposed so as to surround the accommodation space;
a second-stage cryopanel that is cooled to a temperature equal to or lower than the condensation temperature of the gas, on which the condensed layer of the gas is deposited, and that is disposed so as to be surrounded by the inner surface of the first-stage cryopanel together with the accommodation space;
a cryopump intake port that allows a passage of a first-stage heat load incident on the inner surface of the first-stage cryopanel from outside the cryopump and the gas entering the accommodation space from outside the cryopump;
a second-stage cryopanel monitor that monitors an amount of condensed gas in the accommodation space based on a change in the first-stage heat load;
a cryocooler including a first cooling stage thermally coupled to the first-stage cryopanel and a second cooling stage thermally coupled to the second-stage cryopanel; and
a first-stage temperature controller that controls an operating frequency of the cryocooler to cool the first-stage cryopanel to a first-stage target temperature, wherein
the second-stage cryopanel monitor compares the operating frequency of the cryocooler with a threshold value, and determines that the amount of condensed gas exceeds a reference value in a case where the operating frequency of the cryocooler falls below the threshold value.