Cryopump and control method for cryopump
AssigneeSumitomo Heavy Industries, Ltd.
InventorKakeru Takahashi
Life of this patent
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Abstract
A cryopump includes a cryopump container, a pressure sensor that measures a pressure in the cryopump container and generates time-series pressure data indicating the measured pressure, a vent valve that is provided on the cryopump container, is electrically operable to open and close, and is capable of being mechanically opened by a differential pressure between inside and outside the cryopump container, and a controller that, during cryopump regeneration, detects stabilization of the measured pressure based on the time-series pressure data from the pressure sensor and controls the vent valve to open upon detection of the stabilization of the measured pressure.
Claims12
A cryopump comprising:
- a cryopump container;
- a pressure sensor that is configured to consecutively measure a pressure in the cryopump container and generate time-series pressure data including at least two measured pressure values measured at time points different from each other;
- a vent valve that is provided on the cryopump container, is electrically operable to open and close, and is capable of being mechanically opened by a differential pressure between inside and outside the cryopump container;
- a purge valve that is provided on the cryopump container;
- and
- a controller configured to
- open the purge valve to supply a purge gas to the cryopump container,
- perform, responsive to the opening of the purge valve, iterative calculations of a changed amount of the at least two measured pressure values from the time-series pressure data measured,
- perform, responsive to the performing of the iterative calculations of the changed amount of the at least two measured pressure values, iterative comparisons of the changed amount of the at least two measured pressure values with a changed amount threshold, the iterative comparisons occurring in conjunction with the iterative calculations, and
- perform control of the vent valve to open when the iterative comparisons confirm that the changed amount of the at least two measured pressure values is less than the changed amount threshold.
A control method comprising:
- opening a purge valve of a cryopump to supply a purge gas to a cryopump container of a cryopump;
- consecutively measuring, with a controller and a pressure sensor, a pressure in the cryopump container during the supplying of the purge gas to the cryopump container to generate time-series pressure data including at least two measured pressure values that are measured at time points different from each other;
- responsive to the opening of the purge valve, iteratively calculating, with the controller, a changed amount of the at least two measured pressure values from the time-series pressure data;
- responsive to the iteratively calculating, iteratively comparing, with the controller, the changed amount of the at least two measured pressure values with a changed amount threshold;
- and
- controlling, with the controller, a vent valve of the cryopump to open when the iterative comparisons confirm that the changed amount of the at least two measured pressure values is less than the changed amount threshold.
A non-transitory computer-readable medium comprising instructions that, when executed by a controller, cause the controller to perform a set of operations comprising:
- opening a purge valve of a cryopump to supply a purge gas to a cryopump container of the cryopump;
- controlling a pressure sensor to consecutively measure a pressure in the cryopump container during supplying the purge gas to the cryopump container to generate time-series pressure data including at least two measured pressure values that are measured at time points different from each other;
- responsive to the opening of the purge valve, iteratively calculating a changed amount of the at least two measured pressure values from the time-series pressure data;
- responsive to the iteratively calculating, iteratively comparing the changed amount of the at least two measured pressure values with a changed amount threshold;
- and
- controlling a vent valve of the cryopump to open when the iterative comparisons confirm that the changed amount of the at least two measured pressure values is less than the changed amount threshold.
Dependencies are inferred from the claim text.