Patent ID: 7481066

Claim:
A vacuum device comprising: a plurality of cryopumps connected with one or more vacuum chambers, a compressor means connected via media supply conduits and media return conduits with the plurality of cryopumps, an adjusting means connected before each of at least one of the cryopumps for controlling the amount of media fed to the corresponding cryopump during cooling, the adjusting means including a throttle device arranged in the corresponding media supply conduit to supply the cryopump with a first amount of media and a valve in a bypass conduit to increase the supply of the media to the corresponding cryopump, a temperature measuring device connected with each of the at least one cryopumps, and a controller connected with the adjusting means and the temperature measuring device of each of the at least one cryopumps, wherein in response to a temperature of one of the cryopumps rising, the controller controls the valve in the corresponding bypass conduit to increase the media supplied and reduce the temperature of the corresponding cryopump.