| 摘要 |
In a fast partial regeneration process, the second stage of a cryopump is heated as purge gas is applied to the cyropump. In a test loop, the purge gas is turned off and the roughing valve is opened. If the cyropump is judged to be sufficiently empty of gases from the second stage by being roughed to a sufficiently low pressure in a short period of time the system proceeds to a reconditioning phase. If the system fails the test, however, it is repurged with a burst of warm purge gas and then retested. After passing the emptiness test, the pressure is further reduced by the roughing pump as heat is applied to the second stage. The heat is then turned off for cool down as the system continues to be rough pumped to a base pressure. At about the base pressure, the roughing valve is cycled to maintain the cryopump pressure at a level near to the base pressure. Where multiple cryopumps are coupled to a common roughing pump manifold, they are processed through a partial regeneration sequence in lock step to avoid cross contamination. <IMAGE>
|
