Patent ID: 7793685
Filing Date: 2010-09-14
Classification: F04D,Y10T

Abstract:
1. An apparatus for establishing and controlling an appropriate low pressure gas mixture, including at least first and second gases, in a vacuum enclosure, the apparatus comprising: at least one secondary pump of a molecular, turbomolecular, or hybrid type; at least one primary pump adapted to deliver to atmospheric pressure; a first pipe having an inlet connected to an outlet of the vacuum enclosure and an outlet connected to a suction inlet of the secondary pump; an intermediate pipe having an inlet connected to a delivery outlet of the secondary pump and an outlet connected to a suction inlet of the primary pump; first control and adjustment means, disposed upstream from the at least one secondary pump, adapted to controlling and adjusting the total gas pressure of the mixture of gases in the vacuum enclosure as a function of a total pressure setpoint; second control and adjustment means distinct from the first control and adjustment means, disposed downstream from the secondary pump, pumping speeds of the different gases in the mixture of gases in the vacuum enclosure; and a control unit for controlling the second control and adjustment means in application of a specific program for adapting the pumping capacity of the secondary pump selectively to the various successive steps of a treatment process taking place in the vacuum enclosure, said control unit including thereby controlling speed of removal of the first and second gases in the vacuum enclosure at the specified step in the treatment process by controlling the pumping speed of the secondary pump to favor pumping at least one of the gases, whereby said apparatus exercises control over both the overall gas pressure in the vacuum enclosure and the proportions of gases in the gaseous mixture of the vacuum enclosure.