Vacuum pumping systems
AssigneeThe BOC Group, Inc.
InventorBarrie Dudley Brewster
Life of this patent
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Abstract
A vacuum pumping system for use with a process chamber. The pumping system has a first vacuum pump whose inlet is adapted for communication via a first line with a chamber outlet and a second vacuum pump whose inlet is adapted for communication via a second line with a first pump outlet. A third line containing a throttle valve is linked to the first and to the second lines in parallel to the first vacuum pump to enable variable amounts of gas to flow through the throttle valve from the second line to the first line depending on the position of the throttle valve.
Claims7
A vacuum system for use with a process chamber having a chamber outlet, said vacuum pumping system comprising:
- first and second vacuum pumps, each having an inlet and an outlet;
- first, second and third lines;
- the first line in direct fluid flow communication between said inlet of the first vacuum pump and said chamber outlet, the second line communicating between said inlet of the second vacuum pump and said outlet of the first vacuum pump;
- and
- the third line linked to the first and to the second lines in parallel to the first vacuum pump;
- and
- means to regulate the flow of gases in the system consisting of a single throttle valve situated in the third line such that, when it is at least partially open, gas will flow from the second line back to the first line by means of the pressure differential across said first pump.
Dependencies are inferred from the claim text.