US 5,086,801 AGranted

Vacuum processing system and method

AssigneeMKS Instruments, Inc.

InventorsRoy N. Peacock, Lee E. Vestman

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Abstract

A vacuum processing system and method by which system turbulence is reduced utilizing a vacuum responsive flow controlling valve that is located between a vacuum pump and a vacuum processing chamber to restrict the rate of pumpdown. A valve member of the flow controlling valve, such as a butterfly valve closure plate, is positionally shifted by a pressure differential responsive actuator as a function of the extent to which the pressure in the vacuum processing chamber has been reduced by the pump. During the initial phase of pumpdown, the valve closure member is in its maximally closed position, with evacuation of the vacuum processing chamber occurring solely through a leakage path past the valve member. After a predetermined pressure is reached, the valve member slowly opens as the pressure differential in the actuator increases, until a maximally open position is achieved.

Claims20

Dependent claims

Vacuum processing system comprising:

(A) a vacuum pump;
(B) a vacuum processing chamber enclosing a space that is sealed by the chamber itself relative to the atmosphere during operation of the pump and in which a vacuum effect produced by said pump is utilized;
(C) a vacuum line interconnecting a low pressure side of said vacuum pump with said vacuum processing chamber;
and
(D) a vacuum responsive flow controlling valve means for regulating the rate at which said vacuum processing chamber is evacuated of gases by said vacuum pump, a first portion of said vacuum line extending from said pump to said valve means and a second portion of said vacuum line extending from said valve means to said vacuum processing chamber;
wherein said flow controlling valve means has a valve member disposed in said vacuum line for regulating the flowthrough cross section of the vacuum line and a pressure differential responsive actuator means for shifting the position of said valve member in direct relation to the degree of evacuation of said enclosed space by said pump relative to ambient pressure;
wherein a pressure sensing line is provided as a means for communicating a first side of said pressure differential responsive actuator means with a point in the system at which a pressure exists that at least closely corresponds to that in said vacuum processing chamber, said point in the system being at least as far upstream from said valve member relative to said pump as an upstream end portion of said second portion of the vacuum line that is in proximity to said closed vacuum processing chamber;
wherein a second, opposite side of said actuator means is exposed to ambient pressure;
and wherein a leakage path is provided for communicating said vacuum line at an upstream side of said valve member with said vacuum line at a downstream side of said valve member in a maximally closed position of said valve member.

6 more elements

Vacuum processing system comprising:

(A) a vacuum pump;
(B) a closed vacuum processing chamber;
(C) a vacuum line interconnecting a low pressure side of said vacuum pump with said vacuum processing chamber;
and
(D) a vacuum responsive flow controlling valve means for regulating the rate at which said vacuum processing chamber is evacuated of gases by said vacuum pump;
wherein said flow controlling valve means has a valve member disposed in said vacuum line for regulating the flowthrough cross section of the vacuum line and a pressure differential responsive actuator means for shifting the position of said valve member;
wherein a pressure sensing line is provided as a means for communicating a first side of said pressure differential responsive actuator means with a point in the system at which a pressure exists that at least closely corresponds to that in said vacuum processing chamber, said point being located upstream of said flow controlling valve means relative to said vacuum pump, and said pressure sensing line being the exclusive means by which the pressure differential actuator means is exposed to vacuum suction effects produced by the vacuum pump;
wherein a second, opposite side of said actuator means is exposed to ambient pressure;
and wherein a leakage path is provided for communicating said vacuum line at an upstream side of said valve member with said vacuum line at a downstream side of said valve member in a maximally closed position of said valve member.

6 more elements

Vacuum processing system comprising:

(A) a vacuum pump;
(B) a vacuum processing chamber defining a fully enclosed space during operation of the pump and in which a vacuum effect produced by said pump is utilized;
(C) a vacuum responsive flow controlling valve means for regulating the rate at which the fully enclosed space is evacuated of gases by said vacuum pump;
(D) a first vacuum line means for interconnecting a low pressure side of the vacuum pump with said vacuum responsive flow controlling valve means;
and
(E) a second vacuum line means for interconnecting said vacuum responsive flow controlling valve means with the fully enclosed space;
wherein said flow controlling valve means has a vacuum line section for connecting said first and second vacuum line means, a valve member disposed in the vacuum line section for regulating the flowthrough cross section of the vacuum line section, and a pressure differential responsive actuator means for shifting the position of said valve member;
wherein said pressure differential responsive actuator means includes an actuator member that has one end interconnected with said valve member, a pressure sensing line means for communicating a first side of said actuator member with a point at which a vacuum pressure is to be sampled as a means for displacing the valve actuating member in a direction acting to open said valve member, means for exposing a second, opposite side of said valve actuating member to ambient pressure, means for acting on said valve actuating member in a direction opposite to the vacuum pressure communicated to the first side of the valve actuating member in a manner controlling the rate at which the valve member is opened by said valve actuating member in response to a negative pressure differential between ambient pressure and that sampled by said pressure sensing line so as to produce controlled progressive opening of the valve member as a result of incremental increases in said negative pressure differential;
and wherein a leakage path is provided for communicating said first vacuum line means with said second vacuum line means in a maximally closed position of said valve member.

6 more elements

Vacuum processing system comprising:

a vacuum responsive flow controlling valve means for regulating the rate at which a fully enclosed space is evacuated of gases by a vacuum pump;
a first vacuum line means for interconnecting a low pressure side of a vacuum pump with said vacuum responsive flow controlling valve means;
and a second vacuum line means for interconnecting aid vacuum responsive flow controlling valve means with the fully enclosed space;
wherein said flow controlling valve means has a vacuum line section for connecting said first and second vacuum line means, a valve member disposed in the vacuum line section for regulating the flowthrough cross section of the vacuum line section, and a pressure differential responsive actuator means for shifting the position of said valve member;
wherein said pressure differential responsive actuator means includes an actuator member, a pressure sensing line means for communicating a first side of said actuator member with a point at which a vacuum pressure is to be sampled as a means for displacing the valve actuating member in a direction acting to open said valve member, means for exposing a second, opposite side of said valve actuating member to ambient pressure, means for acting on said valve actuating member in a direction opposite to the vacuum pressure communicated to the first side of the valve actuating member in a manner controlling the rate at which the valve member is opened by said valve actuating member in a manner controlling the rate at which the valve member is opened by said valve actuating member in response to a negative pressure differential between ambient pressure and that sampled by said pressure sensing line so as to produce controlled progressive opening of the valve member as a result of incremental increases in said pressure differential;
and wherein a leakage path is provided for communicating said first vacuum line means with said second vacuum line means in a maximally closed position of said valve member.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/674,433Filed 19 Nov 1990 · continuation
Priority: 6 Nov 1989
Granted: 11 Feb 1992
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

G05D 16/0625
The sensing element being a bellow: acting indirectly on the obturator, e.g. by a lever
Y10S 137/907
Fluid handling: vacuum-actuated valves
Y10T 137/0379
With control of flow by a condition or characteristic of a fluid: by fluid pressure
Y10T 137/7781
Line condition change responsive valves: with separate connected fluid reactor surface