Fluid handling – Systems – Dividing into parallel flow paths with recombining
Reexamination Certificate
2000-07-10
2001-09-25
Hepperle, Stephen M. (Department: 3753)
Fluid handling
Systems
Dividing into parallel flow paths with recombining
C137S601150, C137S601170, C137S614110
Reexamination Certificate
active
06293306
ABSTRACT:
TECHNICAL FIELD
The present invention relates to gate valves for applied processing systems and, more particularly, to a gate valve with throttling control for improved control of vacuum pressure with applied processing chambers.
BACKGROUND ART
My U.S. Pat. No. 5,884,899 entitled “HalfProfile Gate Valve ,” discloses an improved gate valve with a low-profile design for economy of size, as discussed therein. This reference is incorporated herein. The gate valve of my '899 patent is designed for “opened” and “closed” positions to allow for either full flow or no flow of gaseous fluids through the valve. The present invention improves upon the design of my '899 patent gate valve by providing therewith a throttling valve to provide for variable gas flow in order to precisely control the operating parameters, such as pressure and temperature, within a process chamber.
Throttling butterfly valves and vacuum pressure control throttling multi-vane valves are also known in the art and are commonly used for controlling process variables. Butterfly valve have the advantage of being relatively simple in design, which reduces their cost and maintenance, but they have limited ability to achieve a linear conductance response. Multi-vane throttle valves, such as the Vari-Q Throttle Valve sold by MeiVac, Inc. of San Jose, Calif., USA, provide more precise control than butterfly valves, but are much more complicated in design. Thus, a need exists for a simple throttle valve design that achieves more linear conductance response.
DISCLOSURE OF INVENTION
Briefly described, the throttle gate valve of the present invention comprises a housing defining a thru-opening for controlling vacuum within a process chamber, a gate valve movable between open and closed positions, in the closed position closing off the thru-opening to prevent the passage of process gases, a linear conductance throttle vane movably mounted within the thru-opening for throttling flow of gases through the thru-opening when the gate valve is in its open position, and a drive mechanism for moving the throttle vane in order to vary flow of the process gases, the drive mechanism including a linear drive actuator extending into the housing and including a bellows shield to prevent escape of gases where the linear drive actuator extends into the housing.
The linear conductance throttle valve includes at least one vane that extends across the thru-opening and is rotatably mounted at opposite ends for angular movement between a multiplicity of positions. Preferably, the linear conductance throttle valve includes more than one vane, each symmetrically mounted about its axis of rotation. In this manner, the linear conductance throttle valve provides a substantially linear response across the thru-opening within a pre-selected operating range.
According to an aspect of the invention, the housing includes first and second side chambers, one on each side of the throttle vane. Each side chamber is defined at least partially by an interior wall that provides a rotatable support for the throttle vane, the linear drive actuator extending into the first side chamber and connecting to the throttle vane for rotation of the vane, the housing further including a port providing fluid communication between the first side chamber and the thru-opening. When the thru-opening is at vacuum, so too is the first side chamber.
Preferably, the housing further includes a gate valve chamber for positioning the gate valve in its closed position, and the port provides fluid communication between the first side chamber and the thru-opening via the gate valve chamber. The port is formed to prevent fluid communication between the first side chamber and the process chamber when the gate valve is closed.
According to another aspect of the invention, the housing further includes a gate valve chamber for positioning the gate valve in its closed position, and the port provides fluid communication between the second side chamber and the thru-opening via the gate valve chamber.
According to another embodiment of the invention, the throttle vane assembly is provided for controlling vacuum to a process chamber and includes a housing defining a thru-opening, a throttle vane rotatably mounted in the thru-opening for controlling vacuum pressure to the process chamber, the housing including a side chamber defined at least partially by an interior wall that rotatably supports the throttle vane, a drive mechanism for rotating the throttle vane, the drive mechanism extending into the side chamber from exterior of the housing and drivingly connecting to the throttle vane for rotation thereof, and the housing further including a port for providing fluid communication between the thru-opening and the side chamber, whereby a pressure differential can be avoided between the thru-opening and the side chamber.
These and other features, objects, and advantages of the present invention will become apparent from the following description of the best mode for carrying out the invention, when read in conjunction with the accompanying drawings, and the claims, which are all incorporated herein as part of the disclosure of the invention.
REFERENCES:
patent: 1332000 (1920-02-01), Pfau
patent: 2053668 (1936-09-01), Kinzie et al.
patent: 5765592 (1998-06-01), Karlicek
patent: 5884899 (1999-03-01), Brenes
patent: 6173939 (2001-01-01), Dottavio et al.
Brochure for “Model 1800 Self Tuning Downstream Pressure Control System,” Edwards Product Information, Bulletin #1019 (8 pages).
Brochure for “Intellisys, Adaptive Pressure Control for the Next Millennium,” Nor-Cal Products, Inc., Jul. 1999 (5 pages).
Brochure for “MeiVac GVQ Series Throttling Gate Valves,” MeiVac (4 pages).
Brochure for “Throttle Valves & Controllers,” MeiVac, Inc. (12 pages).
Brochure for “Throttle Isolation Valves, Type 656A,” MKS Instruments (3 pages).
Brochure for “Downstream Pressure Controllers,” MKS (5 pages).
Flehr Hohbach Test Albritton & Herbert
Hepperle Stephen M.
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