Fluid handling – Self-proportioning or correlating systems – Self-controlled branched flow systems
Reexamination Certificate
2000-09-20
2001-10-02
Hepperle, Stephen M. (Department: 3753)
Fluid handling
Self-proportioning or correlating systems
Self-controlled branched flow systems
C251S073000, C251S094000
Reexamination Certificate
active
06296008
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to a type of valve which may be termed a “switchover valve”, and more particularly to a valve for automatically switching over from one supply of pressure fluid in response to failing or failure thereof to another supply of pressure fluid for continuity of operation.
The invention is especially concerned with a valve for switching over delivery of a gas (e.g. oxygen, nitrogen) from a bottled supply thereof under pressure upon depletion of the supply (the content of the bottle) to another bottled pressurized supply of the gas for continuity of supply of the gas for whatever the ultimate use thereof may be, one example being switchover of bottles supplying oxygen for the medical need of a patient. Another example is switchover of bottles of gas used for industrial purposes, such as the use of bottles of oxygen and other gases for welding purposes.
Reference may be had to the following U.S. Patents disclosing valves purportedly for a generally similar purpose, often referred to as “shuttle” valves:
U.S. Pat. No.
Date of Issue
Title
3,533,431
Oct. 13, 1970
Snap Acting
Valve Mechanism
4,253,481
March 3, 1981
Cushioned Shuttle
Valve
4,674,526
June 23, 1987
Switching Valve
5,127,426
July 7, 1992
Valve
SUMMARY OF THE INVENTION
Among the several objects of the present invention may be noted the provision of a switchover valve, for automatically switching over from one supply of pressure fluid (e.g. gas) to another supply in response to a drop in pressure of the one supply, which is substantially safe against false switchovers; the provision of such a switchover valve having means positively holding against switchover except on a drop in pressure below a predetermined value of the supply; the provision of such a switchover valve wherein the holding means is adjustable for setting different values for the switchover pressure drop; the provision of such a switchover valve which is immune to reverse flow; and the provision of such a switchover valve which is relatively economical to manufacture and reliable in operation.
Generally, a switchover valve of the present invention for switching over from one supply of pressure fluid to another supply thereof in response to failing or failure of the one supply comprises a valve body having two inlets for connection thereto of the respective supplies and an outlet. A valve member is movable in the valve body between a position establishing communication for delivery of fluid from one inlet to the outlet and blocking flow from the other inlet to the outlet and a position establishing communication for delivery of fluid from the other inlet to the outlet and blocking flow from the one inlet to the outlet. The valve member is subject to pressure of fluid supplied to the one inlet for moving it from the first-mentioned position to the second-mentioned position and to pressure of fluid supplied to the other inlet for moving it from the second-mentioned position to the first-mentioned position. The switchover valve also comprises a latch for latching the valve member in one or the other of its positions. The latch is movable between a latching position engaging the valve member and a retracted position clearing the valve member for movement. The latch is biased toward the retracted position and is held in the latching position against the bias by pressure of fluid delivered by the valve member in one or the other of its positions. The latch moves to the retracted position under the bias upon a drop in pressure of fluid delivered by the valve member in either of its positions.
More particularly, a valve of this invention comprises a valve body having a first cylinder therein, the body having two inlets for connection thereto of the respective supplies. One inlet communicates with one end of the first cylinder and the other inlet communicates with the other end of the first cylinder. An outlet in the body extends radially outward from the first cylinder generally at the center of length of the first cylinder. A second cylinder in the body extends outward from the first cylinder intermediate the ends of the first cylinder. The second cylinder is open to the outlet for exposure to the pressure of fluid in the outlet. A piston constituting a switchover valve member is slidable in the first cylinder between a position establishing communication for delivery of fluid from one inlet to the outlet and blocking flow from the other inlet to the outlet and a position establishing communication for delivery of fluid from the other inlet to the outlet and blocking flow from the one inlet to the outlet. The piston is subject to pressure of fluid supplied to the one inlet for moving it from the first-mentioned position to the second-mentioned position and to pressure of fluid supplied to the other inlet for moving it from the second-mentioned position to the first-mentioned position. A latch piston is slidable in the second cylinder and has a latch thereon for latching the valve member in one or the other of its positions. The latch is movable between a latching position engaging the valve member and a retracted position clearing the valve member for movement. The latch is biased toward the retracted position and is held in latching position against the bias by pressure of fluid delivered by the valve member in one or the other of its positions. The latch moves to the retracted position under the bias upon a drop in pressure of fluid delivered by the valve member in either of its positions. The switchover piston and the latch piston have a cooperating recess and detent arrangement for holding the switchover piston in one or the other of its two positions.
Other objects and features of the present invention will be in part apparent and in part pointed out hereinafter.
REFERENCES:
patent: 2440478 (1948-04-01), Kehle
patent: 2626628 (1953-01-01), Norway et al.
patent: 2651491 (1953-09-01), Ashton et al.
patent: 3033220 (1962-05-01), St. Clair
patent: 3464741 (1969-09-01), Falk
patent: 3533431 (1970-10-01), Kuenzel
patent: 4253481 (1981-03-01), Sarlis, Jr.
patent: 4493435 (1985-01-01), Hartley
patent: 4674526 (1987-06-01), Athanassiu
patent: 5014733 (1991-05-01), Wilson
patent: 5127426 (1992-07-01), D'Archambaud
Boyer Robert A.
Pryor David A.
Hepperle Stephen M.
Senniger Powers Leavitt & Roedel
Victor Equipment Company
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