Fluid handling – Line condition change responsive valves – Safety cut-off requiring reset
Reexamination Certificate
2000-10-12
2002-10-08
Walton, George L. (Department: 3753)
Fluid handling
Line condition change responsive valves
Safety cut-off requiring reset
C137S625410, C137S625460, C137S907000, C251S073000
Reexamination Certificate
active
06460564
ABSTRACT:
FIELD OF THE INVENTION
The invention is related generally to shut-off valves for liquid suction systems and, more particularly, to shut-off valves for water suction systems for swimming pools, spas and the like. Still more particularly, this invention relates to rotary-plug shut-off valves for suction cleaning systems for swimming pools, spas and the like.
BACKGROUND OF THE INVENTION
Liquid suction systems are employed in a variety of settings and for a variety of purposes. One example is the liquid suction systems which are used for swimming pools, spas and the like. Such a system typically includes a suction pump away from the pool which draws water from the pool at one or more suction ports located along the pool sidewall and/or through the main drain of the pool. A hose is typically connected to one of the sidewall ports and extends to an automatic swimming pool cleaner which draws pool water for cleaning purposes.
Typically, one or more valve mechanisms are used to determine whether water will be sucked from the pool through the main drain and/or through the side port(s). One example of such valve mechanisms is the three-way rotary-plug valve disclosed in U.S. Pat. No. 4,470,429 (Johnson). Such device is a manually-operated rotary-plug valve.
In swimming pool suction systems, when suction lines become obstructed with debris, damage to the lines and equipment may result if excessive vacuum pressures are not quickly released. Furthermore, a risk of bodily injury may exist if a vacuum or suction device comes into contact with a person. Various bypass devices have been developed to address problems of excessive vacuum due to blockage. One example is the device disclosed in U.S. Pat. No. 4,570,660 (Chauvier). Another is the automatic locking bypass valve which is disclosed in our copending U.S. patent application Ser. No. 09/327,913 (Rief et al.), filed Jun. 8, 1999.
Valve mechanisms of the prior art for controlling which lines will be open to vacuum forces, such as the rotary-plug valve of the aforementioned Johnson patent, have various shortcomings. Among these are the fact that they require manual operation, and thus fail to address problems associated with unexpected line clogging or blockage. Also, even when operated manually such devices fail to provide any vacuum relief in a line which has been manually shut off because of line blockage. In such cases, it may become necessary to turn off the pump and reopen the line in order to relieve the vacuum force remaining in the line. Furthermore, while such devices can be locked into a predetermined position, such locking requires an additional manual step, beyond merely closing a line.
The prior art fails to disclose or suggest a rotary-plug shut-off valve which overcomes these problems and shortcomings.
OBJECTS OF THE INVENTION
It is an object of this invention to provide an improved rotary-plug shut-off valve overcoming some of the problems and shortcomings of the prior art.
Another object of this invention to provide an improved rotary-plug shut-off valve which can operate automatically, i.e., which automatically shuts off a line when vacuum pressure in such line exceeds a predetermined acceptable range of vacuum pressures.
Another object of this invention is to provide an improved rotary-plug shut-off valve which automatically locks in a shut-off position in response to unacceptable line pressures.
Another object of the invention is to provide an improved rotary-plug shut-off valve which automatically relieves the vacuum pressure in a closed line after such line has been shut off.
Yet another object of the invention is to provide a rotary-plug shut-off valve which shuts off a flow line due to unacceptable vacuum pressure therein due to blockage and simultaneously relieves the unacceptable vacuum pressure in the line upon line shut-off.
Another object of the invention is to provide an improved rotary-plug shut-off valve which, although it automatically shuts off a line and automatically relieves line pressure, has a override for manual operation and resetting.
Still another object of the invention is to provide an improved automatic rotary-plug shut-off valve mechanism which can be used to retrofit a standard rotary-plug shut-off valve.
Another object of the invention is to provide an improved rotary-plug shut-off valve which is simple in construction and easily maintained.
These and other objects of the invention will be apparent from the following descriptions and from the drawings.
SUMMARY OF THE INVENTION
This invention is an improved shut-off valve for use in liquid suction systems. More specifically, this invention is an improved rotary-plug shut-off valve of the type including a multi-port valve body forming a valve chamber and having an outlet and first and second inlets, a rotary plug in the valve chamber, and an actuator to turn the plug. The improvement of this invention overcomes the aforementioned problems and shortcomings of the prior art; it is an improved shut-off valve which satisfies the objects of the invention set forth above.
The improved shut-off valve of this invention includes as its principal elements: an actuator housing; a base member; a vacuum-reactive member; a spring; and a piston. The actuator housing is affixed to the valve body adjacent to the plug, and forms an actuator chamber which is in fluid communication with the valve chamber, e.g., through openings in the base member. The base member is affixed to the actuator housing in position to form one end of the actuator chamber. The base member also forms (1) a sleeve through which a portion of the piston extends, (2) a guide which engages a portion of the piston, as hereafter explained, and (3) a first spring-abutment. The vacuum-reactive member is located within the actuator chamber and is movable toward and away from the base member, along the axis of the actuator chamber. The vacuum-reactive member also forms a second spring-abutment which is opposed to the first spring-abutment.
The aforementioned spring is in axial compression and rotational tension between the first and second spring-abutments and is compressible by vacuum force on the vacuum-reactive member. The spring, which is preferably in the form of a coiled helix, serves at the proper time to provide the turning force necessary to move the rotary plug from a position covering one inlet to the valve chamber to a position closing the other inlet to the valve chamber. As hereafter explained, the spring moves the rotary plug by acting through the vacuum-reactive member and the piston.
The piston is affixed to the vacuum-reactive member and is rotationally aligned with the plug. The piston includes a shaft which extends through the sleeve. The piston also includes an anti-rotation structure which is: (a) slidably engaged with the guide (portion of the base member) in one rotational alignment therewith when in a normal operating range of axial positions with respect thereto—i.e., when the piston anti-rotation structure and the guide (of the base member) are within a normal operating range of relative axial positions; and (b) out of sliding engagement with the guide beyond such normal operating range of relative axial positions—i.e., when the piston anti-rotation structure and the guide (of the base member) are within a normal operating range of relative axial positions.
Given these parts and relationships, when the anti-rotation structure of the piston is out of sliding engagement with the guide, and thus free to rotate, the spring rotates the vacuum-reactive member and piston. This rotation of the piston causes the plug to rotate, under the uncoiling pressure of the spring, from one inlet to the other inlet.
In highly preferred embodiments, the first and second inlets are at the ends of first and second inlet lines extending to the valve chamber, and a vacuum-relief line extends from one of the inlet lines, at a position upstream of the valve chamber, to atmosphere and a vacuum-relief valve is located in such vacuum-relief line. It is highly preferred in such embodiments to have link
Rief Dieter J.
Schlitzer Hans
Jansson & Shupe & Munger Ltd.
Walton George L.
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