Fluid handling – Line condition change responsive valves – Safety cut-off requiring reset
Reexamination Certificate
1999-05-04
2001-03-20
Buiz, Michael (Department: 3753)
Fluid handling
Line condition change responsive valves
Safety cut-off requiring reset
C137S497000, C137S519500, C137S533130
Reexamination Certificate
active
06202678
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to the field of shut-off valves for use in connection with sprinkler irrigation systems.
2. Description of Prior Art
Sprinklers for irrigating recreational playing fields, golf courses, lawns and landscapes are often damaged by animals, accidents, mowers, vehicles, and vandalism. When a sprinkler irrigation system is turned on after such an accident, a considerable stream of water is lost where the sprinkler head or riser was damaged or severed. Since the water is no longer directed to the intended area by the sprinkler nozzles, little to no irrigation benefit is realized in the effected area. The amount of this excess flow can be three or more times the original flow rate through the sprinkler, reducing the overall operating pressure of the zone being irrigated. Therefore, the remaining sprinkler nozzles in the zone are not working with the designed uniformity or efficiency, resulting in uneven and inadequate irrigation. Until the system problem is noticed and repaired, water distributed at the damaged site usually runs off the intended area resulting in great wastage.
Since a great deal of sprinkler irrigation systems are operated automatically by an electric controller, any distribution problem will not likely be observed immediately. Consequently, the irrigation system will most likely continue operating for a number of cycles until physical evidence of a system problem begins to appear, such as the yellowing or wilting of lawns or landscapes.
The prior art solution is to provide a high volume shutoff valve in the irrigation system which will automatically shut down the line experiencing a high flow rate. The prior art discloses various structures for shutting off a valve when the valve encounters unusually high flow. High flow, however, exists not only in the instance of a damaged sprinkler head or severed riser, but also when a irrigation zone with empty lines is first started. This happens often when irrigation zones are free to drain to the lowest point between cycles, causing air to replace the draining water in the lines. Upon start up, pressured water pushes the air in front of it causing the air to both move rapidly at a high flow rate. Since air passes through the nozzles of sprinklers much more freely than liquid, the water advancing behind the air moves through the piping systems at velocities much higher than normal flow rates. Under the prior art, such high pressure of either the air or water, or both, resulting from the start-up of empty lines can trigger the high flow valve to shut off. Obviously, this circumstance is not what shut-off valves were designed for.
Therefore, what is needed is a valve which will shut off only in the case of high flow of water resulting from circumstances such as a damaged or removed sprinkler head or riser, but not when the irrigation system is first being started from empty lines. In other words, what is needed is an irrigation shut-off valve which will not give false shut-offs.
BRIEF SUMMARY OF THE INVENTION
The invention is a valve that shuts off only upon the occurrence of excess flow of liquid or water. More specifically, the valve will maintain an open position during: 1) normal flow of liquid material; 2) high flow of materials in a gaseous state; and 3) high flow of materials in a mixed state of gas and liquid, which is common upon start-up of an irrigation system, for instance. The invention is also a method for shutting off flow of liquid through a conduit only upon the occurrence of excess flow of liquid materials.
In the simplest form, the apparatus is a valve comprising a ball and a ball holder. The ball holder has a circumferential side wall and a floor. An inlet orifice is defined in the floor and at least one or more circumferential apertures are defined in the circumferential side wall. A surface external to the valve is disposed above the ball holder. An outlet orifice is defined in the surface. The outlet orifice has a diameter less than the diameter of the ball so that disposition of the ball into the outlet orifice seals the orifice.
Materials passing through the valve in gaseous state, liquid state, or a mixed state of both liquid and gas, must pass through the ball holder. The present invention in the simplest form does not include a main body, since an external conduit, in which the ball holder is disposed, may serve to restrict all of the materials traveling through the valve to enter the ball holder. Likewise, an outlet orifice must be provided on a surface disposed above the ball and ball holder so that the ball can seal the outlet orifice upon excess flow of liquid. This surface with an outlet orifice defined therein may also be external to the valve. In fact, this surface may be attached to or integral with the conduit in which the ball holder is disposed. Therefore, the invention in its simplest form, does not necessarily include a main body or a seal as part of the ball holder. On the other hand, the preferred embodiment comprises a ball, ball holder, a seal on top of the ball holder with an outlet orifice defined in the seal, and a main body which restricts all materials passing through the valve to flow through the ball holder.
The valve effects a shut-off position only upon excess flow of liquid. When liquid enters the valve through either an external conduit or a main body, the liquid must also enter the ball holder. The liquid enters the ball holder through the circumferential apertures in the circumferential side wall and the inlet orifice in the floor. As liquid enters through the circumferential apertures, the circumferential apertures exert resistance on the liquid causing the liquid to enter through the inlet orifice. The higher the flow of liquid through the circumferential apertures, the greater the resistance which leads to higher flow of liquid through the inlet orifice. The area of the circumferential apertures and the inlet orifice, the diameter, weight and volume of the ball, and the height of the ball holder are all designed in proportion to each other such that a predetermined flow of liquid through the inlet orifice will lift the ball to a predetermined height, this height being the point at which the flow of liquid through the circumferential apertures will carry the ball upwards to seal the outlet orifice.
Therefore, in summary it can be appreciated that the invention is a valve that will shut off only upon excess flow of liquid.
The invention can also be characterized as a method for shutting off excess flow of materials in a liquid state through a conduit comprising the steps of providing a valve with a bottom port, a ball, and a surface with an outlet orifice defined in the surface; disposing the surface with the outlet orifice above the ball; seating the ball inside the valve; passing the materials through the bottom port of the valve; flowing the materials in a gaseous or liquid state or a mixed state of gas and liquid to interact with the ball wherein the interaction between the ball and the materials maintains a first position of the ball; flowing the materials in a liquid state above a predetermined flow rate to interact with the ball wherein the interaction between the ball and the liquid materials displaces the ball to a second position whereby the ball seals the outlet orifice.
The invention now having been briefly summarized, it may be better visualized by turning to the following drawings wherein like elements are referenced by like numerals.
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Agricultural Products, Inc.
Buiz Michael
Dawes Daniel L.
Krishnamurthy Ramesh
Myers Dawes & Andras LLP
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