The present invention relates to a valve assembly that is easily connected to and disconnected from lateral sections of irrigation pipe connected to a water supply.
Irrigation systems require valves to be connected to and disconnected from lateral sections of irrigation pipes that are in turn connected to a supply of water. Prior art irrigation valves are connected by threading them onto pipe sections using a sealant such as Teflon tape to prevent leakage. The pipe sections and valves are typically plastic such as polyvinyl chloride (PVC). However, because of the nature of the plastic materials used to manufacture the irrigation pipe sections and valves and the environmental conditions of temperature and pressure, the joints between the valves and the sections leak even when they are thoroughly tightened.
It is well known in the prior art to provide union fittings for the valves to create male threaded extensions. The union fitting in the prior art typically has one of the male threaded ends for being screwed into each of the threaded openings of the valve. The other male threaded end is capable of being screwed into a nut positioned behind a flange attached to a section of pipe to be connected. The problem with such union fittings is that they suffer from the same disadvantage as conventional connections of the male fittings on the inlet and outlet ports of the valve. In such prior art fittings, the entire valve must still be rotated to unthread the valve and remove it from the union fittings.
Irrigation systems require a network of pipe sections to be connected to valves that lay on the ground in close proximity to one another on a manifold. Because the prior art valves having internally (female) threaded openings are threaded onto the male threaded ends of the pipe sections as discussed in the above paragraph, sufficient clearance must be provided to allow rotation of the valve around its axis during threading and unthreading of the valve. Often in such prior art systems, the lateral spacing between the valves and the pipe sections must be increased to provide sufficient clearance. Another problem with the prior art irrigation systems is the failure to provide an adequate seal between the valve and pipe sections.
There is a need for an irrigation valve assembly that can be easily connected and disconnected while maintaining the same spacing between the lateral sections that are being connected to the inlet and outlet ports of the valve assembly and one that does not require having to move the sections. There is also a need for an assembly that does not require the rotation of the entire assembly onto the male threads of the pipe. There is also a need for a valve assembly that prevents leaks between the valve ports and the threaded connections.
The foregoing aspects and the attendant advantages of the present invention will become more readily appreciated by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
Referring now to
Connector sub-assembly 8 includes a pair of swivel connectors 30 capable of freely rotating around longitudinal axis 28. Preferably swivel connector 30 is a plastic threaded fitting, which has female threaded end 32 for connecting to the male threaded ends of sections 34 of an irrigation pipe. Unthreaded end 36 of connector 30 has shoulder 38, which has outwardly directing end 39 that is substantially perpendicular to axis 28 of control valve 10. The corresponding inwardly directing end of shoulder 38 is the inner corner of unthreaded end 36. Inner surface 40 of shoulder 38 extends between unthreaded end 36 and outwardly directing end 39 and is adjacent to outer surface 42 of each of ports 12 and 14.
Sufficient clearance 44 is maintained between inner surface 40 and outer surface 42 to allow connectors 30 to freely rotate about axis 28 and to allow freedom for lateral movement along axis 28 before the male threads 48 of pipe sections 34 engage the female threads 50 of connectors 30. Sufficient clearance must also be allowed between male threads 48 and threads 50 to assure easy engagement of pipe section 34 even if there are variations in the size of the mating pipe threads. Connector 30 must be able to be screwed all the way onto the pipe threads 48 without licking on the taper of the mating threads.
Control valve 10 can also be easily removed from sections 34 without appreciable lateral movement of the sections by loosening connectors 30 and sliding them inwardly until ends 36 are adjacent ends 54.
The height of shoulder 26 is the distance inwardly directing end 27 is from outer surface 42 of ports 12 and 14. The thickness of shoulder 38 is the distance outwardly directing end 39 of shoulder 38 extends above threads 50. On the one hand, these distances should be large enough to prevent connector 30 from being removed from control valve 10 during the rigorous field operations. On the other hand, these distances should be small enough to enable the shoulder 38 on connector 30 to be forced over shoulder 26 of ports 12 and 14. Once connectors 30 are in place they must permanently attached to valve assembly 10. The height of shoulder 26 and thickness of shoulder 38 are substantial equal and range from about 1/16 to ⅓ the thickness of inwardly directing end 36, which is the distance from inner surface 40 to outer surface 56 of connector 30.
In a specific example of a PVC valve assembly 10, connector 30 had a thickness of end 36 of 0.4 inch for threading fully onto any standard 1 inch male NPT (National Pipe Taper) or BSP (British Standard Pipe) fitting. Connector 30 was permanently attached to the valve inlet port 12 and outlet port 14 by compressing shoulder 38 of connector 30 over a tapered metal mandrel to a fraction of the thickness of outwardly directing end 39. Shoulder 38 was compressed within the range of about 0.04 to about 0.08 inch. Immediately after being compressed, connector 30 was removed from the tapered mandrel and was easily forced over shoulder 26. Shoulder 38 was then allowed sufficient time to resume substantially its original shape based on well known principles of plastic hysteresis.
Various modifications of the control valve assembly of the present invention in addition to those shown and described above will become apparent to those skilled in the art from the foregoing description and accompanying drawings. Such modifications are intended to fall within the scope of the appended claims.