Pipe joints or couplings – Packed – Plural seals
Reexamination Certificate
2000-04-17
2001-09-11
Browne, Lynne H. (Department: 3627)
Pipe joints or couplings
Packed
Plural seals
C285S924000, C285S918000
Reexamination Certificate
active
06286877
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to improvements in pipe joints or pipe couplings of the type having a pair of axially spaced seals to provide a dual seal interface on a matingly interconnected pair of male and female pipe fittings. More particularly, this invention relates to an improved dual seal pipe coupling or joint wherein the inter-seal space is vented at low pressure to prevent seal distortion or damage upon assembly of the pipe fittings in the presence of an incompressible fluid such as water, but further wherein the dual seals provide a substantially leak-free interface in the presence of higher fluid pressure.
Pipe couplings for fluid handling applications are well known in the art, to include a matingly interfitting pair of typically male and female pipe fittings formed on adjacent ends of a pair of conduit members to form an elongated fluid flow path of a desired size and shape. In this regard, elongated conduits or pipes are commonly used in combination with specialized coupling members, such as sleeves, elbows and tees, to provide a custom-configured pipe network to deliver a selected fluid under pressure in gas or liquid form from one location to another. As one example, a typical irrigation system utilizes an array of elongated conduits or pipes assembled with appropriate elbows and tees and the like for delivering irrigation water from a water supply source to a plurality of individual sprinkler devices which distribute the irrigation water to a target terrain area and associated vegetation.
In many irrigation systems, the elongated conduits and associated coupling members are formed from a suitable plastic material for convenient slip-fit and adhesively secured interconnection. While this assembly technique provides a relatively simple leak-free coupling, subsequent rotation of the interconnected pipe components is prohibited. In some instances, such as the connection of a water supply line to an irrigation sprinkler, a so-called swing joint riser assembly is provided with a riser tube and one or more rotatable swing joints to accommodate post-assembly positional adjustment between the interconnected pipe components for orienting the riser tube and associated sprinkler relative to the surrounding terrain. For such swing joint couplings, threaded pipe fittings are typically employed. However, threaded pipe couplings must be tightly interconnected to prevent fluid leakage. Post-assembly rotational adjustment of the riser tube relative to the water supply line typically sets the threadably interconnected pipe components in a partially loosened condition such that some undesirable water leakage can occur.
To resolve leakage problems, swing joint pipe couplings have been developed with one or more seal rings such as resilient O-ring seals to prevent water leakage between the interfitted male and female pipe fittings. In one common design, the male pipe fitting includes a pair of seal rings seated respectively within a corresponding pair of recessed grooves formed at axially opposed ends of an external thread segment. These seal rings are diametrically sized and axially positioned to slidably and sealingly engage annular seal surfaces formed within a threaded bore of the associated female pipe fitting, when the male pipe fitting is threadably assembled therewith. The pair of seal rings provide a dual seal interface to prevent fluid leakage past the interengaged threads, notwithstanding post-assembly relative rotational adjustment between the interconnected male and female pipe fittings.
The dual seal pipe coupling as described above performs well when the pipe fittings are assembled in a dry environment, with fluid in the form of a compressible gas such as air disposed within the inter-seal space between the pair of seal rings. More particularly, as the pipe fittings are assembled, fluid is trapped within the inter-seal space between the axially spaced seal rings. When the trapped fluid comprises a compressible gas such as air, insufficient fluid pressure is generated within the inter-seal space to cause any significant extrusion type distortion or damage to either seal ring. However, when the trapped fluid is an incompressible liquid such as water, a substantial fluid pressure can be generated within the inter-seal space during assembly of the male and female pipe fittings, wherein this fluid pressure can cause undesirable distortion or damage to the seal rings. The presence of an incompressible liquid such as water within the inter-seal space is particularly likely in irrigation system applications since the pipe couplings are often assembled in-the-field in a wet environment.
The present invention provides an improved rotatably adjustable pipe coupling of the dual seal type, wherein fluid trapped within the interseal space at relatively low pressure during assembly of the pipe fittings is vented to prevent seal ring distortion or damage, but further wherein the dual seals provide a substantially leak-tight interface in the presence of higher fluid pressure during normal system operation.
SUMMARY OF THE INVENTION
In accordance with the invention, an improved dual seal pipe coupling is provided for interconnecting a pair of conduit members in a manner permitting substantially leak-free post-assembly rotational adjustment therebetween. The improved pipe coupling comprises a matingly interfitting pair of male and female pipe fittings formed on adjacent ends of the pair of conduit members, with one of the pipe fittings carrying an axially spaced pair of seal rings for slidably and sealingly engaging the other pipe fitting. At least one of the pair of seal rings is associated with a bypass vent for venting the inter-seal space axially between the seal rings at low pressure conditions during initial assembly of the pipe fittings, to prevent pressure build-up and potential seal ring distortion or damage. In the presence of relatively higher fluid pressure during normal operating conditions, this seal ring resiliently deforms to close the bypass vent and provide a substantially leak-free interface.
In a preferred form, the pipe fittings comprise male and female threaded pipe fittings. The seal rings are seated respectively within a pair of axially spaced-apart recessed grooves formed on one of the pipe fittings, such as on the male pipe fitting at axially opposite sides of an external thread segment formed thereon. These seal rings are respectively positioned for slidably and sealingly engaging annular seal surfaces formed on the other pipe fitting, such as a corresponding pair of annular seal lands formed within a threaded bore of the female pipe fitting at axially opposite sides of an internal thread segment formed therein. At least one of the seal ring grooves incorporates the bypass vent, to include a shallow recessed channel underlying the associated seal ring and extending axially to a smoothly curved and generally arch-shaped relief port formed in a side wall at an outboard or downstream pressure side of the seal ring groove.
Upon initial assembly of the pipe fittings, in the event that an incompressible fluid such as water is trapped at relatively low pressure within the inter-seal space between the pair of seal rings, this fluid can escape through the bypass vent to prevent seal ring distortion or damage. However, when subjected to higher fluid pressure such as during normal operating conditions, the seal ring associated with the bypass vent is pressure responsive for resiliently conforming with and sealing against the smoothly curved relief port to prevent fluid escape.
Other features and advantages of the invention will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.
REFERENCES:
patent: 3348863 (1967-10-01), Rinker
patent: 4627644 (1986-12-01), Ekman
patent: 4707000 (1987-11-01), Torgardh
patent: 5292156 (1994-03-01), Sasa et al.
patent: 5845944 (1998-12-01), Enger et al.
Ensworth Mark M.
Evans David V.
Mendoza Rick
Anthony Manufacturing Corp. Industrial Prod. Div.
Browne Lynne H.
Kelly Bauersfeld Lowry & Kelley LLP
Lugo Carlos
LandOfFree
Dual seal pipe coupling does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Dual seal pipe coupling, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dual seal pipe coupling will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2507510