Pipes and tubular conduits – With closures and plugs
Reexamination Certificate
1999-10-06
2001-01-09
Brinson, Patrick (Department: 3752)
Pipes and tubular conduits
With closures and plugs
C138S090000, C073S049800
Reexamination Certificate
active
06170530
ABSTRACT:
BACKGROUND
The present invention relates to pipe sealing devices and more particularly, relates to an improved sealing device for the temporary sealing of pipe ends and a method of installation of such device. Although the invention will be described in respect of its application to plumbing pipes it will be appreciated by those skilled in the art that the invention may be applied to piping in other fields.
PRIOR ART
There are numerous devices in the marketplace which are used for temporary and permanent sealing of fluid bearing pipes. Broadly these can be divided into two categories. The first comprises end covers or dust caps which are placed over the ends of pipes to prevent ingress of foreign particles and which have no pressure resistant capabilities. The second category of devices are those which have the capacity to seal pipes bearing pressurised fluids and these generally comprise pneumatic or mechanical devices with the former relying on air pressure to urge a resilient deformable member against the walls or end of a pipe to thereby effect sealing. Another example of sealing devices is a solenoid wherein a plastics material actuated electrically, mechanically engages the end of a pipe thereby effecting the seal, even where the pipe bears a pressurised fluid.
U.S. Pat. No. 3,704,729 for example which falls in the second category above discloses a plumbing device for plugging a pipe including a radially expansible rubber sleeve disposed about an end of an axial shaft or tube. Devices such as this rely on the establishment of a frictional engagement between the expansible rubber sleeve and the internal surface of a pipe to be sealed. However reliance on frictional engagement has the limitation that resistance to blow out is totally reliant on the co-efficient of friction established.
An alternative device for closure of a pipe end falling in the first category is disclosed in U.S. Pat. No. 4,046,168. The plug disclosed in that patent comprises a circular disc portion and an annular skirt projecting from the periphery of the disc portion to one side thereof and a pipe member which projects in the direction of the longitudinal axis of the plug from the centre of the disc portion to one side. This device relies for its engagement and therefore sealing of the pipe on an annular skirt to engage the internal surface of the pipe to be sealed and an abutment member which limits entry of the plug to a predetermined distance along the pipe. Plugs of this nature rely heavily on frictional engagement between the material of the plug and the inner surface of the pipe to be sealed and are also prone to popping out where the pressure in the pipe exceeds the capability of the plug to withstand such pressure even though this is likely to occur at a lower pressure threshold. Plumbers are frequently engaged in installations which require temporary termination of the water service and restoration of the service at the end of the day to prevent interruption to the supply where the work temporarily ceases. Where there is partially completed pipe work the pipe ends must be temporarily sealed (sometimes only overnight until work recommences the next day) necessitating preparation of a seal that will withstand normal operating pressures.
According to prior art methodology, pipes may be sealed temporarily by firstly heating the pipe end with Oxy and Acetylene, squeezing or crimping the heated end closed, followed by brazing the pipe end with silver solder to ensure a sound joint. Another method was to weld on to the end of a cut pipe a preformed thread followed by screwing on a threaded cap or valve.
In pipe reticulation networks the tradesman usually leaves testing the pipes until completion due to the time consuming and thus costly methods of sealing mentioned above. This can result in some networks not being fully and properly tested due to possible rendering over as building work progresses. If leaks are later detected the builder or tradesman must incur the cost of making good the defect. Also, there is a wastage factor in adopting the crimping and brazing method which adds to the cost of piping. This arises from crimping of the pipe which effectively damages a length of pipe which must be later cut off. Plumbers usually cut off the crimped end to restore the open pipe end which causes loss of anywhere between 100-200 mm of pipe depending upon the distance from the crimp the plumber chooses to make the cut.
The present invention seeks to provide a simple alternative to the above sealing methods and devices, and more particularly provides a removable plug and method of insertion thereof for conveniently sealing a pipe without complete reliance on friction between the plug and inner walls of a pipe to be sealed and which precludes the need to temporarily seal a fluid bearing pressure pipe by crimping and welding leading to pipe wastage.
INVENTION
In one broad form the present invention comprises;
a releasable plug for temporarily sealing an open end of a fluid bearing pipe having at its open end an inwardly directed flange formed upon cutting said pipe; said plug comprising;
an elongated shaft including at a first end a threaded region and at a second end a collar;
a sleeve surrounding said elongated shaft and including at one end a collett and at a second end an abutment surface wherein sealing means are provided between said abutment surface and said collar;
and wherein, the sleeve further comprises a recess at or near said collett which receives said flange thereby providing resistance against unwanted release of said plug from said open end of said pipe.
According to a preferred embodiment the sleeve is deformable to allow passage of the plug through the space defined by said annular flange and to allow said annular flange to engage said recess.
Preferably the threaded region receives a nut which when rotated in a first direction engages a surface of the collett urging the sleeve towards the collar on said shaft so that said sealing means is compressed between said sleeve and said collar causing frictional engagement between the plug and an inner surface of the pipe. Preferably the sealing means is a rubber O-ring.
In another broad form the present invention comnprises;
a removable plug for temporarily sealing an open end of a fluid bearing pipe or tube including a flange formed at the mouth of said open end and which projects radially inwards from an inner surface of said pipe or tube; the plug comprising;
a deformable body having disposed peripherally thereabout a recess or groove which when said plug is inserted in said opening receives said flange such that at least one wall of said recess or groove engages either one or both surfaces of the flange and/or the inner surface of the pipe to effect sealing between the plug and pipe.
In its broadest form the present invention comprises;
a releasable plug for sealing an open end of a fluid bearing pipe having at its open end an inwardly directed flange formed upon cutting an end of said pipe; said plug including a plug body, an annular recess formed in the body which engages said flange, and a seal or a sealing device which frictionally engages an inner surface of said pipe thereby providing a pressure seal for said pipe.
According to one embodiment the plug comprises a generally disc shaped body with the recess formed by a bifurcation in the body near the circumferential region said bifurcation terminating in two resiliently deformable wall members such that the disc is generally H shaped in cross section.
The flange on the pipe or tube is formed preferably by means of a roller cutter which enables the formation of a consistent inwardly directed flange of sufficient strength to withstand fluid pressures which will be generated on the plug. The flange width may fall within the range 0.1 mm to 3.0 mm.
According to one embodiment in order to effect sealing of the pipe the outer extremity of the wall of the groove upstream of the flange will frictionally engage the inner surface of the pipe and/or engage the flange. However, unlike the known s
Brinson Patrick
Hollander Law Firm, P.L.C.
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