Pipe coupling capsulation assembly

A pipe coupling capsulation assembly includes a band having an inner annular seal element wrappable around a pipe, opposing clamp members that extend from the band, and one or more tightening elements for clamping together the clamp members. Retaining elements are assembled to the annular seal element.

FIELD OF THE INVENTION

The present invention relates generally to pipe coupling assemblies, such as those used to sealingly connect pipes together or to repair breaks or leaks in pipes, and particularly for pipe coupling capsulation applications in which the pipe coupling fits over existing bell-shaped joints and sleeve joints and seals the joint.

BACKGROUND OF THE INVENTION

Many kinds of removable band-type couplings for pipes exist in the art. It is noted that throughout the specification and claims, the term “pipe” encompasses any kind of generally cylindrical object, and the terms “clamp” and “coupling” are used interchangeably.

Pipeline leakage must be prevented for both economic and environmental reasons, depending on the nature of the fluid being transported. When needed repairs are inevitably carried out under field conditions, and in many situations there is a requirement that the flow of fluid in the pipeline may not be interrupted for any reason. Thus replacement of a faulty pipe joint is not an option.

Prior art seals are not capable of being used externally over an existing coupling or existing bell joint. Prior art seals lack the internal space needed if the repair seal is to be applied over and around an existing but leaking pipe joint. A further problem with many prior-art seals arises when the fluid being transported is under high pressure. This results in the seal lips being gradually pushed outwards, eventually leading to complete seal failure.

A solution to the above problems is described in Israel Patent 196511, assigned to Krausz Industries Ltd. This patent describes an external seal completely enveloping the existing leaking seal. This is referred to as a capsulation assembly. The capsulation seal assembly fits over existing bell-shaped joints, sleeve joints and the like, and seals the joint. The assembly is briefly described with reference toFIGS. 1-5.

FIG. 1illustrates an existing bell joint coupling1that couples two pipes2and3. A capsulation assembly4includes a seal5with an internal cavity6that is sized to fit over the bell joint1, without having to disturb the bell joint1. The seal5is tightened by clamp members7(with tightening fasteners, not shown).

FIG. 2illustrates an existing sleeve joint coupling8after repair by capsulation assembly4. As before, internal cavity6is sized to fit over the sleeve joint8.

FIG. 3illustrates the profile of seal5, which has an outer substantially rectangular shape with surfaces5A and internal cavity6. Spaced-apart, circumferential passageways9are each formed through a portion of a seal lip10. Axial passageways11, transverse to circumferential passageways9, are formed in seal lips10and form a hydraulic connection between circumferential passageways9and internal cavity6. The hydraulic pressure within internal cavity6applies additional hydraulic pressure on seal lips10by means of fluid flowing through the passageways and pressing the lip10further against a pipe (not shown).

Seal lips10have seal surfaces12formed with ridges13, which contact the pipes2and3inFIGS. 1 and 2. The ridges13provide clearance for surface irregularities and for small solid particles which may be entrained in the fluid flowing through the pipes.

InFIG. 4, the seal5is formed with surfaces14and15that slope inwards from bottom surface16. InFIG. 5, an additional circumferential passageway17is formed through a portion of seal lip10.

However, a problem of the prior art assembly can occur after tightening clamp7. The tightening applies pressure to seal5and can cause portions of seal5to escape or migrate partly out of the clamp.

SUMMARY OF THE INVENTION

The present invention seeks to provide an improved pipe coupling capsulation assembly, as is described more in detail further below. In the present invention, the seal is provided with segmented retaining elements that prevent migration of the seal from the coupling housing.

There is provided in accordance with an embodiment of the present invention a pipe coupling capsulation assembly including a band having an inner annular seal element wrappable around a pipe, opposing clamp members that extend from the band and which are formed with mounting holes, at least one tightening element for clamping together the clamp members, the tightening element passing through the mounting holes, and a plurality of retaining elements assembled to the annular seal element.

In accordance with an embodiment of the present invention the retaining elements are received in slots formed in the annular seal element.

In accordance with an embodiment of the present invention each of the retaining elements includes a mounting portion that is received in a slot formed in the annular seal element.

In accordance with an embodiment of the present invention each of the retaining elements includes a retaining flap arranged to block outward migration of the annular seal element.

In accordance with an embodiment of the present invention each of the retaining elements includes a cap portion that extends axially across at least part of or all of a length of the annular seal element and extends a circumferential segment of a circumference of the annular seal element.

In accordance with an embodiment of the present invention a mounting portion extends from the cap portion and extends radially inwards, and is received in a radial slot formed in the annular seal element.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Reference is now made toFIGS. 6 and 7, which illustrate a pipe coupling capsulation assembly20, constructed and operative in accordance with a non-limiting embodiment of the present invention.

Assembly20includes a band22having an inner annular seal element24wrappable around a pipe (not shown). Band22is typically, but not necessarily, made of metal and annular seal element24is typically, but not necessarily, made of an elastomer, such as natural or synthetic rubber. Annular seal element24is similar to the abovementioned prior art seal5but with important structural differences as will be explained below.

Opposing clamp members26extend radially outwards from ends of band22and are formed with mounting apertures28. Clamp member26are clamped and tightened together with one or more tightening elements30, such as but not limited to, bolts that pass through a bolt plate31, and which are tightened by nuts32(with optional washers33) at a nut plate34.

In the illustrated embodiment, band22and annular seal element24are constructed of two opposing halves and thus there are two pairs of clamp members26(top and bottom in the illustration). However, the invention can be carried out with one pair of clamp members26, wherein band22and annular seal element24are split only once and are not two halves.

In accordance with a non-limiting embodiment of the present invention, a plurality of retaining elements40are assembled to annular seal element24. The retaining elements40may be made of stainless steel or other suitably strong material. In the illustrated embodiment, each retaining element40includes a cap portion42that extends axially across at least part of or all of the length of seal element24and which subtends a circumferential segment of the circumference of seal element24. A mounting portion44extends from cap portion42and extends radially inwards. Mounting portion44is received in radial slots46formed in annular seal element24. A retaining flap48extends from mounting portion44(or from cap portion42) and extends radially inwards. Retaining flap48blocks any outward migration of annular seal element24. If desired, one or more of the retaining elements40may be fastened to band22by fasteners43through apertures41formed in retaining elements40. Retaining elements40may be made by bending or other suitable method.

Radial slots46have the additional function of making the seal more flexible so it is much easier to give the seal its annular shape for assembly.

For additional resistance against outward migration of annular seal element24, a retaining wire50may be mounted through apertures52and54formed in retaining elements40and annular seal element24, respectively. The ends of the wires50may be joined to each other or to some other structure in the assembly, if need be, such as by fastening, twisting, soldering, bonding, etc.