Pipe repair clamp

Details Pipe repair clamp Pipe repair clamp

1999-01-25

2001-10-23

Nicholson, Eric K. (Department: 3627)

Pipe joints or couplings

Repair

C285S285100, C285S294100, C285S294300, C285S373000, C285S296100, C138S099000

Reexamination Certificate

active

06305719

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a clamp for repairing a damaged pipe member, and more particularly to an improved technique for forming a seal between a replaceable insert and a shell or housing for the insert around the damaged pipe member.
BACKGROUND OF THE INVENTION
Leak repair clamps typically bolt or are otherwise fastened around a leaking pipe, flange or valve as a means of repairing the damaged pipe member and stopping fluid leaking therefrom. Such clamps typically have a housing that goes around the damaged pipe member, and a seal at either end thereof. A liquid sealant is usually injected into an annular cavity formed between the housing of the repair clamp, the outside surface of the pipe member, and the seals at either end. The liquid sealant cures to form a seal along the entire length of the annulus.
It is sometimes undesirable to fill the entire annulus with liquid sealant. The sealant is relatively expensive, and can create problems if the leak repair member needs to be removed or replaced. The presence of the liquid sealant in the annulus can also create problems when it is desired to service the pipe member.
In some types of leak repair clamps, the seals at either end are provided as replaceable inserts. See, for example, French Patent 2,426,852; and U.S. Pat. No. 5,118,139 to Lott. These inserts can facilitate manufacturing the inserts and housings or shells in different operations. However, the use of separate inserts and housings requires that a seal be formed between the insert and the housing, in addition to the seal between the inserts and the pipe member. This seal between the inserts and the housing is typically metal-to-metal which requires close machining tolerances, or in some cases the inserts are welded to the housing. The welding, of course, creates another process step in the fabrication or installation of the repair clamp.
SUMMARY OF THE INVENTION
The present invention uses segmented inserts to form a ring assembly inside an outer shell to support a seal against a damaged pipe member. An annular channel is formed between the outer shell and the ring assembly. Liquid sealant can be injected into the annular channel to form a seal between the insert and the shell. A liquid sealant-receiving channel can also be formed between first and second seals of the ring assembly to make a better seal between the ring assembly and the pipe member. Similarly, longitudinal liquid sealant-receiving channels can be formed between opposing longitudinal faces of the shell members that make up the shell between a pair of ring assemblies disposed at either end of the shell to seal the shell between the ring assemblies up to the annular channel between the outer shell and the ring assemblies. In this manner one can avoid the need to fill the entire annular cavity between the shell and the pipe member between the ring assemblies. The liquid-sealant seal between the ring assembly and the outer shell can avoid the need for a metal-to-metal seal, or serve as further seal in addition to a metal-to-metal seal, and eliminate welding the insert segments to the shell members. The manufacture and installation of the leak repair clamp is thus facilitated by the present invention.
Accordingly, in one aspect, the present invention provides a clamp for repairing a damaged pipe member. The clamp has a pair of shell members with opposing longitudinal faces matingly engageable around the damaged pipe member, preferably to form longitudinal seals on opposite sides of the damaged pipe member. Segmented inserts are received in a complementary annular channel formed in an inside face of the shell members to form a ring assembly supporting at least one annular seal between the ring assembly and the damaged pipe member. A shell-sealing annular channel is formed between the ring assembly and the shell members for receiving a liquid sealant to form an annular seal between the ring assembly and the shell members. Means are provided for drawing the shell members together in mating engagement to form a shell assembly around the damaged pipe member. Sealant injection fittings or valves can also be provided for injecting the liquid sealant into the shell assembly.
The shell members preferably have a longitudinal channel formed in the matingly engaged longitudinal faces, between a pair of ring assemblies at either end of the shell members, for receiving liquid sealant to facilitate forming the longitudinal seals. The longitudinal channel is preferably in fluid communication with the shell-sealing annular channels adjacent each of the ring assemblies to form a continuous liquid sealant-filled channel between the shell members, and between the shell assembly and the ring assemblies. The shell members preferably have opposing longitudinal flanges which can be bolted or otherwise drawn together to form the housing around the damaged pipe member. The longitudinal seals are preferably formed in the longitudinal faces of one shell member, while the opposing longitudinal faces of the other shell member are preferably smooth.
Each ring assembly can support a seal against the damaged pipe member which includes longitudinally spaced-apart inner and outer annular seals between each ring assembly and the damaged pipe member. The annular seals can be formed with crush rings, crunch teeth or the like. In this embodiment, the clamp preferably also includes a pipe-sealing annular channel formed between each ring assembly and the damaged pipe member between the inner and outer annular seals for receiving a liquid sealant. Each pipe-sealing annular channel is preferably in fluid communication with a respective shell-sealing annular channel.
Bores can be formed through one or both of the shell members and at least one of the segmented inserts for injecting a liquid sealant into the shell-sealing and pipe-sealing annular channels. These bores can be aligned.
The inserts preferably have a trailing tongue for interengagement with a complementary groove on an inner edge of the channels formed in the inside faces of the shell members.
In one embodiment, a shell assembly with a single ring assembly is used to seal a leaking flanged connection of a damaged pipe member. The ring assembly supports annular seals against each respective flange of the flanged connection. An annulus is preferably formed along an inner face of the ring assembly adjacent to a gap between the annular seals, i.e. between the flanges of the leaking pipe member. The annulus is preferably in fluid communication with the shell-sealing annular channel for receiving a liquid sealant.
In another embodiment, the present invention provides a clamp for repairing a damaged pipe member which is made of two or more pairs of shell members, each having opposing longitudinally flanged faces matingly engagable to form a plurality of longitudinally spaced shell assemblies along the damaged pipe member, including a pair of end shell assemblies at opposite ends. Segmented joining inserts are received in respect of complementary annular channels formed in inside faces of adjacent shell members at opposing ends thereof to form longitudinally formed ring assemblies joining the adjacent pairs of shell members together. Segmented sealing inserts are received in complementary annular channels formed in inside faces of the end shell assemblies to form a pair of end ring assemblies supporting annular seals between each end ring assembly and the damaged pipe member. A shell-sealing annular channel is formed between each segmented insert and its respective annular channel formed in the shell assemblies. A longitudinal channel is formed at the longitudinally flanged faces of the shell members in fluid communication with the shell-sealing channels at either end of each respective shell assembly. The apparatus further includes means for drawing the flanges of the shell members together to form the shell assemblies. The repair clamp can also include a pipe-sealing annular channel formed between each end ring assembly and the damaged pipe member between the in

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