GB2119893A

GB2119893A - Improvements in or relating to pipe repair clamps

Info

Publication number: GB2119893A
Application number: GB8312849A
Authority: GB
Inventors: Trevor John Pike; Mark Daniel Bagnall
Original assignee: Victaulic Co PLC
Current assignee: Victaulic Co PLC
Priority date: 1982-05-10
Filing date: 1983-05-10
Publication date: 1983-11-23
Also published as: GB8312849D0; GB2119893B

Abstract

According to the invention there is provided a pipe repair clamp comprising a pipe collar having two generally semi-cylindrical flexible metal portions for location about a pipe to be repaired; connectors 4, 5 for securing together the two collar portions; high tensile strength bridging pieces 9 for linking the two collar portions about the pipe; and a gasket member 6 arranged within the collar for providing a seal between the outside wall of the pipe and the edges of the collar portions. <IMAGE>

Description

SPECIFICATION Improvements in or relating to pipe repair clamps This invention relates to pipe repair clamps.

It is common practice where a pipe, such as a water supply pipe, develops a containable crack or pinhole leakage fault to fit a clamp around the pipe the clamp including sealing means and being adapted to be tightened about the pipe to effect a fluid tight repair to the crack or leakage.

It is an object of the present invention to provide such a pipe repair clamp which can be of sturdy construction and of flexible utility.

According to the invention there is provided a pipe repair clamp comprising a pipe collar having two generally semi-cylindrical flexible metal portions for location about a pipe to be repaired; connectors for securing together the two collar portions; high tensile strength bridging pieces for linking the two collar portions about the pipe; and a gasket member arranged within the collar for providing a seal between the outside wall of the pipe and the edges of the collar portions.

The semi-cylindrical portions may be formed of malleable iron or aluminium or steel for example, and may be cast.

By the expression "malleable iron " as used herein is meant that iron which traditionally is referred to as malleable, and also spheroidal graphite iron commonly known as "ductile iron". Such iron may have an elongation at yield of more than approximately 10%.

The two collar members may be connected together by means of nuts and bolts on each side.

The high tensile strength bridging pieces may be formed of steel connected to or embedded in resilient rubber material (for sealing purposes).

Alternatively the bridging pieces may be formed of high strength plastic material.

The gasket member may be constituted by one or more sheets of resilient material disposed about the pipe between the two clamp collar portions. The sheet or sheets may be provided with tapered edge portions for overlapping at its or their joint(s) about the pipe, or may be provided with castellated edge portions providing for inter-digital overlap at the joint or joints. The sheets may be provided on their inner surface(s) with waffle type corrugation to provide for mat sealing. This may be designed to include characteristics providing a degree of pressure sensitivity so as to improve the sealing property as internal pressure is applied. This could for example be provided by flexible lips to the crests of the waffle corrugation. Alternatively the sheets may be provided with edge sealing ribs.

In order that the invention may be more readily understood one embodiment thereof will now be described by way of example with reference to the accompanying drawing which is an isometric exploded view of one embodiment of a pipe clamp according to the invention.

The clamp comprises two half collars 1 formed at malleable iron and having a nominal internal bore of approximately 196 mm and a wall thickness of approximately 5 mm over the majority of their surfaces.

The half collars 1 are provided on each side with two lugs 2 each having square section apertures 3 by means of which they may be connected to each other, through the intermediary of nuts and bolts 4, 5 so as to encircle a pipe to be repaired.

Each bolt 5 may be provided with an enlarged diameter neck having a partially flattened peripheral portion so that the neck is of 'D' cross section, the flattened portion co-operating with any one of the four flat portions of the associated square section aperture 3 in the respective lug 2 thereby preventing rotation of the bolt 5 within the aperture 3. This arrangement enables the bolt to be located easily in any one of four positions within the aperture.

A gasket in the form of two sheets 6 of synthetic rubber arranged with tapering overlap 7 is adapted to be fitted within the two half collars 1 when they are surrounding the pipe to be repaired. The inner surfaces of the sheets 6 are provided with waffle shaped embossment 8 to aid sealing. A pair of steel bridging pieces 9 are disposed one each side of the half collars 1, to provide continuity of the clamping forces between the half collars. The bridging pieces are recessed within and adhesively secured to the outer surface of the gaskets.

It has been found with the arrangement shown, with the wall thickness provided and with the use of malleable iron, the body of each of the collars is capable of sufficient flexure to accommodate a significant variation in external diameter of pipe to be repaired whilst the arrangement and structure of the lugs 2 enables the correct disposition of interconnecting nuts and bolts between the two half collars.

A circular rib 10 is provided on each half collar 1 such that the half collar may be tapped, in the usual manner with malleable iron, to provide an outlet connection. We have found surprisingly, that such a tapping is possible because of the combined thick nessesofthehalfcollarand pipe wall which are sandwiched together and thus provide sufficient tapping thickness, despite the relatively thin walls used in the half collars.

By way of example we have found that with a clamp of the kind hereinbefore described, it is possible to cover a range of pipes having variations outside of diameters of approximately 10 mm from nominal outside diameters of 93 mm to 240 mm.

By means of the invention as hereinabove described we have found it possible to have a pipe repair clamp of considerable flexibility and therefore ability to cover a relatively wide range of pipe sizes, whilst having inherently high strength necessary to realign broken pipes, being able to accepttappings for outlet connections and also to be able to be subjected to total corrosion resistance treatment.

1. A pipe repair clamp comprising a pipe collar having two generally semi-cylindrical flexible metal portions for location about a pipe to be repaired; connectors for securing together the two collar portions; high tensile strength bridging pieces for

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in or relating to pipe repair clamps This invention relates to pipe repair clamps. It is common practice where a pipe, such as a water supply pipe, develops a containable crack or pinhole leakage fault to fit a clamp around the pipe the clamp including sealing means and being adapted to be tightened about the pipe to effect a fluid tight repair to the crack or leakage. It is an object of the present invention to provide such a pipe repair clamp which can be of sturdy construction and of flexible utility. According to the invention there is provided a pipe repair clamp comprising a pipe collar having two generally semi-cylindrical flexible metal portions for location about a pipe to be repaired; connectors for securing together the two collar portions; high tensile strength bridging pieces for linking the two collar portions about the pipe; and a gasket member arranged within the collar for providing a seal between the outside wall of the pipe and the edges of the collar portions. The semi-cylindrical portions may be formed of malleable iron or aluminium or steel for example, and may be cast. By the expression "malleable iron " as used herein is meant that iron which traditionally is referred to as malleable, and also spheroidal graphite iron commonly known as "ductile iron". Such iron may have an elongation at yield of more than approximately 10%. The two collar members may be connected together by means of nuts and bolts on each side. The high tensile strength bridging pieces may be formed of steel connected to or embedded in resilient rubber material (for sealing purposes). Alternatively the bridging pieces may be formed of high strength plastic material. The gasket member may be constituted by one or more sheets of resilient material disposed about the pipe between the two clamp collar portions. The sheet or sheets may be provided with tapered edge portions for overlapping at its or their joint(s) about the pipe, or may be provided with castellated edge portions providing for inter-digital overlap at the joint or joints. The sheets may be provided on their inner surface(s) with waffle type corrugation to provide for mat sealing. This may be designed to include characteristics providing a degree of pressure sensitivity so as to improve the sealing property as internal pressure is applied. This could for example be provided by flexible lips to the crests of the waffle corrugation. Alternatively the sheets may be provided with edge sealing ribs. In order that the invention may be more readily understood one embodiment thereof will now be described by way of example with reference to the accompanying drawing which is an isometric exploded view of one embodiment of a pipe clamp according to the invention. The clamp comprises two half collars 1 formed at malleable iron and having a nominal internal bore of approximately 196 mm and a wall thickness of approximately 5 mm over the majority of their surfaces. The half collars 1 are provided on each side with two lugs 2 each having square section apertures 3 by means of which they may be connected to each other, through the intermediary of nuts and bolts 4, 5 so as to encircle a pipe to be repaired. Each bolt 5 may be provided with an enlarged diameter neck having a partially flattened peripheral portion so that the neck is of 'D' cross section, the flattened portion co-operating with any one of the four flat portions of the associated square section aperture 3 in the respective lug 2 thereby preventing rotation of the bolt 5 within the aperture 3. This arrangement enables the bolt to be located easily in any one of four positions within the aperture. A gasket in the form of two sheets 6 of synthetic rubber arranged with tapering overlap 7 is adapted to be fitted within the two half collars 1 when they are surrounding the pipe to be repaired. The inner surfaces of the sheets 6 are provided with waffle shaped embossment 8 to aid sealing. A pair of steel bridging pieces 9 are disposed one each side of the half collars 1, to provide continuity of the clamping forces between the half collars. The bridging pieces are recessed within and adhesively secured to the outer surface of the gaskets. It has been found with the arrangement shown, with the wall thickness provided and with the use of malleable iron, the body of each of the collars is capable of sufficient flexure to accommodate a significant variation in external diameter of pipe to be repaired whilst the arrangement and structure of the lugs 2 enables the correct disposition of interconnecting nuts and bolts between the two half collars. A circular rib 10 is provided on each half collar 1 such that the half collar may be tapped, in the usual manner with malleable iron, to provide an outlet connection. We have found surprisingly, that such a tapping is possible because of the combined thick nessesofthehalfcollarand pipe wall which are sandwiched together and thus provide sufficient tapping thickness, despite the relatively thin walls used in the half collars. By way of example we have found that with a clamp of the kind hereinbefore described, it is possible to cover a range of pipes having variations outside of diameters of approximately 10 mm from nominal outside diameters of 93 mm to 240 mm. By means of the invention as hereinabove described we have found it possible to have a pipe repair clamp of considerable flexibility and therefore ability to cover a relatively wide range of pipe sizes, whilst having inherently high strength necessary to realign broken pipes, being able to accepttappings for outlet connections and also to be able to be subjected to total corrosion resistance treatment. CLAIMS

1. A pipe repair clamp comprising a pipe collar having two generally semi-cylindrical flexible metal portions for location about a pipe to be repaired; connectors for securing together the two collar portions; high tensile strength bridging pieces for linking the two collar portions about the pipe; and a gasket member arranged within the collar for providing a seal between the outside wall of the pipe and the edges of the collar portions.

2. A pipe repair clamp according to claim 1 wherein the semi-cylindrical portions are cast from malleable iron.

3. A pipe repair clamp according to claim 1 wherein the semi-cylindrical portions are formed from aluminium or steel.

4. A pipe repair clamp according to claims 2 or 3 wherein the two collar members are connected together by means of nuts and bolts.

5. A pipe repair clamp according to claims 1,2,3 or 4 wherein the bridging pieces are formed of steel connected to or embedded in reilient material.

6. A pipe repair clamp according to any one of the preceding claims wherein the bridging pieces are formed of high strength plastic material.

7. A pipe repair clamp according to any one of the preceding claims wherein the gasket member is formed by one or more sheets of resilient material disposed about the pipe between the two collar portions.

8. A pipe repair clamp according to claim 7 wherein the sheet or sheets is or are provided with tapered edge portions for overlapping at its or their joint or joints about the pipe.

9. A pipe repair clamp according to claim 7 wherein the sheet or sheets has or have castellated edge portions providing for interdigital overlap thereof at its or their joint or joints about the pipe.

10. A pipe repair clamp according to any one of claims 7 to 9 wherein the inner surface of the or each sheet is provided with waffle type corrugation.

11. A pipe repair clamp according to claim 9 wherein the crests of the waffle corrugation are provided with flexible lips.

12. A pipe repair clamp according to any one of claims 7 to 9 wherein sealing ribs are provided at or adjacent the edges of the or each sheet.

13. A pipe repair clamp according to any one of the preceding claims wherein one of the cast portions is adapted for the reception of a tapped pipe connection through the side wall thereof.

14. A pipe repair clamp according to any one of the preceding claims wherein the malleable iron has a tensile strength and elongation, and the csting has a thickness, such as to enable sufficient flexibility in the collars to permit variations in size of up to approximately 10%.

15. A pipe repair clamp substantially as shown in and as hereinbefore described with reference to the accompanying drawings.