GB2594239A

GB2594239A - Pipe repair

Info

Publication number: GB2594239A
Application number: GB2004807.0A
Authority: GB
Inventors: David Wild Michael
Original assignee: MW Polymer Products Ltd
Current assignee: MW Polymer Products Ltd
Priority date: 2020-04-01
Filing date: 2020-04-01
Publication date: 2021-10-27
Anticipated expiration: 2040-04-01
Also published as: GB2594239B; GB202004807D0

Abstract

An apparatus for repairing a leak in a damaged portion of a pipe (e.g. polyethylene pipe), comprising: a flexible pad 100 configured to adhere to the damaged portion of the pipe around the leak, in order to cover the leak; a binder (e.g. nitrile rubber tape) for wrapping around the pad and the pipe to further secure the pad against the pipe; and a curable composition (e.g. curable by an exothermic reaction) for application onto the binder once wrapped around the pad and the pipe. The pad may comprise a first layer 112 and a second layer 114. The second layer may be harder than the first layer. The first layer and the second layer may comprise polyurethane. The pad may be formable from a first mixture and a second mixture, wherein each mixture may be curable to form the respective first layer and second layer of the pad. The first and second mixtures may each comprise: a polyol; and an isocyanate, and the second mixture may comprise a greater volume percentage of the isocyanate relative to the first mixture, and a lower volume percentage of the polyol relative to the first mixture. The curable composition may be polyurethane resin.

Description

TITLE

Pipe repair

TECHNOLOGICAL FIELD

Embodiments of the present disclosure relate to pipe repair. Some relate an apparatus for repairing polyethylene piping.

BACKGROUND

The repair of polyethylene pipes used for transporting liquids and gases often requires special tools and techniques, such as tee connections and the temporary duplication of pipe systems. This equipment is expensive, and specialised training is required to carry out the repair. If this repair is carried out with the liquid or gas flowing in the pipe, this involves the insertion of special inflatable spheres through holes drilled in the pipe to stem the flow through the damaged portion of pipe.

Furthermore, this temporary duplication of the pipe system applies a significant load to the pipe, thereby weakening the pipe and increasing the risk of further damage.

BRIEF SUMMARY

According to various, but not necessarily all, embodiments there is provided an apparatus for repairing a leak in a damaged portion of a pipe, comprising: a flexible pad configured to adhere to the damaged portion of the pipe around the leak, in order to cover the leak; a binder for wrapping around the pad and the pipe to further secure the pad against the pipe; and a curable composition for application onto the binder once wrapped around the pad and the pipe.

The pad may comprise a first layer and a second layer. The second layer may be harder than the first layer. The first layer and the second layer may comprise polyurethane.

The pad may be formable from a first mixture and a second mixture, wherein each mixture may be curable to form the respective first layer and second layer of the pad. The first and second mixtures may each comprise: a polyol; and an isocyanate, and the second mixture may comprise a greater volume percentage of the isocyanate relative to the first mixture, and a lower volume percentage of the polyol relative to the first mixture.

The first mixture may comprise 43 % to 53 % by volume of polyol. The first mixture may comprise 47 % to 57 % by volume of isocyanate.

The second mixture may comprise 31 % to 41 % by volume of polyol. The second mixture may comprise 59 % to 69 % by volume of isocyanate.

The first mixture may comprise 46 % to 50 % by volume of polyol. The first mixture may comprise 50 % to 54 % by volume of isocyanate.

The second mixture may comprise 34 % to 38 % by volume of polyol. The second mixture may comprise 62 % to 66 % by volume of isocyanate.

The polyol may be a polyoxyalkylene tria The isocyanate may be methylene diphenyl diisocyanate.

The pad may be substantially rectangular.

The outer face of the first layer may include a projection for insertion into a joint between the pipe and another object, in order to provide a seal.

The curable composition may be curable by an exothermic reaction. The curable composition may be a polyurethane resin.

The binder may be configured to shrink under the application of heat. The binder may comprise a tape, which may be a nitrile rubber tape.

The apparatus may further comprise a wrap for wrapping around the curable composition. The wrap may be a plastic wrap. The plastic wrap may be a polyurethane film.

According to various, but not necessarily all, embodiments there is provided a first mixture and a second mixture curable to form a respective first layer and second layer of a pad for covering a leak in a damaged portion of pipe, the first and second mixtures each comprising: a polyol; and an isocyanate, wherein the second mixture comprises a greater volume percentage of the isocyanate relative to the first mixture, and a lower volume percentage of the polyol relative to the first mixture.

The polyol may be a polyoxyalkylene trio!. The isocyanate may be methylene diphenyl diisocyanate.

According to various, but not necessarily all, embodiments there is provided a pad produced by curing the first mixture of any of the preceding paragraphs to form a first layer of the pad, and curing the second mixture of any of the preceding paragraphs to form a second layer of the pad.

The pad may be substantially rectangular.

The outer face of the first layer may include a projection for insertion into a joint between a pipe and another object, in order to provide a seal.

According to various, but not necessarily all, embodiments there is provided a method for repairing a leak in a damaged portion of a pipe, the method comprising: covering the leak in the pipe using a flexible pad, which is configured to adhere to the damaged portion of the pipe around the leak, in order to cover the leak; wrapping a binder around the pad and the pipe to further secure the pad against the pipe; and applying a curable composition around the binder once the binder is wrapped around the pad and the pipe.

According to various, but not necessarily all, embodiments there is provided a pad including a first layer and a second layer, wherein each layer comprises a polymeric material.

The second layer may be harder than the first layer. The polymeric material may comprise polyurethane.

The first layer may be adhesive.

According to various, but not necessarily all, embodiments there is provided examples as claimed in the appended claims.

BRIEF DESCRIPTION

Some examples will now be described with reference to the accompanying drawings in which: FIG. 1 is a perspective view of a first example pad of the apparatus described herein; FIG. 2 is a side view of the first example pad; and FIG. 3 is a side view of a second example pad of the apparatus described herein.

DETAILED DESCRIPTION

Figs. 1 and 2 illustrate a first pad 100 according to the disclosure, the pad 100 being for covering a leak in a damaged portion of pipe, such as a polyethylene gas pipe. The leak could for instance be a hole or a tear in the pipe. The first pad 100 is flexible, and is configured to adhere to a surface of the damaged portion of the pipe around the leak, in order to cover the leak. In some embodiments, the pad may be substantially rectangular or substantially circular. In other embodiments, the pad may be shaped to correspond to a particular size or shape of a pipe or pipe fitting.

In the example of Figs. 1 & 2, the first pad 100 includes a first layer 112 and a second layer 114, with the first layer 112 being softer than the second layer 114. The softness/hardness of the respective layers can be determined using for instance a Shore (durometer) hardness test. In some examples, the first and second layer are made from a sheet of polymeric material. Preferably, the polymeric material is polyurethane.

In some examples, the pad 100 has a thickness of between 13 and 38 mm. Preferably, the pad 100 has a thickness of between 15 and 27 mm. Most preferably, the pad has a thickness of 19 mm. The thickness of the pad 100 is the extent of the pad in a direction perpendicular to the face 116 of the first layer 112 of the pad 100.

The first layer 112 of the pad is configured to adhere to the surface of the pipe. In addition, the softness of the first layer 112 enables the first layer 112 to deform to fill grooves and contours on the surface of the pipe when pressure is applied to the pad, thereby providing a tight seal around the leak in the pipe. The harder second layer 114, whilst still being flexible, enables the first pad 100 to resist impacts and protect the seal. The harder second layer therefore provides long term sealing capabilities, conforming to the UK industry standard performance specification of a 50 year life.

A first mixture and a second mixture are curable to form the respective first layer 112 and second layer 114 of the pad 100.

In some examples, the first and second mixtures each comprise a polyol and an isocyanate, and are thus curable to form a polyurethane. In some examples, the second mixture comprises a greater volume percentage of the isocyanate relative to the first mixture, and a lower volume percentage of the polyol relative to the first mixture. The greater relative percentage of the isocyanate in the second mixture provides for a harder second layer 114 when the mixture is cured.

In some examples, the first mixture comprises 43 % to 53 % by volume of polyol and the second mixture comprises 31 % to 41 c/o by volume of polyol. Preferably, the first mixture comprises 46 % to 50 % by volume of polyol and the second mixture comprises 34 % to 38 % by volume of polyol. Most preferably, the first mixture comprises 48 % by volume of polyol and the second mixture comprises 36 % by volume of polyol. In some examples, the polyol is a polyoxyalkylene triol. The polyoxyalkylene triol may have a molecular weight of 4900, a density of 1031 kg/m', and a hydroxyl value of 34.

In some examples, the first mixture comprises 47 % to 57 % by volume of isocyanate and the second mixture comprises 59 % to 69 % by volume of isocyanate. Preferably, the first mixture comprises 50 % to 54 % by volume of isocyanate and the second mixture comprises 62 % to 66 % by volume of isocyanate. Most preferably, the first mixture comprises 52 c/o by volume of isocyanate and the second mixture comprises 64 % by volume of isocyanate. In some examples, the isocyanate is methylene diphenyl diisocyanate (MDI). MDI has a molecular weight of 250.25 and a density of 1180 kg/m'.

To form the first pad 100, the second mixture is poured into a mould. The mould is shaped to correspond to the desired shape for the pad, which could for instance be substantially rectangular or substantially circular. Once the second mixture has cured to form the second layer 114, the first mixture 112 is poured into the mould, which cures to form the first layer 112. The first and second mixtures may be allowed to cure at ambient temperature.

Fig. 3 illustrates a second pad 200, which is similar to the first pad 100, but the first layer 212 of the second pad 200 includes a projection 220, which extends outwardly from the pad 100 in a direction away from the second layer 114. In the example of Fig. 3, the projection is substantially triangular.

The projection 220 is for insertion into a leaking joint at the interface between a first pipe and a further object. The further object could be an adjacent second pipe with a larger diameter than the first pipe. The projection 220 ensures a seal between the pipe and the further object by filling the gap between the pipe and further object.

Pipe repair In some examples, a pad such as the first pad 100 or the second pad 200 is included in an apparatus for repairing a leak in a damaged portion of a pipe. The apparatus includes the pad 100, 200, a binder for wrapping around the pad and the pipe to further secure the pad against the pipe, and a curable composition for application onto the binder once wrapped around the pad and the pipe.

In some examples, the curable composition is curable by an exothermic reaction. In some examples, the curable composition is curable at an ambient temperature, which may rise to 60 °C during the exothermic reaction. The curable composition may be a polyurethane resin.

In some examples, the binder is configured to shrink under the application of heat, such as for instance the heat given off by the curable composition when curing. This ensures that the pad 100, 200 is held more tightly to the pipe by the binder, and therefore provides an improved seal over the damaged section of pipe. Furthermore, a tighter initial binding ensures that the binder stays on the pipe, despite the effects of stress relaxation over time. In some examples, the binder is a tape, which may be a nitrile rubber tape.

The pad 100, 200 has been found to not stretch or deform under the application of heat from the exothermic reaction of the curable composition.

In some examples, the apparatus further comprises a wrap for wrapping around the curable composition once cured. The wrap may be a plastic wrap, which is preferably in the form of a plastic film. Most preferably, the plastic film is a polyurethane film.

In use, the pad 100, 200 is placed on the damaged portion of pipe, with the first layer 112 facing the pipe. The first layer 112 then adheres to the damaged portion of pipe.

Once the pad 100, 200 is placed on the pipe, the binder is then wrapped around the pad 100, 200 and the pipe whilst under tension to secure the pad 100, 200 against the pipe.

The curable composition is then applied around the binder and pad 100, 200 and allowed to cure. VVhere the curable composition cures via an exothermic reaction and where the binder is configured to shrink under the application of heat, the binder shrinks around the pad 100, 200 and the pipe to further secure the pad 100, 200 against the pipe. Once the curable composition has cured, additional impact resistance is provided to protect from, for instance, excavating equipment such as a back hoe digger/excavator bucket when the pipe is buried underground.

In some examples, the wrap is wrapped around the curable composition during curing or after curing, in order to protect the curable composition, and further seal the damaged portion of pipe by compressing the curable composition against the pipe.

Where the wrap is a plastic wrap, the wrap may be wrapped around the curable composition until the plastic wrap "necks". Necking is a deformation where relatively large amounts of strain localize disproportionately in a small region of the wrap. Necking is visibly shown where a region of the plastic wrap begins to appear white, and the cross-sectional area of the region of the wrap decreases.

There is thus described a pad for repairing a leak in a pipe and an apparatus for repairing a leak in a pipe with a number of advantages as detailed above and as follows. The pad and apparatus are simple to apply and require no specialised tools, thereby providing a significant cost saving relative to prior arrangements. The pad and apparatus do not stem the flow or reduce the pressure of the gas or liquid passing through the pipe.

Polyethylene pipes, such as those used in the gas industry, can move due to seasonal ground movement. Prior arrangements utilising rigid iron clamps or steel moulds can therefore put these pipes under strain and cause further damage to the pipe. The pad and apparatus described herein can flex with the pipes whilst maintaining a tight seal. Furthermore, the pad and apparatus are impact resistant according to gas industry standards (British standard LC8).

Although examples have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications to the examples given can be made without departing from the scope of the claims.

Features described in the preceding description may be used in combinations other than the combinations explicitly described above.

Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not.

Although features have been described with reference to certain examples, those features may also be present in other examples whether described or not.

The term 'comprise' is used in this document with an inclusive not an exclusive meaning. That is any reference to X comprising Y indicates that X may comprise only one Y or may comprise more than one Y. If it is intended to use 'comprise' with an exclusive meaning then it will be made clear in the context by referring to "comprising only one" or by using "consisting".

The term 'a' or 'the' is used in this document with an inclusive not an exclusive meaning. That is any reference to X comprising a/the Y indicates that X may comprise only one Y or may comprise more than one Y unless the context clearly indicates the contrary. If it is intended to use 'a' or 'the' with an exclusive meaning then it will be made clear in the context. In some circumstances the use of 'at least one' or 'one or more' may be used to emphasise an inclusive meaning but the absence of these terms should not be taken to infer any exclusive meaning.

The presence of a feature (or combination of features) in a claim is a reference to that feature or (combination of features) itself and also to features that achieve substantially the same technical effect (equivalent features). The equivalent features include, for example, features that are variants and achieve substantially the same result in substantially the same way. The equivalent features include, for example, features that perform substantially the same function, in substantially the same way to achieve substantially the same result.

In this description, reference has been made to various examples using adjectives or adjectival phrases to describe characteristics of the examples. Such a description of a characteristic in relation to an example indicates that the characteristic is present in some examples exactly as described and is present in other examples substantially as described.

Whilst endeavoring in the foregoing specification to draw attention to those features believed to be of importance it should be understood that the applicant may seek protection via the claims in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not emphasis has been placed thereon.

Claims

CLAIMS1. An apparatus for repairing a leak in a damaged portion of a pipe, comprising: a flexible pad configured to adhere to the damaged portion of the pipe around the leak, in order to cover the leak; a binder for wrapping around the pad and the pipe to further secure the pad against the pipe; and a curable composition for application onto the binder once wrapped around the pad and the pipe.
2. An apparatus according to claim 1, wherein the pad comprises a first layer and a second layer, the second layer being harder than the first layer.
3. An apparatus according to claim 1 or 2, wherein the first layer and the second layer of the pad comprise polyurethane.
4. An apparatus according to claim 2 or 3, wherein the pad is formable from a first mixture and a second mixture, each curable to form the respective first layer and second layer of the pad, the first and second mixtures each comprising: a polyol; and an isocyanate, wherein the second mixture comprises a greater volume percentage of the isocyanate relative to the first mixture, and a lower volume percentage of the polyol relative to the first mixture.
5. An apparatus according to claim 4, wherein the first mixture comprises 43 % to 53 % by volume of polyol.
6. An apparatus according to claim 4 or 5, wherein the first mixture comprises 47 30 % to 57 % by volume of isocyanate.
7. An apparatus according to any of claims 4 to 6, wherein the second mixture comprises 31 % to 411% by volume of polyol.
8. An apparatus according to any of claims 4 to 7, wherein the second mixture comprises 59 % to 69 % by volume of isocyanate.
9. An apparatus according to any of claims 4 to 8, wherein the first mixture comprises 46 % to 50 % by volume of polyol.
10. An apparatus according to any of claims 4 to 9, wherein the first mixture comprises 50 % to 54 % by volume of isocyanate.
11. An apparatus according to any of claims 4 to 10, wherein the second mixture comprises 34 % to 38 % by volume of polyol.
12. An apparatus according to any of claims 4 to 11, wherein the second mixture comprises 62 % to 66 % by volume of isocyanate.
13. An apparatus according to any of claims 4 to 12, wherein the polyol is a polyoxyalkylene trio!.
14. An apparatus according to any of claims 4 to 13, wherein the isocyanate is methylene diphenyl diisocyanate.
15. An apparatus according to any of the preceding claims, wherein the curable composition for application onto the binder is curable by an exothermic reaction.
16. An apparatus according to any of the preceding claims, wherein the curable composition for application onto the binder is a polyurethane resin.
17. An apparatus according to any of the preceding claims, wherein the binder is configured to shrink under the application of heat.
18. An apparatus according to any of the preceding claims, wherein the binder comprises a tape.
19. An apparatus according to claim 18, wherein the binder comprises a nitrile rubber tape.
20. An apparatus according to any of the preceding claims, wherein the apparatus further comprises a wrap for wrapping around the curable composition when applied to the binder.
21. An apparatus according to claim 20, wherein the wrap is a plastic wrap.
22. An apparatus according to any of the preceding claims, wherein the pad is substantially rectangular.
23. An apparatus according to any of the preceding claims, wherein the outer face of the first layer of the pad includes a projection for insertion into a joint between the pipe and another object, in order to provide a seal.
24. A method for repairing a leak in a damaged portion of pipe, the method comprising: covering the leak in the pipe using a flexible pad, which is configured to adhere to the damaged portion of pipe around the leak; wrapping a binder around the pad and the pipe to further secure the pad against the pipe; and applying a curable composition around the binder once the binder is wrapped around the pad and the pipe.