Fluid leak repair

Abstract

Fluid leak repair kits are described comprising a putty, self-amalgamating tape, and a composite material for use in encompassing the self-amalgamating tape. The composite material comprises a flexible sheet or tape and a matrix component for binding the flexible sheet or tape. The matrix component comprises a resin or water-activated matrix component which, when cured, forms an outer shell.

Claims

1. A method of repairing a fluid leak in a pipe or conduit (10), characterized in that the method comprises: applying a layer of non-curing putty (22) to said pipe or conduit (10) at a location of said leak to seal said leak; wrapping, at tension, a self-amalgamating tape (24) around said layer of non-curing putty (22) to cover said layer of non-curing putty and form a tension wrapped region at said location of said leak; contacting a flexible sheet or tape (30) with either: a resin, or water to activate a water-activated matrix component; and encompassing the self-amalgamating tape (24) with the flexible sheet or tape (30) such that the resin or water-activated matrix component binds with the flexible sheet or tape (30) to form an outer shell with the flexible sheet or tape (30) to substantially surround said tension wrapped region.

2. A method according to claim 1, wherein said self-amalgamating tape (24) is wrapped at full tension, in which its width is 75% or less of its original width; the method optionally further comprising, after wrapping, at tension, said self-amalgamating tape (24) around said layer of putty (22) to create said tension wrapped region, wrapping, at less than full tension, a further layer of said self-amalgamating tape (24) around said tension wrapped region to cover said tension wrapped region.

3. A method according to claim 1, wherein said flexible sheet or tape (30) comprises a woven material or wherein said flexible sheet or tape (30) comprises a fibre glass or carbon fibre material.

4. A method according to claim 1, wherein said flexible sheet or tape (30) is pre-impregnated with said matrix component or a component for forming said matrix component.

5. A method according to claim 4, wherein said component for forming matrix component comprises a polymeric water soluble or water-activated substance.

6. A method according to claim 4, wherein said flexible sheet or tape (30) is pre-impregnated with a polyurethane resin.

7. A method according to claim 4, wherein said matrix component comprises 1,2-propanediol, 2-ethyl-2-(hydroxymethyl), polymer with bis(isocyanatomethyl) benzene.

8. A method according to claim 1, further comprising wrapping a stretch wrap material (32) over the flexible sheet or tape (30) including the matrix component whilst said matrix component cures; and/or wherein said self-amalgamating tape (24) comprises a silicone self-amalgamating tape (24).

9. A method according to claim 1, comprising cutting lengths of said self-amalgamating tape (24) prior to wrapping each said length of self-amalgamating tape, at tension, around said layer of putty (22).

10. A method according to claim 9, wherein said lengths of self-amalgamating tape (24) are cut at an angle of 45°.

11. A method according to claim 1, wherein said non-curing putty (22) is a silicone non-curing putty (22).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1A to 1H and 1J-1L are schematic illustrations of respective steps of a method of gas leak or liquid leak repair according to an exemplary embodiment of the invention; and

(2) FIG. 2 is a schematic illustration of respective steps at the end of a method of gas leak or liquid leak repair according to an exemplary embodiment of the invention, for forming the outer shell or armour around the repair.

DETAILED DESCRIPTION

(3) The kits of the present invention are used to create permanent repairs of fluid leaks in pipes. An example will now be described in which the fluid is natural gas within a sealed domestic or commercial gas supply system.

(4) Thus, in general, a gas leak repair kit according to an exemplary embodiment of the present invention comprises a non-curing silicone putty, a high grade silicone self amalgamating tape (SAT) and woven glass fibre bandage with a water activated binder.

(5) It will be appreciated that, using the kit and method according to this exemplary embodiment of the present invention, a permanent gas leak repair can be effected, quickly, reliably and efficiently, by a single operative. An exemplary method is set out in detail below:

(6) Preparation

(7) 1. When a leak is detected, its source must first be identified. Leak detection solution can be used for this purpose (see FIG. 1A of the drawings), although other methods will be known to a person skilled in the art. Optionally, once the location on the pipe of the leak has bee identified, this can be marked, if necessary. 2. Referring to FIG. 1B of the drawings, next the surface of the pipe 10 at the location of the leak must be properly prepared. Rust and debris can be removed using a wire brush 12—optionally at least 30 cm either side of the leak area—following which, the surface around the circumference of the pipe 10 can be sanded (see FIG. 1C of the drawings) to achieve a smooth finish. 3. Referring now to FIG. 1D of the drawings, the region around the leak must next be cleaned. First, clean water and an atomiser spray bottle 14 can be used to wash away all traces of leak detection solution (if used) and abrasion grit. Then the pipe 10 and surrounding area is dried using a clean rag, for example. 4. Referring to FIG. 1E of the drawings, anywhere that the SAT could touch during the repair process, needs to be clean. Thus, using a plastic sheet 16 and masking tape 18, a region behind the area to be repaired can be covered. Ideally, an operative will subsequently put on powder free gloves to complete the repair process, to ensure that the fusion of the SAT is not reduced by transfer of, for example, dirt, oils, perfumes, nicotine, tar, soap or skin from the operative's hands.
Silicone Putty 5. Next, and referring to FIG. 1F of the drawings, the right shape of putty is prepared. The putty is required to ‘plug’ the gap between the coupling member or joint 20 and the pipe 10, and the right ‘shape’ of putty for this purpose will, therefore, dependent on the size and configuration of the area to be ‘plugged’ thereby. It is envisaged that an operative may have to cut a length of putty 22 length ways, possibly generally in half, to create the right shape for a particular job. 6. Referring to FIG. 1G of the drawings, a number of 20 cm strips 24 of the self-amalgamating tape (SAT) is cut by the operative. The number of strips required for a repair is dependent on the size of the coupling member or joint at which the repair is being made, and a table indicating the number of strips of SAT required for each of a number of standard sized joints, is provided below:

(8) TABLE-US-00001 Joint size (inches) Number of strips of SAT required ¾ 3 1 4 1¼ 5 1½ 6 2 9  Each strip of SAT is cut using a 45° angle, as illustrated in FIG. 1G. 7. Referring to FIG. 1H of the drawings, the putty 22 is used to create a so-called wrapping surface. It is manually pushed and manipulated into the gaps between the joint 26 and the pipe 10 to fill any holes, thread or pitted areas, and should not be built up higher than the joint itself. During this process, the operative covers the thread and creates an incline from the pipe 10 up to the joint 26, by applying pressure and creating a smooth finish by hand.
Self-Amalgamating Tape 8. Next, the required number of strips of SAT are wrapped, one by one, over the putty. Such wrapping should be done at full tension, which occurs when the tension therein is such that the colour lightens and its width is reduced to at least ¾ of its original width. Ideally, when wrapping, all leading and finishing edges of the strips should be fully concealed within the wrap. This is the purpose of cutting the tape strips at a 45° angle: the leading edge thus follows the circumference of the pipe rather than lying parallel to it (as it would if the tape was cut square), as illustrated in FIG. 1J of the drawings. 9. Thus, starting about 25 mm from the end of the thread, the operative places the leading edge of a strip of tape onto the pipe and starts wrapping at full tension, overlapping each layer by 80-90%. For each subsequent tape strip, the leading edge is placed fully over the previously applied layer, and then covered 100% before progressing in the wrapping direction. Once the diameter of the wrapped region is the same as that of the joint 26, the operative continues wrapping over the edge, as shown in FIG. 1K of the drawings, wrapping this area with around 90% overlap. The very high tensile strength of the SAT, causes the tightly wrapped layer to produce a significant ‘squeeze’ around the pipe. The layers of tape bond together through molecular fusion. Once applied, the final wrap retains all of the applied tension. The resulting high tension silicon sleeve can ‘squeeze’ down for 30 years or more (subject to environmental conditions). As there is no adhesive, this SAT will endure harsh temperature fluctuations, full submersion and UV light. 10. Once the high tension layer is complete, the operative may wrap back over the wrapped region with a low tension layer, which acts as impact protection. Sufficient tension should be applied to prevent air from becoming trapped therein and the operative can push down on the low tension layer to aid fusion.
Re-Test for Leakage 11. Referring to FIG. 1L of the drawings, the operative next re-checks the joint for leaking to ensure that the joint is properly sealed before moving on to the next step.
Armour 12. Referring to FIG. 2 of the drawings, the final step in the method involves applying the so-called ‘armour’. Thus, the operative removes the glass fibre bandage from its packaging and places it in water to activate the binder—this can be done by soaking or using a spray bottle containing water during the wrapping process. The bandage may, for example, comprise a woven fibre glass tape and may be pre-impregnated with 1,2-propaniedol, 2-ethyl-2-(hydroxymethyl), polymer with bis(isocyanatomethyl) benzene. Once moist, the bandage 30 is wrapped around the SAT wrapped region, starting in the centre and wrapping with a 50% (approximately) overlap. The operative wraps back and forth, covering around 20 mm beyond the end of the SAT wrap and ending with all strands on top of previously wrapped layers. Next, the operative quickly applies a stretch wrap 32 tightly over the bandaged area and compresses the region while it cures to ensure a close cell structure is formed, to maximise its strength. Once the armour 34 is hard (around 5 minutes, depending on the surrounding ambient temperature) the stretch wrap can be removed. Thus, in an exemplary embodiment, wherein the bandage is a woven fibre glass material pre-impregnated with 1,2-propaniedol, 2-ethyl-2-(hydroxymethyl), polymer with bis(isocyanatomethyl) benzene, the SAT wrapped or repair region wrapped therewith may be left for about 5 minutes, until the 1,2-propaniedol, 2-ethyl-2-(hydroxymethyl), polymer with bis(isocyanatomethyl) benzene has formed a hard outer shell substantially encompassing and extending along the length of the repair region. It will, of course, be appreciated that the time required for the joint to set may depend on several factors such as type of composite materials, ambient temperature and other environmental factors. The armour, in this exemplary embodiment, will be fully cured after around 60 minutes and can accept paint, if required, around 24 hours after the stretch wrap has been removed. Once cured, the layer provides a puncture proof barrier, safeguarding the seal against damage.
An liquid (e.g. water including steam) leak repair kit, particularly but not necessarily exclusively suitable for use in offshore applications, for repairing leaks on pipework up to 4 inches in diameter and with operating pressures up to 20 bar, according to an exemplary embodiment of the present invention is similar in many respects to the gas repair leak described above, and the method steps are substantially identical. However, as well as the high grade silicone self-amalgamating tape (SAT) and glass fibre bandage with a water activated binder, this kit includes a two-part curing silicone putty (instead of the non-curing silicone putty used in the gas repair method described above). This two-part, curing silicone putty is used to ‘plug’ the leak. Once mixed, applied and compressed, the putty cures, giving a bespoke silicone moulding. Between the process fluid and compression of the SAT layer (hereinafter described), this precisely fitting “gasket” ensures a good seal at higher pressures.

(9) The associated liquid leak repair method is substantially identical to the gas leak repair method described in detail above, except in that the putty, which is a two-part curing putty, must be prepared for use before application to the leakage area. To prepare the putty, the operative must mix the two-part putty by kneading and rolling the two parts together. The above-described liquid leak repair kit and the repair method is suitable for salt water, fresh water, waste pipes and steam. Indeed, it is to be understood that the ‘offshore’ leak repair kit has been specifically described above, but the kit and method so described is equally applicable to any liquid leak repair, and the present invention is not necessarily intended to be limited in this regard.

(10) It will be appreciated by a person skilled in the art, from the foregoing description, that modifications and variations can be made to the described embodiments without departing from the scope of the invention as defined by the appended claims. For example, the armour may be formed using woven carbon fibre bandage, instead of glass fibre. The bandage may, as described above, be impregnated with a matrix material or a component of a matrix material that is water soluble or water activated (for example, the matrix may be polyurethane). However, in alternative embodiments, the matrix component may be epoxy resin (and the kit may include a supply of epoxy resin) which, when applied to the woven bandage, sets and hardens to provide the required armour. Indeed, two part resins (for example, epoxy based resin systems) are available which may be suitable for provision in a kit form and mixed when required.