Note: Descriptions are shown in the official language in which they were submitted.
1
FLUID LEAK REPAIR
Field of Invention
This invention relates to a kit and method for repairing a fluid, such as gas,
water or steam,
leak in a pipe or conduit.
Background
A "fluid" as used herein is intended to be broadly interpreted as referring to
any gas or liquid
that flows under pressure in a pipe or conduit. Examples used herein include a
natural gas
supply pipe and a water/steam carrying pipe (particularly in, for example,
offshore
applications), but it is to be understood that the present invention is not
necessarily intended
to be limited in this regard.
Gas supply systems in commercial and domestic settings typically comprise a
network of
sections of rigid pipework connected together in a required configuration via
screw threaded
joints or coupling members, wherein a jointing paste is applied to the inner
surface of the
coupling member and/or the outer surface of a distal end of a pipe section and
the coupling
member is then screwed or pushed onto that end of the pipe section. A further
pipe section
can be similarly joined on the other side of the coupling member so as to
create a fluid-tight
seal between the two pipe sections that permits fluid flow therethrough.
Coupling members
of various shapes and configurations can be utilised to create straight
connections or bends,
for example, in the pipework and the ultimate aim is to create a sealed system
in the form of a
rigid network of permanently connected pipework through which fluid can flow
under
pressure.
Difficulties arise, however, in the event of a leak in one of the pipe
sections, which causes
fluid to leak from the system. In all cases, this would cause an unacceptable
pressure drop in
the fluid flow system, but in many cases (e.g. in a gas supply system), the
resultant health and
safety implications and danger posed by fluid leaking into the surrounding
atmosphere
creates an emergency situation that requires immediate remedial action. In the
case of, for
example, a gas supply system, the gas supply must be switched off unless and
until the leak
has been adequately repaired.
Permanently and reliably repairing a leak in a rigid pipe network, using known
methods, is a
complex and laborious task which must be undertaken by more than one trained
operative. In
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most cases, a permanent repair requires the affected section of pipework to be
removed and
replaced. However, this is not a straightforward task, as loosening and
removing a section of
pipe from the rigid network can result in other couplings and sections being
undermined.
US Patent Application no. 2007/0125437 describes a repair kit for a natural
gas pipe,
comprising a deformable leak sealant, a pressure sealant and a so-called
encapsulator. The
leak sealant is a curing or hardening putty, such as an epoxy putty, and is
applied at the
location of the leak. Next, a rubber tape (the "pressure sealant") is wrapped
around the leak
sealant, forcing it into a pinhole leak or joint leak as the epoxy putty
cures. Finally, an
encapsulator in the form of a cloth-like wrap that hardens after setting, is
applied around the
repair to maintain the leak sealant and pressure sealant in position so that
they maintain a seal
as the pressure is increased (i.e. as the pipe is brought back on line).
However, the described kitis only suitable for repairing natural gas pipes,
and requires the
pipe to be taken out of commission whilst the repair is undertaken, to allow
time for the putty
to harden and also for the encapsulator to harden, because it is these two
elements which
.. effect and maintain the seal once higher pressures are applied (whereas the
rubber tape used
in the described method does not continue to exert a significant force around
the pipe after
application). Thus, repairing a leak using the described kit and method takes
a relatively long
time, during which the pipe cannot be used at pressure.
US 20070207294 describes a shapeable absorbent mat having an absorbent layer
and a
forming layer secured to the absorbent layer. The forming layer is made of
shapeabele
material which may be liquid impermeable. The absorbent layer may be secured
to the
forming layer by an adhesive layer disposed between the absorbent layer and
the forming
layer.
EP 0574060 describes a method for repairing and reinforcing pressure-
supporting hollow
bodies, in particular deteriorated underwater pipelines, using a tape formed
from a plurality
of layers.
US 2015/0050854 describes a high temperature repair wrap for repairing or
strengthening an
item. The high temperature repair wrap incldes a fabric, where the fabric
includes one or
more fibres. The high temperature reparie wra further includes a hardening
material disposed
in the fabric. The high temperature repair wrap also includes a silicates
disposed within the
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hardening material. The fabric is configured to be wrapped around a portion of
an item.
Curing the hardening material is configured to forma a shell about the portion
of the item.
US 20020106464 describes a wrapped and curing substrate is secured with a
strap. The strap
has two clips, each having a prong. The prong of a first clip is slid in a
first direction into a
first portion of the wrapped substrate. A second clip is pulled away from the
first clip over a
substrate edge, and the prong of the second clip is slip into a second portion
of the wrapped
substrate in a direction opposite the first direction.
It would, therefore, be desirable to provide a kit and method of permanently
repairing a fluid
leak in a pipe or conduit that can be sued in a number of different
environments and that
ameliorates at least some of the issues outlined above. There is also a need
for a kit and
method for repairing such fluid leaks, to create a mechanically robust and
permanent seal.
There is also a need for a kit and method for repairing a fluid leak in a pipe
without requiring
several highly skilled operatives and a relatively long period of time, during
which the fluid
system is inoperable. It would also be desirable to provide a kit and method
for performing
permanent "live leak" repairs in a pipe or conduit at full pressure, if
required. Embodiments
of the present invention seek to address at least some of these needs.
Summary of the Invention
The method according to the invention can make use of a
fluid leak repair kit, comprising:
- a putty;
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a self-amalgamating tape; and
a composite material for use in encompassing the self-amalgamating tape, said
composite material comprising a flexible sheet or tape and a matrix component
for binding
the flexible sheet or tape, the matrix component comprising a resin or water-
activated matrix
component which, when cured, forms an outer shell.
In an exemplary embodiment, the flexible sheet or tape may comprise a woven
material. The flexible sheet or tape may comprise a fibre glass or carbon
fibre material. The
flexible sheet or tape may be pre-impregnated with the matrix material or a
component for
forming the matrix material. Optionally, the matrix component may be a
polymeric water
soluble or water-activated substance. The matrix component may be a
polyurethane resin. In
one exemplary embodiment, the matrix component may comprise 1,2-propaniedol, 2-
ethy1-2-
(hydroxyrnethyl), polymer with bis(isocyanatomethyl) benzene.
Optionally, the kit may further comprise a stretch wrap material for placing
over said
composite material whilst said matrix component cures.
The self-amalgamating tape may comprise a silicone self-amalgamating tape.
The kit may comprise a gas leak repair kit, wherein said putty may be a non-
curing
putty, such as a non-curing silicone putty.
The kit may comprise an liquid (e.g. water, including steam) leak repair kit,
wherein
said putty is a two-part curing putty, such as a two-part curing silicone
putty.
In accordance with one aspect of the present invention, there is provided a
method of
repairing a fluid leak in a pipe or conduit, characterised in that the method
comprises:
- applying a layer of putty to said pipe or conduit at a location of said
leak to seal it;
- wrapping, at tension, a self-amalgamating tape around said layer of putty
to cover it;
- contacting a flexible sheet or tape with either:
o a resin, or
o water to activate a water-activated matrix component;
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and
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encompassing the self-amalgamating tape with the flexible sheet or tape such
that the
resin or water-activated matrix component binds with the flexible sheet or
tape to form an
outer shell with the flexible sheet or tape to substantially surround the
joint.
The self-amalgamating tape may be wrapped at full tension, in which its width
is 75%
or less of its original width.
The method may further comprise, after wrapping, at tension, a self-
amalgamating
tape around said layer of putty to create a high tension wrapped region,
wrapping, at low
tension, a further layer of said self-amalgamating tape around said high
tension wrapped
region to cover it.
The method may be a method of repairing a gas leak, wherein said putty is a
non-
curing putty, such as a non-curing silicone putty.
The method may be a method of liquid e.g. water, including steam) leak repair,
wherein said putty is a two-part curing putty, such as a two-part curing
silicone putty.
The flexible sheet or tape may comprise a woven material. The flexible sheet
or tape
may comprise a fibre glass or carbon fibre material. The flexible sheet or
tape may be pre-
impregnated with the matrix material or a component for forming the matrix
material. The
matrix component may be a polymeric water soluble or water-activated
substance. The
matrix component may be a polyurethane resin. The matrix component may
comprise 1,2-
propaniedol, 2-ethyl-2-(hydroxymethyl), polymer with bis(isocyanatomethyl)
benzene.
The method may further comprise wrapping a stretch wrap material over said
composite material whilst said matrix component cures. The self-amalgamating
tape may
comprise a silicone self-amalgamating tape. The method may comprise cutting
lengths of
said self-amalgamating tape prior to wrapping each said length self-
amalgamating tape, at
tension, around said layer of putty. The lengths of self-amalgamating tape may
be cut at an
angle, such as substantially 45 .
Thus, and in contrast to the prior art described above, the leak repair
created using the
kit and/or method of the present invention relies on the quality and
application of the self-
amalgamating tape layer to make and maintain the seal, rather than the putty
or the outer
shell. This means that the repair is substantially instant and effective as
soon as the self-
amalgamating tape has been applied. The outer shell is only there to protect
the self-
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amalgamating tape layer from damage (which might otherwise undermine the
repair). There
is no cure time, and the repair can be affected "live" and under high pressure
if required. The
self-amalgamating tape layer, once applied, instantly exerts a continuous,
long-ten-n pressure
on the non-curing putty to make and maintain the seal; whereas, in contrast,
in the prior art,
the rubber tape layer is applied and used to press the putty into the leak
hole as it cures. This
type of tape does not continue to exert a significant compressive force around
the pipe after
application. Indeed, once applied, the tape breaks down and although it
conforms, the
compressive force weakens rapidly. It is, instead, the `encapsulator' which,
in the prior art,
holds the leak sealant and the pressure sealant in place so that they maintain
a seal as the
pressure is increased. In the present invention, the function of the outer
layer is just to
provide mechanical protection for the repair: the seal itself is made by the
self-amalgamating
tape layer. Because, in the prior art, the outer layer is an important part of
the overall seal,
the grade of the composite material used therefor may need to be much higher
than that
required for the present invention.
Brief Description of the Drawings
Figures 1A to IL 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
Figure 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
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.
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.
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:
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Preparation
1. When a leak is detected, its source must first be identified. Leak
detection solution
can be used for this purpose (see Figure 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 Figure 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 30cm either side of the leak area ¨ following
which, the
surface around the circumference of the pipe 10 can be sanded (see Figure 1C
of the
drawings) to achieve a smooth finish.
3. Referring now to Figure 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 Figure lE 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 Figure IF 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 Figure 1G of the drawings, a number of 20cm 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:
Joint size (inches) Number of strips of SAT required
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3/4 3
1 4
1 5
1 6
2 9
Each strip of SAT is cut using a 45 angle, as illustrated in Figure 1G.
7. Referring to Figure 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 3/4 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
Figure 1J of the
drawings.
9. Thus, starting about 25mm 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
Figure 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
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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 Figure 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 Figure 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 20mm 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-ethy1-2-
(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
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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.
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 are
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.
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.
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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.
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