U.S. patent application number 12/966412 was filed with the patent office on 2011-05-05 for liner assembly for pipeline repair and methods of installing same.
This patent application is currently assigned to NUFLOW TECHNOLOGIES 2000 INC.. Invention is credited to Cameron Manners.
Application Number | 20110100498 12/966412 |
Document ID | / |
Family ID | 36763746 |
Filed Date | 2011-05-05 |
United States Patent
Application |
20110100498 |
Kind Code |
A1 |
Manners; Cameron |
May 5, 2011 |
LINER ASSEMBLY FOR PIPELINE REPAIR AND METHODS OF INSTALLING
SAME
Abstract
A liner assembly for pipeline repair and methods of installing
same. The liner assembly generally comprises an outer tubular
liner, an inner malleable inflatable bladder positioned
longitudinally within said liner, and a generally non-stretchable
strap positioned longitudinally within the malleable inflatable
bladder. The generally non-stretchable strap restricts longitudinal
over-expansion during positioning and inflation of the liner
assembly within a pipeline.
Inventors: |
Manners; Cameron; (Oshawa,
CA) |
Assignee: |
NUFLOW TECHNOLOGIES 2000
INC.
Oshawa
CA
|
Family ID: |
36763746 |
Appl. No.: |
12/966412 |
Filed: |
December 13, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11120040 |
May 2, 2005 |
7849883 |
|
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12966412 |
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Current U.S.
Class: |
138/98 |
Current CPC
Class: |
F16L 55/1653 20130101;
F16L 55/1654 20130101; F16L 55/1656 20130101; F16L 55/179
20130101 |
Class at
Publication: |
138/98 |
International
Class: |
F16L 55/16 20060101
F16L055/16 |
Claims
1-11. (canceled)
12. A liner assembly for installing a liner at a junction between a
main pipe and a lateral pipe, said liner assembly comprising: a
malleable inflatable bladder assembly for carrying a liner, said
malleable inflatable bladder assembly including a main portion and
a lateral portion; a flow through carrier contained within said
main portion; and a non-stretchable strap within said lateral
portion, wherein said non-stretchable strap is fixed at one end to
said flow through carrier contained in said main portion, and
adapted on an opposing end to be fixed to the end of said lateral
portion of said liner assembly during preparation for installation,
said non-stretchable strap serving to restrict longitudinal
over-expansion of the lateral portion during positioning and
inflation of the liner assembly within a pipeline.
13. The liner assembly of claim 12 wherein said malleable inflation
bladder further comprises a release plastic surrounding said
lateral portion, for placement between said lateral portion and
said liner.
14. The liner assembly of claim 12, wherein said non-stretchable
strap is vinyl.
15. The liner assembly of claim 12, wherein said flow through
carrier extends through said main portion and further comprises on
each end anchors for attachment of installation and retrieval
cables.
16. A method of installing a liner having main and lateral portions
at a junction between main and lateral pipes, said method
comprising the steps of: pulling a prepared liner assembly into
said pipeline, said liner assembly comprising a malleable
inflatable bladder assembly for carrying a wetted liner, said
malleable inflatable bladder assembly including a main portion and
a lateral portion, said main portion containing a flow through
carrier, said lateral portion containing a non-stretchable strap
extending from said flow through carrier to a sealed end of the
lateral portion, said non-stretchable strap serving to restrict
longitudinal over-expansion of the lateral portion during
positioning and inflation of the liner assembly within a pipeline,
introducing fluid into said malleable inflatable bladder assembly
to inflate said assembly so that said assembly expands to bring
said wetted liner into firm contact with interior surfaces of the
main and lateral pipes and conform said wetted liner to the shape
of said junction; maintaining said malleable inflatable bladder
assembly in an inflated condition for a time period sufficient for
said wetted liner to cure; deflating said malleable inflatable
bladder assembly; and retrieving said bladder assembly from said
pipeline by pulling said bladder assembly from said liner.
17. A liner kit for installing a liner in a pipeline, the kit
comprising: the liner assembly as defined in claim 12; a pair of
non-stretchable retaining sleeves for insertion into each end of a
liner assembly for preventing radial over-expansion during
inflation of the liner assembly; a pull block for insertion into
one end of the liner assembly, allowing for a pulling device to be
attached to the liner assembly; an inflation block for insertion
into a second end of the liner assembly, allowing for inflation of
the malleable inflatable bladder; and a resin kit comprising
components for preparing a resin for wetting said felt liner prior
to installation.
18. A liner kit for installing a liner in a pipeline, the kit
comprising: the liner assembly as defined in claim 13; a pair of
non-stretchable retaining sleeves for insertion into each end of a
liner assembly for preventing radial over-expansion during
inflation of the liner assembly; a pull block for insertion into
one end of the liner assembly, allowing for a pulling device to be
attached to the liner assembly; an inflation block for insertion
into a second end of the liner assembly, allowing for inflation of
the malleable inflatable bladder; and a resin kit comprising
components for preparing a resin for wetting said felt liner prior
to installation.
19. A liner kit for installing a liner in a pipeline, the kit
comprising: the liner assembly as defined in claim 14; a pair of
non-stretchable retaining sleeves for insertion into each end of a
liner assembly for preventing radial over-expansion during
inflation of the liner assembly; a pull block for insertion into
one end of the liner assembly, allowing for a pulling device to be
attached to the liner assembly; an inflation block for insertion
into a second end of the liner assembly, allowing for inflation of
the malleable inflatable bladder; and a resin kit comprising
components for preparing a resin for wetting said felt liner prior
to installation.
20. A liner kit for installing a liner in a pipeline, the kit
comprising: the liner assembly as defined in claim 15; a pair of
non-stretchable retaining sleeves for insertion into each end of a
liner assembly for preventing radial over-expansion during
inflation of the liner assembly; a pull block for insertion into
one end of the liner assembly, allowing for a pulling device to be
attached to the liner assembly; an inflation block for insertion
into a second end of the liner assembly, allowing for inflation of
the malleable inflatable bladder; and a resin kit comprising
components for preparing a resin for wetting said felt liner prior
to installation.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a division of U.S. patent application
Ser. No. 11/120,040, entitled LINEAR ASSEMBLY FOR PIPELINE REPAIR
AND METHODS OF INSTALLING SAME, filed on May 2, 2005, assigned to
the assignee of the present application, the disclosure of which is
expressly incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention generally relates to pipeline repair
and/or reinforcement and in particular to a liner assembly for
pipeline repair and methods of installing the same.
BACKGROUND OF THE INVENTION
[0003] Liners are commonly used to repair and/or reinforce ruptured
or weak areas in pipeline networks such as sewer systems and the
like. Lateral pipes i.e. those extending from a main pipe, are
especially susceptible to damage and have traditionally been
repaired by conventional excavation methods. As will be
appreciated, excavation methods are expensive, time consuming and
disruptive.
[0004] To avoid the problems associated with excavation methods,
"cure-in-place" pipeline repair technology has been developed to
allow pipelines to be repaired without requiring disruptive
excavation. During "cure-in-place" pipeline repair, a resin
impregnated liner is delivered to the pipeline section to be
repaired and is maintained in place at that location until the
curing process is complete.
[0005] A variety of installation systems for delivering
"cure-in-place" liners to pipeline sections to be repaired are used
in the industry. For example, the liner may be pushed along the
pipeline to its desired location by means of a series of push-rods.
As will be appreciated, transitional areas along the pipeline such
as bends and/or fittings create significant delivery problems as
the push-rods are unable to effectively move beyond these
transitional areas. Alternatively, and more commonly used in the
industry, the liner may be pulled along the pipeline to its desired
location using a winch and cable. U.S. Pat. No. 6,691,741 to
Manners shows a pull-in liner delivery method wherein an inflatable
bladder/resin impregnated felt liner assembly is pulled into the
pipeline to repair a damaged area pipeline section. Inversion
delivery where a liner is unrolled through itself by applied
pressure as it projects forwardly into a pipeline has also been
considered. U.S. Pat. No. 4,366,012 to Wood shows an inversion
delivery process wherein a felt liner, impregnated with uncured
resin is inverted into a pipeline in need of repair.
[0006] The installation of resin-impregnated liners in pipelines
presents certain challenges. For both push-in and pull-in delivery
methods, excessive friction during positioning of the liner imparts
longitudinal stresses on the liner, often resulting in stretching
of the liner. This stretching is undesirable as it may result in
weak regions of lined pipeline, and increase the likelihood of
future failure of the repaired pipeline section. With respect to
inversion delivery methods, due to the considerable pressures used
to unroll the liner, liner rupture is not uncommon. This rupture
problem is more prevalent when installing longer liners as greater
pressures are required during liner installation.
[0007] Pipelines containing bends (i.e. 22.degree., 45.degree.,
90.degree.) and/or other fittings (i.e. Y- and T-junctions) present
additional challenges. As practitioners in the industry are aware,
liners delivered by prior art installation systems are generally
prone to creasing in these areas of transition. Creases disrupt
fluid flow and may initiate an obstruction in the pipeline. Proper
installation of the liners requires the liners to be smoothly and
evenly urged into contact against the inner surface of the pipeline
to be repaired. Conventional PVC/vinyl inflatable bladders used in
prior art installation systems to urge liners into contact with the
inner surface of the pipeline in transitional areas have been found
to be deficient due to the nonmalleable nature of these inflatable
bladders. As a result, these inflatable bladders often introduce
folds and/or creases into the liners in these transitional areas.
There is clearly a need for an improved liner assembly that can
accommodate a wide variety of pipeline configurations.
[0008] It is therefore an object of the present invention to
obviate or mitigate at least one of the above described
disadvantages.
SUMMARY OF THE INVENTION
[0009] Accordingly, in one aspect there is provided a liner
assembly for pipeline repair comprising: [0010] an outer tubular
liner; [0011] an inner malleable inflatable bladder positioned
longitudinally within said liner; and [0012] a generally
non-stretchable strap positioned longitudinally within the
malleable inflatable bladder, said strap restricting longitudinal
over-expansion during positioning and inflation of the liner
assembly within a pipeline.
[0013] According to another aspect of the present invention,
provided is a liner kit for installing a liner in a pipeline, the
kit comprising: [0014] the liner assembly as defined above; [0015]
a pair of non-stretchable retaining sleeves for insertion into each
end of a liner assembly for preventing radial over-expansion during
inflation of the liner assembly; [0016] a pull block for insertion
into one end of the liner assembly, allowing for a pulling device
to be attached to the liner assembly; [0017] an inflation block for
insertion into a second end of the liner assembly, allowing for
inflation of the malleable inflatable bladder; and [0018] a resin
kit comprising components for preparing a resin for wetting said
felt liner prior to installation.
[0019] According to a further aspect of the present invention,
provided is a method of installing a prepared liner assembly in a
pipeline, comprising the steps of: [0020] pulling a prepared liner
assembly carrying a wetted liner into position in said pipeline,
said liner assembly including an outer felt liner tube, an inner
malleable inflatable bladder positioned longitudinally within said
felt liner tube, and a non-stretchable strap positioned
longitudinally within the inflatable bladder, said non-stretchable
strap being fixed to each end of said liner assembly to restrict
longitudinal over-expansion during positioning and inflation of the
liner assembly within said pipeline; [0021] introducing fluid into
said malleable inflatable bladder so that said malleable inflatable
bladder expands to bring said outer felt liner tube into firm
contact with interior surfaces of the pipeline; [0022] maintaining
said liner assembly in an inflated condition for a time period
sufficient for the outer felt liner tube to cure; [0023] deflating
said malleable inflatable bladder and retrieving said malleable
inflatable bladder from the liner assembly.
[0024] According to yet another aspect of the present invention,
provided is a liner assembly for installing a liner at a junction
between a main pipe and a lateral pipe, said liner assembly
comprising: [0025] a malleable inflatable bladder assembly for
carrying a liner, said malleable inflatable bladder assembly
including a main portion and a lateral portion; [0026] a flow
through carrier contained within said main portion; and [0027] a
non-stretchable strap within said lateral portion, [0028] wherein
said non-stretchable strap is fixed at one end to said flow through
carrier contained in said main portion, and adapted on an opposing
end to be fixed to the end of said lateral portion of said liner
assembly during preparation for installation, said non-stretchable
strap serving to restrict longitudinal over-expansion of the
lateral portion during positioning and inflation of the liner
assembly within a pipeline.
[0029] According to further aspect of the present invention,
provided is a method of installing a liner having main and lateral
portions at a junction between main and lateral pipes, said method
comprising the steps of: [0030] pulling a prepared liner assembly
into said pipeline, said liner assembly comprising a malleable
inflatable bladder assembly for carrying a wetted liner, said
malleable inflatable bladder assembly including a main portion and
a lateral portion, said main portion containing a flow through
carrier, said lateral portion containing a non-stretchable strap
extending from said flow through carrier to a sealed end of the
lateral portion, [0031] said non-stretchable strap serving to
restrict longitudinal over-expansion of the lateral portion during
positioning and inflation of the liner assembly within a pipeline,
[0032] introducing fluid into said malleable inflatable bladder
assembly to inflate said assembly so that said assembly expands to
bring said wetted liner into firm contact with interior surfaces of
the main and lateral pipes and conform said wetted liner to the
shape of said junction; [0033] maintaining said malleable
inflatable bladder assembly in an inflated condition for a time
period sufficient for said wetted liner to cure; [0034] deflating
said malleable inflatable bladder assembly; and [0035] retrieving
said bladder assembly from said pipeline by pulling said bladder
assembly from said liner.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] Embodiments will now be described more fully with reference
to the accompanying drawings in which:
[0037] FIG. 1 is a side view of a liner assembly for pipeline
repair;
[0038] FIG. 2 is an exploded perspective view of a portion of the
liner assembly;
[0039] FIG. 3 is a sectional view of another portion of the liner
assembly of FIG. 1;
[0040] FIGS. 4a and 4b are perspective views showing installation
of a pull block during assembly of the liner assembly;
[0041] FIGS. 5a to 5c are perspective views showing installation of
a retaining sleeve during assembly of the liner assembly;
[0042] FIGS. 6a to 6c are side views, partly in section, showing
installation of the liner assembly into a pipeline to be
repaired;
[0043] FIGS. 7a to 7f are side views showing preparation of a liner
assembly for installation into a T-junction within a pipeline;
[0044] FIG. 8 is a side view, partly in section, showing
installation of the liner assembly of FIGS. 7a to 7f into a
T-junction within a pipeline;
[0045] FIG. 9 is an enlarged side view of a portion of FIG. 8
during liner assembly position inspection; and
[0046] FIG. 10 is an enlarged side view of a portion of FIG. 8
during liner assembly retrieval.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0047] The liner assembly is generally provided in stock
manufactured lengths, preferably provided on a roll, with required
lengths being cut from stock. The liner assembly is generally
dimensioned to suit lateral pipelines ranging from 11/2 inches up
to 6'', but smaller or larger diameters (i.e. for use in mainlines)
can be used. The liner assembly provides a convenient pre-assembled
unit wherein a malleable inflation bladder is pre-positioned within
a liner during manufacture. In use, the liner assembly is cut to
size with the ends of the liner assembly being trimmed and sealed
with the appropriate installation gear. The liner assembly is then
impregnated with a resin, and subsequently positioned and inflated
to repair a damaged section of pipeline. The liner assembly also
provides a pre-positioned generally non-stretchable strap extending
the length of the liner assembly, the strap being fixed at each
sealed end, thus serving to prevent longitudinal stretching of the
malleable inflatable bladder and liner during positioning within a
pipeline.
[0048] Turning now to FIG. 1, a complete liner assembly is shown
and is generally identified by reference numeral 10. As can be
seen, the liner assembly 10 includes a liner segment 12, an
installation end 14 at one end of the liner segment 12, and an
inflation end 16 at the opposite end of the liner segment 12. To
facilitate positioning of the liner assembly 10 in the pipeline,
the installation end 14 is fitted with a pull block 36 that enables
attachment of a suitable pull mechanism (i.e. a winch). The liner
assembly is further fitted with an inflation block 38 at the
inflation end 16, so as to allow the interior area of the liner
assembly 10 to be inflated. The liner segment 12 is longitudinally
folded over itself and bound at twelve (12) to eighteen (18) inch
intervals using tape 18. Tapered sections 44 are also formed on the
liner assembly 10. This arrangement of the longitudinal folds and
the tapered sections allows the liner assembly to be manipulated
and moved to the correct location in the pipeline.
[0049] FIG. 2 better illustrates the liner segment 12. As can be
seen, liner segment 12 is multi-layered, comprising an outer felt
liner tube 22, an elongate malleable inflatable bladder 24
positioned therethrough, and a non-stretchable strap 26 positioned
within and along the length of the inflatable bladder 24. The liner
assembly, as better represented in partial cross-section in FIG. 3,
further comprises a plastic sheathing 23 over the outer surface of
the outer felt liner tube 22, and generally also comprises a
release plastic 40 positioned between the outer felt liner tube 22
and the elongate malleable inflatable bladder 24. Note that while
the plastic sheathing 23 may be fitted to the outside circumference
of the outer felt liner tube 22, in this embodiment it is adapted
to have a second longitudinal edge overlap a first longitudinal
edge by approximately 1.5 inches. To maintain the plastic sheathing
in place, the overlap may be temporarily tack welded. The malleable
inflatable bladder 24 is generally formed of rubber or silicone,
while the non-stretchable strap 26 is generally formed from woven
nylon or vinyl. It will be appreciated, however, that a skilled
person in the art may choose to use a suitable substitute material
for the above noted inflatable bladder 24 and/or strap 26. It will
also be appreciated that while the liner tube 22 is generally
referred to in this description as being constructed of felt, one
skilled in the art may choose to use an alternate substitute
material. Also shown in FIG. 2 is a pair of non-stretchable
retaining sleeves 32, 34 as well as the pull block 36 and the
inflation block 38. The retaining sleeves 32, 34 are generally made
of woven nylon or vinyl, but suitable alternatives may be readily
implemented as determinable by one skilled in the art.
[0050] To repair a damaged section of pipeline, using methods known
in the art, the length of liner required is first determined. To
ensure the liner assembly 10 covers the areas of the pipeline to be
repaired, and so that into the liner assembly incorporates a
sufficient length of liner that permits trimming and fitting of the
appropriate installation gear, generally an extra length (i.e. 10''
(250 mm)) is added to each end. A segment of liner assembly of
appropriate length is then cut and prepared as shown in FIG. 2.
[0051] As can be seen in FIG. 2, a portion of the outer felt liner
tube 22 and plastic sheathing 23 of the liner segment 12 is cut
back to expose a length of inflatable bladder 24, and where
applicable, release plastic 40. Note that for liners up to 2'' in
diameter, a release plastic may not be provided. As shown with
respect to FIG. 3, release plastic 40 surrounds the inflatable
bladder 24 along its entire length, and serves to facilitate easy
removal of the inflatable bladder 24 following installation. For
smaller diameter liners (up to 4''), generally 6'' of exposed
inflatable bladder is sufficient. For larger diameter liners,
generally 9'' of exposed inflatable bladder is sufficient. The
liner assembly is then further trimmed to expose a length (i.e.
4'') of strap 26 at each end 14, 16.
[0052] To prepare the segment of trimmed liner assembly for
installation, installation end 14 and inflation end 16 are sealed
with suitable installation gear. As shown in FIG. 4a, at
installation end 14, the pull block 36 is inserted into the
inflatable bladder 24. The inflatable bladder 24 in the region
surrounding the inserted pull block 36 is subsequently folded in or
cinched (as shown in FIG. 4b), onto the pull block 36, ensuring a
generally tight fit, sufficient to allow inflation of the
inflatable bladder later in the procedure. While preparing
installation end 14, strap 26 is tightly incorporated into the
folds of the inflatable bladder, or into the taping used to
securely maintain this arrangement at installation end 14, as shown
in FIG. 4b. Alternatively, strap 26 may be firmly attached to pull
block 36, with the inflatable bladder 24 being folded in or cinched
as described above. Inflation end 16 is similarly prepared (not
shown), substituting inflation block 38 for the pull block 36 . As
is the case for the installation end 14, strap 26 is tightly
incorporated into the folds or taping at inflation end 16, or
alternatively attached directly to inflation block 38.
[0053] With both ends 14, 16 sealed with the appropriate
installation gear, each end 14, 16 is further prepared by inserting
between the inflatable bladder 24 and the outer felt liner tube 22
a retaining sleeve 32, 34 (see FIG. 5a; only end 14 and retaining
sleeve 32 represented). The retaining sleeve 32, 34 is cut to a
length that starts at the front edge of the installation gear (pull
block 36 or inflation block 38) and reaches up into the liner at
least 6'' (See FIG. 5b). For liners having release plastic 40, the
retaining sleeve 32, 34 is positioned between the release plastic
40 and the inflatable bladder 24. As shown in FIG. 5c, at each end
14, 16, the retaining sleeve 32, 34 and release plastic 40 is
folded in, over the taped ends previously prepared, and securely
taped. Each end 14, 16 is then further secured using suitable
clamps 41 (i.e. gear clamps) to ensure a tight fit around the
blocks positioned therein.
[0054] While the above description teaches ends 14, 16 being sealed
in two stages (i.e. first taped and secondly clamped), the process
is merely exemplary and a person skilled in the art may choose to
seal each end about the respective gear in an alternate suitable
manner so as to achieve substantially sealed ends.
[0055] With the liner assembly sealed at both ends 14, 16 with the
appropriate installation gear, the outer felt liner tube 22 is
impregnated with an appropriate resin (i.e. epoxy). The process of
impregnating the outer felt liner tube 22 is commonly referred to
as "wetting". To wet the outer felt liner tube, a portion of the
resin is delivered to the space between the outer felt liner tube
22 and the inflatable bladder 24. If a release plastic 40 is
provided, the resin is delivered to the space immediately adjacent
the outer felt liner tube 22. To move the resin slug through the
liner assembly 10, rollers are used in a manner known in the art.
To ensure a complete wet out procedure, it is helpful to apply
excess resin to both ends of the outer felt liner tube 22.
[0056] After the outer felt liner tube 22 of the liner assembly 10
has been wetted, the plastic sheathing 23 on the outside surface of
the outer felt liner tube 22 is scored to facilitate migration of
the resin out of the outer felt liner tube 22. Contact of the resin
with the pipeline being repaired ensures that the liner being
installed is fixed in place. The outside surface of plastic
sheathing 23 is then wiped to ensure a clean dry surface. Referring
back to FIG. 1, the liner assembly is then longitudinally folded
and taped at approximately 12 to 18'' intervals 42 to retain this
folded arrangement. To facilitate entry and/or movement of the
liner assembly in a pipeline, the leading edge of the outer felt
liner tube 22 is taped to form a tapered configuration 44. To
facilitate the release of the inflatable bladder, a silicone
release gel may be added to each end 14, 16 of the liner assembly.
To installation end 14, a winch cable 46 is attached to pulling
block 36, with the optional use of devises 48. To inflation end 16,
an air line 50 is attached to inflation block 38.
[0057] FIGS. 6a through 6c show the liner assembly 10 in a linear
section of pipeline. To install the liner assembly, a winch (not
shown) is used to pull the liner assembly into a pipeline P to be
repaired and/or reinforced via winch cable 46, as shown in FIG. 6a.
Once the liner assembly is at the desired location within the
pipeline, an air pump (not shown) is operated to supply air through
air line 50, connected to inflation block 38. Air fed through the
air line 50 passes through inflation block 38 and into the internal
reservoir 51 of the inflatable bladder 24. The inflatable bladder
24 is inflated until the liner assembly 10 expands to the point
where the outer felt liner tube 22 is urged against and firmly
contacts the interior surface 52 of the pipeline as shown in FIG.
6b. During inflation, the taped portions of the liner assembly
release, allowing the liner assembly, and surrounding plastic
sheathing 23 to expand and contact the interior surface 52. The
liner assembly is then maintained in this condition for a time
period sufficient to enable the wetted outer felt liner tube to
cure.
[0058] Following curing of the outer felt liner tube 22, the air
within the internal reservoir 51 is released through the inflation
block 38 and air line 50 (see FIG. 6c). To facilitate this process,
the air pump may be used to evacuate air from the internal
reservoir, allowing the inflatable bladder 24 to resume its natural
flat state. Once evacuated, the inflatable bladder is then
withdrawn from the pipeline via winch cable 46, leaving the cured
outer felt liner tube 22 in position within the pipeline.
[0059] The appropriate air pressure for inflating the inflatable
bladder 24 depends on the diameter of the liner assembly. In
general, liner assemblies having a diameter ranging from 3'' to 6''
are inflated to approximately 12 to 15 pounds per square inch
(psi). Liner assemblies of smaller diameter (i.e. 11/2 '' and 2''
liners) are inflated to approximately 24 psi. During the inflation
process, the air pressure should be sufficient to break the tape 42
spaced along the longitudinally folded liner assembly, allowing the
liner assembly to fill the pipeline being repaired.
[0060] Although the installation of the liner assembly has been
shown with respect a linear section of pipeline, the liner assembly
may also be used to install a liner in a bent section of pipeline.
The ability of the liner assembly to adapt to bends (i.e.
22.degree., 45.degree., 90.degree.) is provided by the malleable
nature of the inflatable bladder used in the liner assembly. As the
liner assembly is inflated in a transitional area, the bladder not
only stretches to accommodate the air pressure contained therein,
but conforms to the bend so as to ensure the resin-impregnated
liner is urged into contact with all surfaces of the transitional
area. The inflatable bladder achieves this by allowing variable
stretching, i.e. stretching less at the inside edge while
stretching more at the outside edge of the bend. Prior art systems
that used woven nylon or vinyl bladder systems could not achieve
this variable stretching, ultimately resulting in creases and/or
folds being formed in the resin-impregnated and resultant cured
liner. The reduction and/or elimination of these creases results in
greater fluid flow in the repaired section and well as a reduction
in the likelihood of debris retainment and possible
obstruction.
[0061] Turning now to FIGS. 7 to 10, an alternative embodiment of a
liner assembly for installing a liner at a T-junction within a
pipeline is shown and is generally identified by reference numeral
100. As can be seen, the liner assembly 100 includes a T-shaped
malleable bladder assembly 102 having a main portion 104 and a
lateral portion 106 connected by a fused T-joint 108. The lateral
portion 106 further comprises a release plastic 110 and a
non-stretchable strap 112. The main portion 104 further comprises a
flow-through carrier 114 extending therethrough. Strap 112 is fused
to the flow-through carrier 114 in the region of the fused T-joint
108.
[0062] FIGS. 7a through 7f show the T-shaped bladder assembly 102
being prepared for installation. FIG. 7a shows the insertion of a
retaining sleeve 116 on end portion 118 of the lateral portion 106.
To facilitate positioning, the end portion 118 is further fitted
with a pull block 120 (see FIG. 7b) adapted to be coupled to an
installation cable 122 and winch (not shown). The lateral portion
106 of the inflatable bladder and the surrounding release plastic
110 is subsequently folded in or cinched (as shown in FIG. 7c),
onto the pull block 120, ensuring a generally tight fit, sufficient
to allow inflation of the T-shaped bladder assembly 102 later in
the procedure. Note that strap 112 is tightly incorporated into the
folds of the cinched lateral portion 106, thereby restricting the
extent of longitudinal stretching in lateral portion 106 by
limiting the distance between end portion 118 and the flow-through
carrier 114 to which the strap 112 is fused. As shown in FIGS. 7c
and 7d, preparation of the lateral portion 106 further comprises
the placement of suitable clamps 124 (i.e. gear clamps) to ensure a
tight fit around the pull block positioned therein.
[0063] As shown in FIGS. 7c and 7d, each end of the main portion
104 receives a non-stretchable retaining sleeve 126, 128 so as to
prevent radial overexpansion of the bladder assembly upon
inflation. This arrangement is then sealed to the respective ends
of the flow-through carrier 114 extending therethrough using tape
130 and suitable clamps 132.
[0064] With the lateral portion 106 and the main portion 104
prepared for installation, the liner segments can be placed into
position on the T-shaped bladder assembly. Note that all liner
segments are wetted (i.e. impregnated with resin) prior to
installation. As shown in FIG. 7d, the lateral liner segment 140 is
placed over the lateral portion 106. To ensure a complete
transition to the main portion of the pipeline, the lateral liner
segment 140 is provided with a flange 142. To complete the liner
assembly, a mainline segment 144 is then placed into position. The
mainline segment 144 is configured to cover the flange 142 of the
lateral liner segment 140 and envelop the main portion 104. As
such, a complete lateral to mainline transition is achieved. To
complete the preparation, an installation cable 134 is attached to
the leading end 114a of the flow-through carrier 114 and extends to
a winch (not shown). A retrieval cable 136 is attached to the
training end 114b of the flow-through carrier 114 and extends to a
winch (not shown). A hose 138 having one end coupled to a fluid
source such as an air pump (not shown) extends through the
flow-through carrier 114 and is in fluid communication with the
internal area of the bladder assembly via a valve (not shown).
[0065] Turning now to FIGS. 8 to 10, installation of the T-shaped
bladder assembly 102 into a pipeline having a T-junction will be
described. With the liner assembly prepared for installation, the
liner assembly 100 is launched through a manhole 146 and into a
main pipe 148. A remote controlled camera 150 may also be placed in
the main pipe 148. The installation cable 122, which has been
previously fed through a lateral pipe 152 that is connected to the
main pipe 148 to define the T-junction to be repaired and/or
reinforced, is then used to pull the lateral portion 106 of the
bladder assembly 102 into the main pipe 148. Once the full length
of the lateral portion 106 of the bladder assembly 102 is in the
main pipe 148, the installation cables 122 and 134 are pulled
simultaneously. Pulling of the installation cable 134 advances the
flow-through carrier 114 and hence bladder assembly 102 towards the
T-junction defined by the main and lateral pipes 148 and 152
respectively. Pulling of the installation cable 122 advances the
lateral portion 106 of the bladder assembly 102 up into the lateral
pipe 152. During this stage, the remote controlled camera 150 is
used by the technicians to assist in the proper positioning of the
liner at the T-junction as shown in FIG. 9.
[0066] With the liner assembly 100 properly positioned at the
T-junction, the air pump is operated to feed air into the hose 138.
Air fed into the hose 138 enters the bladder assembly 102 until
both the lateral portion 106 and main portion 104 are inflated so
as to force the lateral liner segment 140 and mainline liner
segment 144 into contact with the interior surfaces of the main and
lateral pipes 148 and 152 as shown in FIG. 9. As in the previous
embodiments, the bladder assembly 102 is maintained in this
condition until the liner cures.
[0067] Following curing of the liner, the air pump is operated to
evacuate air from the bladder assembly 102, allowing the lateral
portion 106 and main portion 104 to deflate (See FIG. 10). Once
deflated, the retrieval cable 136 is pulled to remove the
flow-through carrier 114 and attached bladder assembly 102 from the
cured-in-place liner. With the bladder assembly 102 and
flow-through carrier 114 separated from the liner, the retrieval
cable 136 is pulled until the assembly is removed from the pipeline
via the manhole 146.
[0068] Although the liner assembly 100 is shown for use in
installing a liner at a T-junction between a lateral pipe and a
main pipe, those of skill in the art will appreciate that the
installation system can be used to install liners in other types of
pipe junctions.
[0069] It will be appreciated from the above description that the
non-stretchable strap and non-stretchable retaining sleeves serve
to control the expansion of the malleable inflatable bladder. The
strap is used to prevent longitudinal over-expansion of the
inflatable bladder during both installation and inflation, while
the retaining sleeves serve to prevent radial over-expansion (i.e.
ballooning) at respective ends of the liner assembly. As indicated
above, while the strap and retaining sleeves are generally
manufactured from woven nylon or vinyl, suitable non-stretchable
alternatives may also be used to achieve the desired expansion
control.
[0070] Although preferred embodiments of the present invention have
been described, those of skill in the art will appreciate that
variations and modifications may be made without departing from the
spirit and scope thereof as defined by the appended claims.
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