EP0850381A1 - Pipe rehabilitation - Google Patents

Pipe rehabilitation

Info

Publication number
EP0850381A1
EP0850381A1 EP96927455A EP96927455A EP0850381A1 EP 0850381 A1 EP0850381 A1 EP 0850381A1 EP 96927455 A EP96927455 A EP 96927455A EP 96927455 A EP96927455 A EP 96927455A EP 0850381 A1 EP0850381 A1 EP 0850381A1
Authority
EP
European Patent Office
Prior art keywords
liner
pipeline
bladder
ofthe
resin
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP96927455A
Other languages
German (de)
French (fr)
Inventor
Kevin Francis Patrick Barry, Jr.
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of EP0850381A1 publication Critical patent/EP0850381A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L55/00—Devices or appurtenances for use in, or in connection with, pipes or pipe systems
    • F16L55/16—Devices for covering leaks in pipes or hoses, e.g. hose-menders
    • F16L55/162—Devices for covering leaks in pipes or hoses, e.g. hose-menders from inside the pipe
    • F16L55/165—Devices for covering leaks in pipes or hoses, e.g. hose-menders from inside the pipe a pipe or flexible liner being inserted in the damaged section
    • F16L55/1652—Devices for covering leaks in pipes or hoses, e.g. hose-menders from inside the pipe a pipe or flexible liner being inserted in the damaged section the flexible liner being pulled into the damaged section
    • F16L55/1654—Devices for covering leaks in pipes or hoses, e.g. hose-menders from inside the pipe a pipe or flexible liner being inserted in the damaged section the flexible liner being pulled into the damaged section and being inflated

Definitions

  • the present invention relates to rehabilitating existing pipelines of various lengths and diameters and, in particular, to a method for performing such rehabilitation.
  • Underground pipe systems deteriorate over time as a result of degradation of materials and outside influences such as tree roots, compression from above, expansion
  • PVC polyvinylchloride
  • the liner is fed into the existing pipe in a heated and softened form and then is
  • Hot cure systems are also susceptible to shrinkage both longitudinally and
  • the liner may move further along the pipe wall resulting in infiltration through the
  • the water causes what is known as a "cold spot" in the hot cure method.
  • This cold spot can inhibit the curing process which in turn leads to a failure ofthe line.
  • liners also normally require two access points to the host pipe.
  • the liner saturated with resin.
  • the liner is turned inside out or inverted and then forced into position in the pipeline by pressurised water normally produced by a static head of water
  • polyester resin systems are preferred.
  • the present invention seeks to overcome or at least ameliorate the above problems
  • the method includes the further steps of removing the bladder from the
  • the liner is formed of a felt-like material.
  • the bladder is coated with a release agent prior to insertion into the liner tube.
  • the gaseous fluid is compressed air.
  • the resin curing time may be adjusted by adjusting the ratios of base resin and
  • the resin may be cooled below ambient temperature during the set up process.
  • Figure 1 shows a pictorial representation ofthe liner prior to insertion into the host pipe
  • Figure 2 shows a sectional representation ofthe liner and bladder prior to insertion
  • Figure 3 shows a sectional part cutaway representation ofthe liner inserted into the pipeline.
  • Figure 4 shows a pictorial representation ofthe lining method where there is only a
  • the liner 5 is typically a felt-like
  • the felt is
  • extruded tubes 7 are coated with a release agent and inserted inside the felt tube or liner 5 to form an inflatable bladder.
  • the extruded tubes 7 are typically formed
  • bladder 7 may be inserted in the liner 5 before or after the felt is stitched or vulcanised.
  • lined is surveyed to access the length of pipeline to be lined and the location of any
  • junction distances are then marked on the liner 5 and a thin
  • This additional tubing 9 is optional, but desirable, in that it prevents excess resin
  • the liner 5 is next placed in a straight line on the ground and air plugs 10, 11
  • Air is supplied to the air plugs by air line 3 and to the bladder 7 by air line 4. The end of
  • the bladder 13 is spaced from the end ofthe liner 14 to prevent the end ofthe liner being
  • the liner 5 is then inflated through one or both ofthe air plugs 10, 11.
  • liner 5 is inflated sufficiently to form the desired shape ofthe pipeline 8 to be relined.
  • liner 5 such that the resin impregnates into the liner material.
  • the liner 5 can then be
  • the bladder 7 is then inflated using compressed air. Once inflated, the bladder 7 may be
  • deflated bladders 7 may be used inside the
  • liner 5 as a form of security. Should the outer bladder fail through bursting or fails to
  • the resin is then allowed to cure for the required time. During the curing process,
  • the liner 5 is held against the inner wall 19 of the pipeline 8 by the pressurised bladder 7.
  • the liner 5 is also attached to the inner wall 19 by means ofthe water resistant adhesive
  • the bladder 7 is
  • an electric drain cleaner can be used externally to cut the junctions from
  • the liner 5 is
  • bladder 7 are sealed to prevent escape of inflation air and a flow through plug 18 is
  • method includes introducing a
  • the liner 5 in the pipeline. This is shown in Figure 4.
  • the liner 5 has one end 20 sealed.
  • This end 20 is pushed toward the boundary trap 21 using hand rods (not shown) or the
  • the liner 5 can then be inflated using the internal bladder 7 in the usual
  • the cold cure technique enables long lengths of

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Lining Or Joining Of Plastics Or The Like (AREA)

Abstract

A method for rehabiliting existing pipelines in-situ is disclosed. A tubular liner (5) of a generally absorbent material is formed and at least one expandable bladder (7) is fed into the liner (5). The liner (5) is impregnated with a cold curable resin. The external surface of the liner and/or the internal surface of the pipeline (8) to be rehabilited is coated with a water resistant adhesive coating (16) prior to being fed into the pipeline (8) to be rehabilited together with its associated bladder (7). The bladder (7) is then inflated with a gaseous fluid to force the liner (5) against the internal wall (19) of said pipeline; and the inflation is maintained until the resin impregnated liner (5) has cured. The bladder (7) may then be removed from the cured liner (5).

Description

PIPE REHABILITATION
TECHNICAL FIELD
The present invention relates to rehabilitating existing pipelines of various lengths and diameters and, in particular, to a method for performing such rehabilitation.
BACKGROUND ART
Underground pipe systems deteriorate over time as a result of degradation of materials and outside influences such as tree roots, compression from above, expansion
and contraction and numerous other factors. In order to avoid the expense of excavating
the pipes and replacing them a number of "in situ" rehabilitation techniques have been developed. Most of these systems involve lining internally the old pipe using a plastic
liner which is fed into the old pipe via existing manholes or other existing access points. The liner is normally expanded into the required position against the internal wall ofthe existing pipe and cured to provide a rehabilitated pipe. Known techniques typically use polyvinylchloride (PVC) liners which are hot-
cured. The liner is fed into the existing pipe in a heated and softened form and then is
further heated and expanded using pressurised steam to force the liner against the internal wall ofthe existing pipe. The steam is then replaced by pressurised air and the liner allowed to cool and cure while still being held firmly against the internal pipe wall. Such systems have a number of disadvantages. They require expensive, specialised plant and equipment. For example, special semi-trailers, capable of carrying
large industrial generators and compressors. The capital equipment may cost in the
order of hundreds of thousands of dollars and is required by each crew to rehabilitate each pipeline. Each pipeline may take ofthe order of 6-12 hours to complete. In view ofthe high capital equipment costs, duplication of capabilities is very costly, making
response to market demands difficult.
Hot cure systems are also susceptible to shrinkage both longitudinally and
diametrically. This can produce a number of problems including doubts as to the structural integrity ofthe pipeline. Longitudinal shrinkage may result in infiltration and
blockages, particularly in respect of connections to branch lines. For example, where the
liner shrinks after the connections for the branch line have been cut, the cut out portion
ofthe liner may move further along the pipe wall resulting in infiltration through the
liner. Further, movement ofthe liner with shrinkage may result in the liner moving
across and blocking the branch connection.
It is also difficult to stop infiltration, or flow from a branch line during the
rehabilitation process. This can result in the heated liner coming into con tact with a
head of water. The water causes what is known as a "cold spot" in the hot cure method.
This cold spot can inhibit the curing process which in turn leads to a failure ofthe line.
Often hot cure PVC liners do not expand beyond the diameter ofthe host pipe.
This can result in an indentation not forming where the branch line connects to the
mainline. This makes location of laterals and branches very difficult and time
consuming. Further, hot cure PVC lines normally require their branch line connections
to be cut using an expensive remotely operated internal lateral cutter. Hot cure PVC
liners also normally require two access points to the host pipe.
Cold cure techniques are also known, most notably, a system using an inverted
liner saturated with resin. The liner is turned inside out or inverted and then forced into position in the pipeline by pressurised water normally produced by a static head of water
in a vertical inversion tube or pressure vessel being fed into an open end ofthe liner.
Though ambient or cold cure resins can be used with this system, thermo activated
polyester resin systems are preferred.
DISCLOSURE OF THE INVENTION
The present invention seeks to overcome or at least ameliorate the above problems
associated with the prior art by providing a cold cure method of lining existing pipelines
in-situ.
According to the present invention there is provided a method for rehabilitating
existing pipelines in-situ comprising the following steps:
a) forming a tubular liner of a generally absorbent material;
b) feeding at least one expandable bladder into said liner;
c) impregnating said liner with a cold curable resin;
d) coating an external surface of said liner and/or the internal surface ofthe
pipeline to be rehabilitated with a water resistant adhesive coating;
e) feeding said liner into the pipeline to be rehabilitated together with its
associated bladder;
f) inflating said bladder with a gaseous fluid to force the liner against the
internal wall of said pipeline; and g) maintaining said inflation until the resin impregnated liner has cured.
Preferably, the method includes the further steps of removing the bladder from the
cured liner. In a preferred form, the liner is formed of a felt-like material. For preference, the bladder is coated with a release agent prior to insertion into the liner tube.
Preferably, the gaseous fluid is compressed air.
The resin curing time may be adjusted by adjusting the ratios of base resin and
catalysts used. Further, where extended curing time is required, the resin may be cooled below ambient temperature during the set up process. BRIEF DESCRIPΗON OF THE DRAWINGS
A preferred embodiment ofthe present invention will now be described, by way of
example only, with reference to the accompanying drawings in which:
Figure 1 shows a pictorial representation ofthe liner prior to insertion into the host pipe;
Figure 2 shows a sectional representation ofthe liner and bladder prior to insertion
into the host pipe;
Figure 3 shows a sectional part cutaway representation ofthe liner inserted into the pipeline.
Figure 4 shows a pictorial representation ofthe lining method where there is only a
single access point and a boundary trap at one end.
MODES FOR CARRYING OUT THE INVENTION
Before discussing the process or method used in lining existing pipelines, an initial description ofthe materials used will be provided. The liner 5 is typically a felt-like
material with a flexible coating 6 applied to the outside ofthe felt. Typically, the felt is
formed from interlocked polyester with a thin membrane of polyurethane forming the flexible coating. It is tubed, stitched or vulcanised to form the shape ofthe pipeline. One or more extruded tubes 7 are coated with a release agent and inserted inside the felt tube or liner 5 to form an inflatable bladder. The extruded tubes 7 are typically formed
of PVC or other suitable plastics material although any form of flexible tubing capable
of forming an inflatable bladder containing compressed air may be used. The inflatable
bladder 7 may be inserted in the liner 5 before or after the felt is stitched or vulcanised.
The steps of a preferred method of lining an existing pipeline 8 will now be
discussed with reference to the accompanying drawings. Firstly, the pipeline 8 to be
lined is surveyed to access the length of pipeline to be lined and the location of any
relevant junctions. These junction distances are then marked on the liner 5 and a thin
flexible additional piece of tubing 9 is attached to the liner 5, as best shown in Figure 1.
This additional tubing 9 is optional, but desirable, in that it prevents excess resin
impregnating the liner 5 from bulging into the junctions and also assists in the cutting of
the junctions once the liner 5 is cured.
The liner 5 is next placed in a straight line on the ground and air plugs 10, 11
inserted into each end ofthe inflatable bladder 7. A short piece of tubing 12 is placed
over the end of bladder 7 adjacent the air plug 10, 11 and the air plug 10, 11 is inflated to
retain the bladder end 13 between the air plug 10, 11 and the short piece of tubing 12.
Air is supplied to the air plugs by air line 3 and to the bladder 7 by air line 4. The end of
the bladder 13 is spaced from the end ofthe liner 14 to prevent the end ofthe liner being
retained. The liner 5 is then inflated through one or both ofthe air plugs 10, 11. The
liner 5 is inflated sufficiently to form the desired shape ofthe pipeline 8 to be relined.
Once this is done both air plugs 10, 11 are pulled in opposite directions so as to stretch
the bladder 7 within the felt liner 5. This process eliminates any ridges. The air plugs
10, 11 are then deflated and removed. The bladder 7 is also deflated. A cold cure resin is then mixed and introduced between the bladder 7 and the felt
liner 5 such that the resin impregnates into the liner material. The liner 5 can then be
winched into position within the pipe 8 to be rehabilitated. As it is being winched into
position through an access hole 15, a water resistant adhesive coating 16 is applied to
outer flexible coating 6 ofthe liner 5. This water resistant coating 16 helps prevent
infiltration in the rehabilitated pipe 8.
Once the liner 5 is winched into the correct position within the pipe 8, a blank air
or mechanical plug 17 is inserted in one end ofthe liner inside the bladder end and a
flow through air plug 18 is inserted in the other end ofthe bladder in the same manner.
The bladder 7 is then inflated using compressed air. Once inflated, the bladder 7 may be
stretched to remove any ridges. A number of deflated bladders 7 may be used inside the
liner 5 as a form of security. Should the outer bladder fail through bursting or fails to
hold pressure for any reason, then the air plugs 17, 18 are easily removed and inserted
into a spare bladder.
The resin is then allowed to cure for the required time. During the curing process,
the liner 5 is held against the inner wall 19 of the pipeline 8 by the pressurised bladder 7.
The liner 5 is also attached to the inner wall 19 by means ofthe water resistant adhesive
16 previously applied. Following completion ofthe curing process, the plugs 17, 18 are
removed and the internal bladder 7 removed after deflation. Preferably, the bladder 7 is
attached to a cable which rotates the bladder tubing 7 while withdrawing it from the
liner.
Once this stage is completed, the junctions can be cut internally by use of a remote
control lateral cutter working in conjunction with a closed circuit TV (CCTV) camera. Alternatively, an electric drain cleaner can be used externally to cut the junctions from
relative access points.
Where there is only one access point to the pipeline 8 to be relined, the liner 5 is
pushed into position with hand rods or other suitable means. The remote ends ofthe
bladder 7 are sealed to prevent escape of inflation air and a flow through plug 18 is
inserted into the accessible end ofthe bladder 7. The process is then performed in a
similar manner to that described above.
In the case, where the only other access to the pipeline is a boundary trap, the
method according to a further aspect ofthe present invention includes introducing a
CCTV camera through the boundary trap to monitor and ensure correct positioning of
the liner in the pipeline. This is shown in Figure 4. The liner 5 has one end 20 sealed.
This end 20 is pushed toward the boundary trap 21 using hand rods (not shown) or the
like until the CCTV camera 22 shows that the liner 5 is correctly positioned within the
pipeline 8. The liner 5 can then be inflated using the internal bladder 7 in the usual
manner through the accessible end via flowthrough plug 18.
It will be understood that the present invention overcomes or at least ameliorates
the problems of shrinkage by use of an adhesive between the liner and the pipeline as
well as a cold cure technique. Further the cold cure technique enables long lengths of
pipe to be rehabilitated without the use of expensive, sophisticated equipment. It will be appreciated that further embodiments and exemplifications ofthe
invention are possible without departing from the spirit or scope ofthe invention
described and the invention is not limited to the particular embodiments described.

Claims

CLAIMS:
1. A method for rehabilitating existing pipelines in-situ comprising the following
steps:
a) forming a tubular liner of a generally absorbent material;
b) feeding at least one expandable bladder into said liner;
c) impregnating said liner with a cold curable resin;
d) coating an external surface of said liner and/or the internal surface ofthe
pipeline to be rehabilitated with a water resistant adhesive coating;
e) feeding said liner into the pipeline to be rehabilitated together with its
associated bladder;
f) inflating said bladder with a gaseous fluid to force the liner against the
internal wall of said pipeline; and
g) maintaining said inflation until the resin impregnated liner has cured.
2. A method according to claim 1 including the further step of removing the bladder
from the cured liner.
3. A method according to claim 1 or claim 2 wherein the liner is formed of a felt-like
material.
4. A method according to claim 3 wherein the felt-like material is formed from
interlocked polyester with a thin membrane of polyurethane forming a flexible outer
covering.
5. A method according to claim 1 wherein the bladder is coated with a release agent
prior to insertion into the liner tube.
6. A method according to claim 1 wherein the gaseous fluid is compressed air.
7. A method according to claim 1 including the step of cooling the resin impregnated
liner below ambient temperature prior to step (e) to lengthen the curing time ofthe resin.
8. A method according to claim 1 including the step of reinforcing the regions ofthe
liner which, in use, coincide with junction points along the pipeline.
9. A method according to claim 1 wherein the pipeline to be rehabilitated has access
at one end for feeding in of said liner and the only other access to the pipeline being a
boundary trap, the method including the step of introducing a TV camera through the
boundary trap to monitor and ensure correct positioning ofthe liner in the pipeline.
EP96927455A 1995-08-29 1996-08-28 Pipe rehabilitation Withdrawn EP0850381A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
AUPN5110/95 1995-08-29
AUPN5110A AUPN511095A0 (en) 1995-08-29 1995-08-29 Pipe rehabilitation
PCT/AU1996/000538 WO1997008487A1 (en) 1995-08-29 1996-08-28 Pipe rehabilitation

Publications (1)

Publication Number Publication Date
EP0850381A1 true EP0850381A1 (en) 1998-07-01

Family

ID=3789438

Family Applications (1)

Application Number Title Priority Date Filing Date
EP96927455A Withdrawn EP0850381A1 (en) 1995-08-29 1996-08-28 Pipe rehabilitation

Country Status (5)

Country Link
EP (1) EP0850381A1 (en)
AU (1) AUPN511095A0 (en)
CA (1) CA2230538A1 (en)
NZ (1) NZ315541A (en)
WO (1) WO1997008487A1 (en)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB9711294D0 (en) * 1997-06-03 1997-07-30 Autotte Jean Bernard Apparatus and method for lining of passageways
FI982416A (en) * 1998-11-06 2000-05-07 Suomen Putkisaneeraus Flow channel repair material
US6868870B2 (en) 2002-10-30 2005-03-22 Daniel Warren Method of lining a pipeline using a calibration hose
US7849883B2 (en) 2005-05-02 2010-12-14 Nuflow Technologies 2000 Inc. Liner assembly for pipeline repair and methods of installing same
US7270150B2 (en) 2005-06-14 2007-09-18 Warren Environmental, Inc. Method of lining a pipeline
FR2911078B1 (en) * 2007-01-05 2010-12-24 Inst Francais Du Petrole EXTENSIBLE REINFORCEMENT OF INTERNAL COATING RESTRUCTURING.
US8591695B2 (en) 2008-03-14 2013-11-26 Danny Warren Method and composition for lining a pipe
EP2844905B1 (en) * 2012-05-02 2018-10-17 Nu Flow Technologies 2000 Inc. Liner assembly for pipeline repair or reinforcement and method of installing same
EP3131736B1 (en) 2014-04-17 2021-09-15 Warren Environmental & Coating, LLC Method of lining and repairing a large diameter pipe
CN114458856A (en) * 2021-12-16 2022-05-10 堡森(上海)新材料科技有限公司 Device and method for repairing water-carrying structure of in-service pipeline

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU2665088A (en) * 1987-12-07 1989-06-08 Neil John Stephens Improved pipe liner and method
DE3906057A1 (en) * 1988-07-21 1990-01-25 Hans Mueller METHOD FOR LINING A PIPE PUT IN GROUND
GB9203005D0 (en) * 1992-02-13 1992-03-25 Insituform Group Ltd Improvements relating to the lining of pipelines or passageways
AU694172B2 (en) * 1994-04-11 1998-07-16 Cant, Richard Samuel Lining material

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9708487A1 *

Also Published As

Publication number Publication date
WO1997008487A1 (en) 1997-03-06
CA2230538A1 (en) 1997-03-06
AUPN511095A0 (en) 1995-09-21
NZ315541A (en) 1999-08-30

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