Note: Descriptions are shown in the official language in which they were submitted.
~WO 95120125 PCT/GB95/00110
Improvements Relating to the Lining of Pipelines or
Passageways
This invention relates to the lining of pipelines and
passageways wherein a liner tube is fed into the pipeline or
passageway, and then is inflated onto the pipeline or
passageway surface. The liner, which is a flexible tubular
structure, includes a layer of resin absorbent material such
as a fibrous felt which is impregnated with a curable
synthetic resin, and the basis of the lining operation is
that when the lining tube is inserted and inflated up to the
size of the inner diameter of the pipeline or passageway, the
resin is cured so that the flexible liner turns into a rigid
lining lying on the pipeline or passageway surface.
This basic technology is now extremely well known, and is
practised throughout the world. The basic idea related to
this lining operation is disclosed in U.S. Patent No 4009063,
which discloses that the liner is pulled into the pipeline or
passageway and then is inflated using a fluid medium such as
air or gas or even a liquid such as water.
U.S. Patent No 4064211 discloses a modification of the basic
idea and in this U. S . patent it is suggested that the liner
after impregnation should be everted into and along the
passageway using a liquid to perform the eversion and to
provide a means whereby the inwardly travelling portion of
the liner is buoyantly supported before reaching the everting
face .
Modified methods for the insertion and inflation of the liner
have also been proposed in the past, and for example in the
paper entitled "Inflatable Terylene Reinforced Resin Pipe
Linings" by D Rhys-Jones presented at the First International
Conference on the internal and external positions of pipes on
WO 95/20125 . PCT/GB95/00110
2
September 9-11th, 1975 at the University of Durham, England,
it is disclosed that the liner may be pulled into the
pipeline or passageway, and then an expansion tube or hose is
everted into the liner when it has been pulled into the
pipeline or passageway and when it is still flexible and '
flat, in order to inflate the liner up to the pipeline or
passageway surface. An advantage of this method which is
identified by the description pull-in and inflate is that the
expansion tube which is used can be of relatively light
weight so that air can be used as the medium for expanding
the liner. Additionally, the expansion tube or hose can be
Withdrawn from the pipeline or passageway after the resin of
the liner has cured and the liner has turned into a rigid
lining, so that the expansion tube or hose can be reused.
In U.S. Patent No 4786345, it is explained how this pull-in
and inflate system can be used in connection with the lining
of what are called lateral pipelines or passageways, being
the service pipes which lead from for example domestic
dwellings or office buildings to a main line underground
sewer.
In the lining of these lateral pipes, difficulties arise
because it is not easy to position the liner inside the
lateral pipe from inside the main sewer, although a number of
attempts have been made to do this as indicated for example
in the following patent specifications:-
U.S. No. 4434115
PCT No. GB92/02287
EPA No. 0526521
The present invention is concerned with a method of inserting
resin impregnated flexible tubular liners into pipelines and
passageways, and in particular those pipelines and
O 95/20125 PCT/GB95/00110
3
passageways such as lateral pipes where access to one end of
the pipeline or passageway is difficult.
In accordance with the present invention there is provided a
method of lining a pipeline or passageway by means of a
length of flexible tubular liner which comprises or includes
resin absorbent material which is impregnated with a curable
synthetic resin comprises attaching one end, (the leading
end), of the liner to one end, the (leading end) of an
insertion rod means so that by pushing the rod, leading end
first, from one end of the pipeline or passageway to be
lined, to the other end of the pipeline or passageway, causes
the liner to be pulled into the pipeline or passageway, and
wherein the said leading end of the rod is connected to the
leading end of the liner by a means enabling the rod to pull
the liner into the pipeline or passageway, but when the rod
is retracted after the liner is so placed in the pipeline or
passageway it will become detached from the liner leaving the
liner in position.
Additionally, it is preferred that connected to the leading
end of the rod is a rope, cable or the like which extends
from the leading end of the rod, when it is at the remote end
of the pipeline or passageway, back to the insertion end of
the pipeline or passageway, and said rope, cable or the like
is trapped under restraining means which serve to hold the
flexible liner in a folded condition to which it is moved
prior, to insertion into the pipeline or passageway, and said
rope, cable or like serves to break or sever said holding
means when the rod is retracted from the pipeline or
passageway enabling the liner subsequently to be expanded.
The said holding means preferably comprises tapes or straps
which are wrapped around the folded liner. The tapes or
straps may be adhesive in nature, and may be applied at
WO 95/20125 PCT/GB95100110
4
spaced intervals. The said tapes or straps preferably are
of a nature so as to have good tensile strength in the
direction of the length of the tapes or straps, and poor tear
strength in a direction at right angles to the length of the
tapes or straps so that they will tear readily by virtue of
the rope, cable or the like effecting a tearing force thereon
as the rod is pulled back out of the pipeline or passageway.
The leading end of the rod may be provided with a head with a
groove to recieve a retaining strip which is adhesive in
nature, said strip being adhered to the leading end of the
liner, and being wrapped around the said head and anchored in
relation to the leading end of the rod. By this means, the
strip will serve as a pulling means when the rod is forced
into the pipeline or passageway to pull the lining tube along
with a rod into the pipeline or passageway, but when the rod
is retracted after insertion of the liner, the said strip
will peel away from the liner leaving it in position.
Where the pipeline or passageway is a lateral pipe
connection, the head on the rod may be such as to contact
the opposite side of the main sewer pipe when the rod is
fully inserted, which will ensure the accurate positioning of
the liner in relation to the lateral pipe.
When the lateral pipe has been inserted, and the rod has been
retracted, the lining may be inflated up to size by means of
an expansion tube or hose which can be everted directly into
the liner accurately in place in the pipeline or passageway.
The expansion tube or hose may be everted into the pipeline
or passageway using any suitable fluid such as a gas or
liquid or a combination of same, but regardless of the fluid
used, the liner will be held in the inflated condition on the
pipeline or passageway surface until curing of the resin
WO 95120125 PCT/GB95100110
takes place.
Equally, the liner may be of any suitable construction as
long as it is provided with at least one layer of resin
absorbent material which is impregnated with curable
synthetic resin which can be cured or will cure when the
liner is inflated onto the pipeline or passageway surface.
~n embodiment of the present invention will now be described,
by way of example, with reference to the accompanying
diagrammatic drawings, wherein;-
Fig. 1 shows a sectional elevation of a known flexible liner
construction, which is suitable for use in connection with
the method hereinafter described;
Fig. 2 shows the leading and trailing ends of the liner of
Fig. 1 with the insertion apparatus coupled thereto;
Fig. 3 shows an initial stage of the operation of inserting
the liner into a lateral pipeline;
Fig. 4 shows the completion of the insertion operation;
Fig. 5 shows how the insertion apparatus is retracted and the
function it performs in this retraction, leaving the liner in
place ready to be inflated;
Fig. 6 is a perspective view showing the inner end of the
liner and the insertion apparatus in the course of being
retracted;
Fig. 7 shows the liner when placed in the lateral pipeline
and in the course of being inflated to form the final lining;
WO 95/20125 PCT/GB95/00110
6
Fig. 8 shows the trailing end of the liner when inflated onto
the lateral passageway surface; and
Fig. 9 shows the leading end of the liner when similarly
inflated.
Referring to the drawings, and firstly to Fig. 1, a flexible
tubular liner 10 has the configuration shown and comprises an
inner layer 12 of resin absorbent material such as a needled
felt in one or more layers, and to the outside of the
absorbent material is an integral impermeable coating 14
comprising for example polyurethane film or the like. The
liner in this condition is flexible, and although the layer
12 is thoroughly impregnated with a curable synthetic resin,
the liner remains flexible until the resin cures. It is
shown in a flattened condition which is the normal form it
will take, but when it is applied to a pipeline or passageway
surface, it is inflated into circular form or to the form of
the passageway cross section.
In this method, the liner 10 is open at each end, and it is
specifically for insertion into a lateral pipeline or
passageway 16 as shown in Fig. 3 which extends from ground
level through a service connection 18 (which may be the
inside of a domestic dwelling) to a main line underground
sewer 20. The lateral passageway 16 is shown in this case as
having two bends, but it may be straight or it may be curved
or have a smaller or greater number of bends.
The liner 10 is dimensioned to the size of the lateral
passageway 16 which it is to line, and in this embodiment, "
the liner 10 is in fact folded as shown in Fig. 1 by dotted
lines into a U-shaped configuration. Before it is so folded
however, at one end, the leading end, which is illustrated by
reference numeral 22 in Fig. 6, has the outer film 14
CA 02156275 2005-06-13
provided with slits 24, so that the said end can flare bell-like when the
liner is inserted as will be
explained hereinafter. Additionally, at the leading end 22, at the extremity
thereof there is
applied by any suitable means a terminal strip 26 which looks into the main
sewer pipe 20 as will
be explained, and spaced from the strip 26 is applied a sealing ring 28 which
may be a
hydrotite TM sealing ring to seal against the surface of the pipeline or
passageway 16 and to
prevent roots from growing along the interface between the liner anal the
passageway surface.
The trailing end which is illustrated in Figure 2 by reference numeral 30 is
provided with a
similar sealing ring 32 which is spaced inwardly of the extremity oi'the end
30.
The strip 26 may be applied by any suitable aggressive adhesive to ensure firm
anchorage to the
outer surface of the liner 10.
To the leading end 22 of the liner is further attached an insertion apparatus
of which the main
elements are shown in Figure 2. Here, the insertion apparatus includes a
releasable attachment
member carrying adhesive tape which is attached to the liner. This apparatus
comprises a strap
retaining ball 34 which has a circumferential and diametrically arranged
groove 36 in which is
received a glass fibre tape length 38 having adhesive on each side thereof.
The tape 38 lies in the
groove 36 and is adhered to the ball 34, but in addition an end 40 of the tape
38 is applied to the
outer surface of the liner 10 so as to adhere thereto. This end 40 lies inside
the liner when it is
formed to U configuration as shown in Figure 1.
The ball 34 is carried on the end of an insertion rod 42 which is screwed to
the ball at 44 as
shown. The rod 42 may be made up in lengths 42A, 42B which are screwed
together so that
the rod can be of any suitable length for pushing the
21418138.1 7
WO 95/20125 PCT/GB95/00110
8
liner into position. It is appreciated that the rod 42 must
be capable of applying a considerable thrust force to insert
the liner into the pipeline or passageway, but also must be
of sufficient flexibility so that it can follow the contour
of the curves in the passageway 16.
The rod 42 is at least as long as the liner, and preferably
longer as it will be manipulated from ground level to push
the liner into position as will be described hereinafter.
Finally, attached to the leading end of the rod 42 is a pull
back rope 46 which is attached to the rod 42 by cable ties or
adhesive strips 48 or the like.
The pull back rope 46 lies in the inside of the U formed by
folding the liner as shown in Fig. 1, and is also shown in
Fig. 2, and finally the liner 10 is held in U-shaped
configuration by means of retention tapes 50 which are of a
nature having good longitudinal strength, but relatively poor
transverse tear strength so that as will be explained
hereinafter, the rope 46 can cut through the tapes 50 to
release them when the lining tube 10 has been placed in
position.
At the trailing end 30, the rope 46 is folded back on itself
as shown in Fig. 2, and at its extremity it is provided with
a holding knot 52.
Figs. 3, 4 and 5 illustrate the insertion method
diagrammatically. The leading end of the liner tube when
folded as shown in Fig. 2 is inserted into the pipeline or
passageway 16 from the service connection 18 by pushing on
the rod 42 by indicated by arrow 54. The ball 34 is the
leading element in this insertion process, and by virtue of
the force on the rod 42, indicated in dotted lines in Figs.
CA 02156275 2004-09-O1
9
3, 4 and 5, and through the medium of the pull tape 38 the
liner is forced into and along the passageway 16. Fig. 4
shows the liner fully in position, and it will be appreciated
that its length dimension is such as to cover the surface of
the liner to be lined. Fig. 4 also illustrates that a hold
back rope 56 may be attached to the trailing end of the liner
in order to control the in-feed of the liner so that it does
not "run away" under the effects of gravity and so that it
can be pulled back if necessary.
When the liner is in position as shown in Fig. 4, it is
simply a matter of pulling the rod 42 rearwards, which has
the effect of pulling back the rope 46 in a manner such that
as illustrated in Fig. 6, the rope folds back upon itself. A
number of effects take place at the leading end of the liner
and the first is that the rope 46 cuts through the first
retention tape 50 as shown in Fig. 6, and then the end of the
connecting strip 40 is peeled away from the leading end of
the liner. Arrow A in Fig. 6 illustrates the direction in
which the rod 42 is pulled back. As the rod continues to be
pulled back so it breaks the tapes 50 sequentially, and Fig.
shows the rod 42 retracted rearwardly by approximately half
the length of the passageway 16 to be lined. The rod 42 is
simply continued to be pulled rearwardly so that all of the
holding tapes 50 are severed, and the liner is now in
position ready to be inflated.
The rearmost holding tape 50 may be double wrapped in order
to retain the folded over portion of the rope 46, which
facilitates the breaking open of the last holding tape and
the retention of~'the rope end.
.y
The assembly is in fact made up in the form described under
factory conditions, and can be delivered to site, or assembly
can take place on site.
CA 02156275 2004-09-O1
Where appropriate and where possible, the leading end of the
liner tube 10 may be provided with a pull rope which leads
through the main sewer and to a location where pulling can
take place in order to assist the in-feed of the lining tube
10.
When the lining tube is being inserted, if the passageway 16
does have a number of bends as illustrated, insertion may be
assisted by a pull-in rope as described, and a remote
controlled camera may be utilized for checking when the
lining is in the correct position. These are established
techniques. Some bouncing or back and forth thrusting of the
push rod may be required in order to assist the insertion
process should it be that the lining and push rod become
locked or frictionally stuck against the passageway surface.
When the lining is in position as illustrated in Fig. 5, it
then has to be inflated as shown in Fig. 7. This inflation
procedure is in fact conventional insofar as an inflation
tube 60 is everted into and along the inside of the lining
tube 10 as shown in Fig. 7. The inflation tube is
dimensioned and inflated so that when the inflation step has
been completed, as shown in Fig. 9, the leading end of the
inflation tube 60 projects into the main sewer 20, thereby
flaring the leading end of the lining tube 10 as shown in
Fig. 9. The strip 26 which is applied to the outside of the
lining tube 10 as described in relation to Fig. 6 therefore
forms an anchor or catch on the surface of the main sewer 20
so that an effective positioning and location of the lining
tube 10 is achieved. Said strip 26 incidentally may comprise
a strip of felt material which itself is impregnated with a
curable synthetic resin, so that a hard collar will
eventually form in the vicinity of the junction between the
lateral passageway and the main sewer 20. The trailing end
CA 02156275 2005-06-13
of the inflation tube 60 is in fact belied out to give the effect described.
The said trailing end of the inflation tube 60 further has a shackle or like
coupling 62 connected
thereto, and a pull back rope 64 is connected to the shackle. When the lining
operation has been
complete therefore, the inflation tube 60 which may comprise a silicone coated
fabric hose, can
be pulled back so that the hose inverts and is peeled away from the cured
lining.
Where the resin is of a type which cures naturally i.e. it is an ambient cure
resin, the inflation
medium for the tube 60 may be any suitable such as air or water, but should it
be that the resin
requires heat to initiate and/or effect its cure, then a heated inflation
medium should be used.
Such medium may comprise hot water or steam or any other suitable fluid
medium. The fluent
medium may be inserted by any suitable apparatus and structure erected at
ground level and it
may assist in the performing of the inflation if the inflation tube is evened
part way into the
trailing end of the lining tube before it is folded and assembled and inserted
as described in
relation to Figs. 3 to 5.
Where hot water is used for inflation, it may be hot water at a 160°C
which is used in
conjunction with a silicone inflation tube. A suitable pumping apparatus may
be adopted for
example as described in our co-pending Canadian Patent Applic<~tion No. 2,
123,796 and the
inflation tube may require to be bounced so as to assist the inflation, by
cyclically varying the
pressure level inside the inflation tube. It is to be noted that control of
the inflation tube should
be effected so that it does not "run away" during the inflation operation.
When the inflation tube
has been fully inserted, the hot water is maintained in the inflation tube,
21418149.1 11
WO 95/20125 PCT/GB95/00110
12
and maybe circulated if desired, to maintain the temperature,
until the resin in the lining tube has cured sufficiently
hard so that the lining tube forms a cured hard lining which
remains firmly in position when the inflation tube is
removed.
Fig. 8 shows the trailing end of the lining tube when
inflated, and illustrates how the hydrotite sealing ring 32
forms a seal against the passageway surface. Fig. 9
illustrates how the leading end sealing ring 28 also seats
against the pipeline or passageway surface.
If the inflation ,tube is simply inserted by pouring water
into a suitable header apparatus, the insertion tube may be
held back manually, and various push rods may be used for
bouncing the tube to effect the efficient inflation of the
inflation tube inside the liner tube.
Instead of using an inflation hose which is inverted into the
lining tube to inflate same, an inflation tube or bladder may
be provided inside the lining tube before it is inserted in
the passageway. After insertion, the bladder is inflated to
apply the lining tube to the passageway surface and then the
bladder is peeled away by a pull back rope or the like
connected thereto and removed from the passageway, for
example as set forth in International Patent Application No
WO 93/16320.
The invention provides an extremely effective insertion
method for resin impregnated liner tubes, especially those
tubes which are to line passageways such as lateral
passageways, or "blind" passageways where access to the
remote end of the passageway is impossible of difficult. '
