U.S. patent application number 11/354720 was filed with the patent office on 2006-06-22 for resin impregnation tower for cured in place liner.
Invention is credited to Franklin Thomas Driver, Weiping Wang.
Application Number | 20060130753 11/354720 |
Document ID | / |
Family ID | 34590742 |
Filed Date | 2006-06-22 |
United States Patent
Application |
20060130753 |
Kind Code |
A1 |
Driver; Franklin Thomas ; et
al. |
June 22, 2006 |
Resin impregnation tower for cured in place liner
Abstract
A resin impregnation tower for continuously impregnating the
resin impregnable layer of a tubular cured in place liner is
provided. The tower is of a height to provide sufficient resin
pressure head to impregnate the resin impregnable layer fully. A
cured in place liner having at least one layer of resin impregnable
material is fed into the top of the tower, drawn down about a
roller at the bottom, removed from the top of the tower and then
wrapped with an outer impermeable coating. The impregnated liner is
suitable for pull-in-and-inflate method of installation or may be
inverted. For liners formed with an inner impermeable layer, the
liner is suitable for curing with steam.
Inventors: |
Driver; Franklin Thomas;
(St. Charles, MO) ; Wang; Weiping; (Ballwin,
MO) |
Correspondence
Address: |
Michael I. Wolfson, Esq.;Greenberg Traurig, LLP
20th Floor
200 Park Avenue
New York
NY
10166
US
|
Family ID: |
34590742 |
Appl. No.: |
11/354720 |
Filed: |
February 15, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10704461 |
Nov 7, 2003 |
|
|
|
11354720 |
Feb 15, 2006 |
|
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Current U.S.
Class: |
118/423 |
Current CPC
Class: |
B29C 63/065 20130101;
F16L 55/1656 20130101; F16L 55/1654 20130101; B29C 53/382 20130101;
Y10T 156/1013 20150115; B29L 2023/006 20130101; B29C 63/0021
20130101 |
Class at
Publication: |
118/423 |
International
Class: |
B05C 3/00 20060101
B05C003/00 |
Claims
1. An apparatus for impregnating a resin impregnable material,
comprising an enclosed vertical column of sufficient height to
impregnate the resin impregnable material, the column having an
upper portion and a lower portion, the tubular material to be fed
into the upper portion of the column to the lower portion and
removed from the upper portion of the column after passing through
resin therein.
2. The apparatus of claim 1, wherein the column has a substantially
rectangular cross-section with two opposed side walls and two
opposed edge walls.
3. The apparatus of claim 1, wherein the column is at least five
feet in height.
4. The apparatus of claim 1, wherein the column has an open top and
the impregnable material is fed into the open top.
5. The apparatus of claim 1, including a roller mounted in the
lower portion of the column at a depth sufficient to impregnate the
impregnable material for changing direction of the tubular material
as it passes through the column.
6. The apparatus of claim 1, including at least one pulling roller
mounted at the top of the column.
7. The apparatus of claim 6, including a roller at one side wall to
facilitate entry of the impregnable material into the column.
8. The apparatus of claim 7, including a pair of cooperating
rollers for facilitating the impregnable material entering the
column.
9. The apparatus of claim 8, wherein at least one of the rollers is
a drive roller.
10. The apparatus of claim 2, including a pair of compression
rollers mounted at the top of the column for facilitating
withdrawal of the impregnated material as it exits the column.
11. The apparatus of claim 10, wherein at least one of the
compression rollers are drive rollers.
12. An apparatus for impregnating a tubular resin impregnable
material, comprising a hollow vertical tower of sufficient height
to impregnate the resin impregnable material, the tower having a
roller at a lower portion for changing direction of the tubular
material as it is fed into the upper portion of the column to the
lower portion and removed from the upper portion of the column
after passing through resin in the tower.
13. The apparatus of claim 12, wherein the tower has a
substantially rectangular cross-section and with two opposed side
walls and two opposed edges.
14. The apparatus of claim 12, wherein the tower is at least five
feet in height.
15. The apparatus of claim 12, wherein the tower has an open top
and at least one roller mounted at the top adjacent one of the side
walls and the tubular member is fed over the roller and into the
tower at the top.
16. The apparatus of claim 15, further including at least one
pulling roller mounted at the top of the tower.
17. The apparatus of claim 16, including two rollers at the top of
the tower.
18. The apparatus of claim 17 wherein both rollers are pulling
rollers.
19. The apparatus of claim 15, further including a pair of
compression rollers mounted at the top of the tower for the
impregnated tubular material to pass therethrough as it is removed
from the tower.
20. A resin impregnation tower for impregnating a cured in place
liner including at least one layer of resin impregnable material
comprising a vertical column of sufficient height to impregnate the
resin impregnable layer, the column having a roller at a lower
portion for changing direction of the tubular material as it is fed
into the upper portion of the column to the lower portion and
pulled out of the upper portion of the column after passing through
resin in the tower.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of co-pending application
Ser. No. 10/704,461 filed on Nov. 7, 2003.
BACKGROUND OF THE INVENTION
[0002] This invention relates to cured in place liners for
trenchless rehabilitation of existing conduits and pipelines, and
more particularly to an impregnation tower for the continuous
impregnation of cured in place liners that may have an inner
impermeable layer to be wrapped with an outer impermeable layer for
the trenchless rehabilitation of existing conduits by pulling in
and inflating.
[0003] It is generally well known that existing conduits and
pipelines, particularly underground pipes, such as sanitary sewer
pipes, storm sewer pipes, water lines and gas lines that are
employed for conducting fluids frequently require repair due to
fluid leakage. The leakage may be inward from the environment into
the interior or conducting portion of the pipelines. Alternatively,
the leakage may be outward from the conducting portion of the
pipeline into the surrounding environment. In either case of
infiltration or exfultration, it is desirable to avoid this type of
leakage.
[0004] The leakage in the existing conduit may be due to improper
installation of the original pipeline, or deterioration of the pipe
itself due to normal aging, or the effects of conveying corrosive
or abrasive material. Cracks at, or near pipe joints may be due to
environment conditions such as earthquakes, or the movement of
large vehicles on the overhead surface, or similar natural or
man-made vibrations, or other such causes. Regardless of the cause,
such leakages are undesirable and may result in waste of the fluid
being conveyed within the pipeline, or result in damage to the
surrounding environment and possible creation of dangerous public
health hazards. If the leakage continues it can lead to structural
failure of the existing conduit due to loss of soil and side
support of the conduit.
[0005] Because of ever increasing labor and machinery costs, it is
increasingly more difficult and less economical to repair
underground pipes or portions that may be leaking by digging up the
existing pipe and replacing the pipe with a new one. As a result,
various methods have been devised for the in place repair or
rehabilitation of existing pipelines. These new methods avoid the
expense and hazards associated with digging up and replacing the
pipe or pipe sections, as well as the significant inconvenience to
the public during construction. One of the most successful pipeline
repair or trenchless rehabilitation processes that is currently in
wide use is called the Insituform.RTM. Process. The Insituform
Process is described in detail in U.S. Pat. No. 4,009,063, U.S.
Pat. No. 4,064,211 and U.S. Pat. No. 4,135,958, the contents of
which are all incorporated herein by reference.
[0006] In the standard practice of the Insituform Process an
elongated flexible tubular liner of a felt fabric, foam or similar
resin impregnable material with an outer impermeable coating that
has been impregnated with a thermosetting curable resin is
installed within the existing pipeline. In the most widely
practiced embodiment of that process, the liner is installed
utilizing an eversion process, as described in the '211 and '958
Insituform patents. In the eversion process, radial pressure
applied to the interior of an everted liner presses it against and
into engagement with the inner surface of the pipeline as the liner
unfolds along the length of the pipeline. The Insituform Process is
also practiced by pulling a resin impregnated liner into the
conduit by a rope or cable and using a separate fluid impermeable
inflation bladder or tube that is everted within the liner to cause
the liner to cure against the inner wall of the existing pipeline.
Such resin impregnated liners are generally referred to as
"cured-in-place-pipes" or "CIPP liners" and the installation is
referred to a CIPP installation.
[0007] Conventional cured in place flexible tubular liners for both
the eversion and pull-in-and-inflate CIPP installations have an
outer smooth layer of relatively flexible, substantially
impermeable polymer coating in its initial state. The outer coating
allows a resin to be impregnated into the inner layer of resin
impregnable material, such as felt. When everted, this impermeable
layer ends up on the inside of the liner with the resin impregnated
layer against the wall of the existing pipeline. As the flexible
liner is installed in place within the pipeline, the pipeline is
pressurized from within, preferably utilizing an eversion fluid,
such as water or air to force the liner radially outwardly to
engage and conform to the interior surface of the existing
pipeline. Cure of the resin is initiated by introduction of hot
curing fluid, such as water into the everted liner through a
recirculation hose attached to the end of the everting liner. The
resin impregnated into the impregnable material then cures to form
a hard, tight fitting rigid pipe lining within the existing
pipeline. The new liner effectively seals any cracks and repairs
any pipe section or pipe joint deterioration in order to prevent
further leakage either into or out of the existing pipeline. The
cured resin also serves to strengthen the existing pipeline wall so
as to provide added structural support for the surrounding
environment.
[0008] When tubular cured in place liners are installed by the
pull-in-and-inflate method, the liner is impregnated with resin in
the same manner as in the eversion process and pulled into and
positioned within the existing pipeline in a collapsed state. In a
typical installation, a downtube, inflation pipe or conduit having
an elbow at the lower end is positioned within an existing manhole
or access point and an everting bladder is passed through the
downtube, opened up and cuffed back over the mouth of the
horizontal portion of the elbow and inserted into the collapsed
liner. The collapsed liner within the existing conduit is then
positioned over and secured to the cuffed back end of the inflation
bladder. An everting fluid, such as water, is then fed into the
downtube and the water pressure causes the inflation bladder to
push out of the horizontal portion of the elbow and cause the
collapsed liner to expand against the interior surface of the
existing conduit. The eversion of the inflation bladder continues
until the bladder reaches and extends into the downstream manhole
or second access point. At this time the liner pressed against the
interior surface of the existing conduit is allow to cure. Cure is
initiated by introduction of hot curing water introduced into the
inflation bladder in much the same manner as the recirculation line
tied to the end of the everting bladder to cause the resin in the
impregnated layer to cure.
[0009] After the resin in the liner cures, the- inflation bladder
may be removed or left in place in the cured liner. Both the
pull-in and inflate method as well as the eversion method typically
require man-access to restricted manhole space on several occasions
during the process. For example, man-access is required to secure
the everting liner or bladder to the end of the elbow and insert it
into the collapsed liner.
[0010] Regardless of how the liner is to be installed a curable
thermosetting resin is impregnated into the resin absorbent layers
of a liner by a process referred to as "wet out." The wet-out
process generally involves injecting resin into resin absorbent
layers through an end or an opening formed in the outer impermeable
film, drawing a vacuum and passing the impregnated liner through
nip rollers as is well known in the lining art. A wide variety of
resins may be used, such as polyester, vinyl esters, epoxy resins
and the like, which may be modified as desired. It is preferable to
utilize a resin which is relatively stable at room temperature, but
which cures readily when heated with air, steam or hot water, or
subjected to appropriate radiation, such as ultra-violet light.
[0011] One such procedure for wetting out a liner by vacuum
impregnation is described in Insituform U.S. Pat. No. 4,366,012.
When the liner has inner and outer impermeable layers, the tubular
liner may be supplied flat and slits formed on opposite sides of
the flattened liner and resin injected and on both sides as
described in the '063 Patent. Another apparatus for wetting out at
the time of installation while drawing a vacuum at the trailing end
of the liner is shown in U.S. Pat. No. 4,182,262. The contents of
each of these patents are incorporated herein by reference.
[0012] Recent efforts have been made to modify the pull-in and
inflate method to utilize air to evert a bladder into the pulled-in
liner from a proximal access point. When the everting bladder
reaches the distal access point, steam is introduced into the
proximal access point to initiate cure of the resin impregnated
layer. This process offers the advantage of faster cure due to the
increased energy carried by the steam as the curing fluid. However,
the process still requires eversion of a bladder into the pulled-in
impregnated liner. Efforts to avoid this step of everting the
bladder into the pulled-in liner include performing the eversion
step above ground. For example, in U.S. Pat. No. 6,270,289, the
process includes everting a calibration hose into a flat-lying
lining hose above ground prior to pulling the hose assembly into
the existing conduit. This process avoids the eversion below grade,
but is severely limited into the length of lining that can be laid
out above ground prior to pulling-in.
[0013] A further suggestion to avoid this eversion is to
manufacture a liner having an inner coating and an outer coating so
that a curing fluid can be introduced directly into a pulled-in
liner. The disadvantages here involves the difficulty faced when
trying to impregnate the resin impregnable material disposed
between the inner and outer impermeable coatings. The outer coating
remains essential for handling the impregnated liner and to allow
the liner to be pulled into the existing conduit and the inner
coating is desired to all for curing with the steam.
[0014] Notwithstanding the modifications to both the eversion and
pull-in and inflate trenchless rehabilitation methods, both
processes are labor intensive, require an eversion step and suffer
from the increased costs associated with this. Accordingly, it is
desirable to provide a method and apparatus for continuously
impregnating a cured in place liner that is to be wrapped with an
outer impermeable layer.
SUMMARY OF THE INVENTION
[0015] Generally speaking, in accordance with the invention, a
non-pressurized resin impregnation tower for impregnating a cured
in place liner suitable for pull-in and inflate rehabilitation of
existing pipelines is provided. The impregnation tower is
constructed to have a sufficient resin head to impregnate the resin
impregnable material passing therethrough. A continuous length of
the resin impregnable material in a tubular shape is pulled
directly over a roller at the top of the tower and pulled down
through the resin in tower and under a roller in the base of the
tower and then up through the tower to calibration rollers at the
top as it exits. The wet-out tube is then wrapped with an outer
resin impermeable layer and sealed. The outer layer may be simply
heat sealed using a thermal bond or taped. This outer seal merely
encapsulates the resin impregnated material but should have
sufficient strength to withstand handling and abrasion as the liner
is transported and then pulled into the existing conduit.
[0016] The resin impregnable material can be formed into a tube and
sealed in a variety of ways. This includes conventional heat
bonding and taping, sewing and taping or sealing with an extruded
material. In one embodiment, the liner may have an impermeable
layer on the inside that may be bonded to the impregnable material.
This liner may be formed about a forming device with the
impermeable layer on the outside, sealed in one of the conventional
manners and then everted continuously through the forming device.
The outer layer is now the resin absorbent layer or layers that are
impregnated and wrapped with an impermeable polymeric layer to
contain the resin and allow for storage and pulling the impregnated
liner into the existing conduit. The inner layer should be one that
is impermeable to and resistant to the high temperatures of the
curing fluid.
[0017] Accordingly, it is an object of the invention to provide an
improved method of cured-in-place rehabilitation of existing
pipelines.
[0018] Another object of the invention is to provide an improved
apparatus for impregnation of a liner for cured in place
rehabilitation of an existing pipeline.
[0019] A further object of the invention is to provide an apparatus
for impregnating a resin impregnable liner having an inner
impermeable layer suitable for trenchless rehabilitation of
existing pipelines.
[0020] Yet another object of the invention is to provide an
improved method of manufacture of a resin impregnated cured in
place liner having an outer impermeable coating or wrapping in
continuous lengths without use of vacuum.
[0021] Yet a further object of the invention is to provide a method
of impregnating a cured in place liner for pull-in and inflate
trenchless pipeline installation.
[0022] Still a further object of the invention is to provide a
method of manufacturing a resin impregnated cured in place liner
having an inner impermeable layer and an outer impermeable
wrapping.
[0023] Still another object of the invention is to provide a method
of manufacturing a resin impregnated cured in place liner having an
integral inner impermeable layer and an outer impermeable
wrapping.
[0024] Still other objects and advantages of the invention will in
part be obvious and will in part be apparent from the
specification.
[0025] The invention accordingly comprises the several steps and
the relation of one or more of such steps with respect to each of
the others, the apparatuses embodying features of construction,
combinations and arrangement of parts that are adapted to effect
such steps, and the products that possess the characteristics,
features, properties, and the relation of components, which are
exemplified in the following detailed disclosure, and the scope of
the invention will be indicated in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] For a fuller understanding of the invention, reference is
had to the following description taken in connection with the
accompanying drawing(s), in which:
[0027] FIG. 1 is a perspective view of a length of a typical resin
impregnable cured in place liner suitable for use in lining an
existing pipeline of the type generally in use today and well known
in the art;
[0028] FIG. 2 is a cross-section view of a cured in place liner
having inner and outer impermeable layers constructed and arranged
in accordance with the invention;
[0029] FIG. 3 is a schematic view of the apparatus used for
preparing the inner portion of the liner having an outer felt layer
with an inner high temperature polymeric layer used in connection
with preparation of the cured in place liner of FIG. 2;
[0030] FIG. 4 is a cross-sectional view showing the structure of
the inner portion of the liner produced by the apparatus of FIG. 3
before being impregnated in accordance with the invention;
[0031] FIG. 5 is a schematic in elevation showing a resin
impregnation tower and tube sealing and wrapping apparatus for
applying an outer impermeable layer constructed and arranged in
accordance with the invention;
[0032] FIG. 6 is a cross-section of the edge sealer in the tube
sealing and wrapping apparatus taken along line 6-6 of FIG. 5;
[0033] FIG. 7 is a cross-sectional view of the impregnated liner
prepared by the apparatus of FIG. 5; and
[0034] FIG. 8 is a schematic in elevation showing wrapping of the
tubular member exiting a resin impregnation apparatus with an outer
coating by passing the wet out liner through a tube stuffer having
a tubular wrapping stored thereon; and
[0035] FIG. 9 is a cross-section of the liner prepared by the
apparatus of FIG. 8.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] A resin impregnated cured in place liner prepared in
accordance with the invention has an inner and outer impermeable
lining so that it can be installed by the pull-in-and-inflate
method and inflated and cured with a heated fluid without the use
of an inflation bladder. The liner has inner and outer impermeable
polymer coatings or layers and is prepared in continuous lengths.
It is impregnated without use of vacuum as it is assembled in view
of the increased effort necessary to impregnate a flattened liner
having a resin absorbent material between an inner and an outer
impermeable layer using convention vacuum impregnation
technology.
[0037] This increased effort is evidenced by the process suggested
in U.S. Pat. No. 6,270,289. Here, above ground a calibration hose
is inverted into a flat-lying impregnated lining hose, or an
impregnated lining hose is inverted into a tubular film using
compressed air. In this case, the length of the lining hose
approximates the length of the underground conduit to be lined. The
inversion of one tube inside the other requires an unobstructed
length equal to the length of the longest layer. If the two layers
had not been previously impregnated, it would be necessary to
inject resin between the layers on both sides of the lay flat tubes
in order to provide adequate impregnation. This is a difficult and
inefficient way to impregnate lining tubes. Thus, not only is the
length restricted, but also the impregnation is extremely
difficult.
[0038] FIG. 1 illustrates a flexible cured in place liner 11 of the
type generally in use today and well known in the art. Liner 11 is
formed from at least one layer of a flexible resin impregnable
material, such as a felt layer 12 having an outer impermeable
polymer film layer 13. Felt layer 12 and outer polymer layer 13 are
stitched along a seam line 14 to form a tubular liner. A compatible
thermoplastic film in a form of a tape or extruded material 16 is
placed on or extruded over seam line 14 in order to ensure the
impermeability of liner 11. In the embodiment illustrated in FIG. 1
and used throughout this description, liner 11 includes an inner
tube of a second felt layer 17 also stitched along a seam line 18
positioned at a point in the tube other than the location of seam
line 14 in outer felt layer 12. Outer felt layer 12 with polymer
layer 13 is then formed around inner tubular layer 17. After
impregnation liner 11 in a continuous length is stored in a
refrigeration unit to suppress premature cure of the resin. Liner
11 is then cut to a desired length after being pulled into the
existing pipeline, or is cut prior to being everted into the
existing pipeline.
[0039] Liner 11 of the type illustrated in FIG. 1 is impermeable to
water and air. This will allow use in an air or water eversion as
described above. However, in a pull in and inflate installation in
accordance with the invention, the outer coating on the liner need
only be sufficiently impermeable to allow for easy handling and
retention of resin and to prevent damage to the liner as it is
pulled into the existing pipeline.
[0040] For larger liner diameters, several layers of felt or resin
impregnable material may be used. Felt layers 12 and 17 may be
natural or synthetic flexible resin absorbable material, such as
polyester, acrylic, polypropylene, or inorganic fibers such as
glass and carbon. Alternatively, the resin absorbent material may
be a foam. Impermeable coating 13 on outer impregnable layer 12 may
be a polyolefin, such as polyethylene or polypropylene, a vinyl
polymer, such as polyvinyl chloride, or a polyurethane as is well
known in the art. Any form of sewing, adhesive bonding or flame
bonding, or any other convenient means can be used to join the
material into tubes. In the initial step in all trenchless
rehabilitation installations, the existing pipeline is prepared by
cleaning and videotaping.
[0041] Referring now to FIG. 2, a cured in place liner 21 prepared
in accordance with the invention is shown in cross-section. Liner
21 is constructed in similar fashion to convention liner 11, but
includes an inner tubular member with an inner impermeable layer 22
that has a thin felt or resin impregnable layer 23 bonded thereto.
Inner felt layer 23 with impermeable layer 22 has been sewn along a
seam line 24 by a row of stitches 26 and sealed with a tape 27
applied over stitches 26. An outer felt layer 28 is wrapped about
inner thin felt layer 23 and formed into a tube by stitches 29.
Finally, an outer layer or wrapping 31 is disposed about outer felt
layer 28.
[0042] By providing a liner having both inner and outer impermeable
layers, it is not necessary to evert the liner during installation
or evert an inflation bladder after the liner has been pulled into
the existing conduit. Thus, significant saving in labor cost at the
time of installation are available. It also allows for use of a
heated curing fluid such as steam to cure the resin. In such case
all the heated fluids are introduced into the liner below ground
level to provide a safer work environment.
[0043] Felt layers 23 and 28 may be impregnated in the usual manner
using vacuum. Alternatively, felt layers 23 and 28 are first
impregnated with resin and then an outer impermeable wrapping 31 is
applied. This avoids the difficulty with impregnating a finished
liner having felt layers between an inner and outer impermeable
layer. In U.S. Pat. No. 4,009,063, Eric Wood proposed injecting
resin in the felt layer using needles inserted into opposite sides
of a flattened constructed liner. This operation requires cutting
and patching needle holes in the outer coating. The vacuum
impregnation process taught in U.S. Pat. No. 4,366,012 would not be
suitable unless the vacuum is drawn on both sides as the inner
coating is a barrier to resin flow in a liner with inner and outer
coating. In order to overcome these impregnation difficulties,
liner 21 is manufactured from endless rolls of flat coated felt and
plain felt and continuously impregnated prior to application of
outer wrapping 31.
[0044] While felt layers 23 and 28 in FIG. 2 are formed into tubes
by stitching and/or taping, any of the conventionally known methods
for forming felt or other resin impregnable material into tubes is
suitable. For example, tubes can be formed by use of various glues
or adhesives as well as flame bonding. Tape may be applied to inner
impermeable layer 22 on inner felt layer 23 by applying an adhesive
strip or extruding a layer of polymeric material in order to seal
the butted edges of the felt material and the holes formed during a
sewing operation.
[0045] Referring now to FIG. 3, a method for continuously forming a
length of a tube of resin impregnable material with a sealed inner
layer of impermeable material is shown. A roll of coated felt 36
having an endless length of felt 37 with an impermeable layer 38 is
fed over a directional roller 39 in flat form with coated side
facing roller 39, to a tube-forming device 41.
[0046] Tube forming device 41 includes a tubular support frame 42
and a seaming device 43 that may be a sewing and taping machine,
gluing machine or flame bonding apparatus. Felt 37 with impermeable
layer 38 facing roller 39 is fed in the direction of an arrow A to
the proximal end of tube forming device 41 where it is wrapped
around support frame 42 and seamed into a tube 44 along a seam line
46 with felt 37 on the inside and impermeable layer 38 on the
outside. Tube 44 then passes a taping device 47 where a tape 48 is
placed over seam line 46 to form an impermeable coated taped tube
member 45.
[0047] Taped tube member 45 then continues to travel along tubular
support frame 42 to an inverter ring 49 at the distal end of
support frame 42. Taped tube member 45 is then everted into tubular
support frame 42 so that impermeable layer 38 is now on the inside
of tube 45 as it is withdrawn from the proximal end of tubular
support frame 42 along a line defined by an arrow B. At this point
everted tube 45 has the structure illustrated in cross-section in
FIG. 4 with impermeable layer 38 on the inside of tube 45 and felt
layer 37 on the outside. Tube 45 then continues to travel in the
direction of arrow B for the addition of one or more plain felt
layers. Tube 45 is then stored for further use, wrapped with an
outer impermeable coating, or may be passed directly to a resin
impregnation step as shown on FIG. 5 prior to final wrapping.
[0048] FIG. 5 illustrates in schematic the impregnation of a supply
51 of tubular member 45. Here, tube 45 is pulled by a pair of
rubber covered pulling rollers 52 and 53 into an open top resin
tower 54 filled to a predetermined level with a curable thermoset
resin 57 to form an impregnated or wet-out tube 55. Tube 45 passes
over roller 53 and down the full height of tower 54 to a bottom
roller 59 that turns tube 45 in an upward direction to a pair of
compression rollers 61 and 62. Tower 54 is about six to fourteen
feet in height, but can be any height sufficient to provide a
pressure head sufficient to wet out and impregnate the impregnable
layer of tube 45. The height necessary to provide sufficient head
to impregnate the impregnable material is dependent on the
viscosity of the resin, the thickness of the impregnable material
and the speed of feed through the tower. At this time, impregnated
tube 55 exiting tower 54 is ready for final wrapping with an outer
impermeable coating.
[0049] At this time impregnated tube 55 exiting open top tower 54
in the direction of an arrow D is fed into inlet end 68a of forming
pipe 64 in the direction of an arrow D' and is enveloped by
everting film tube 72. As film tube 72 is everted, edge seal 73 is
displaced to the inside of tube 72 so that edge seal 73 is disposed
between impregnated tube 55 and film tube 72. A wrapped wet-out
tube 74 including wet-out tube 55 and everted film tube 72 is
pulled out outlet end 64b of former pipe 64 and fed to a
refrigerated truck for storage and shipment to an installation
site.
[0050] Also illustrated in FIG. 5 is a film wrapping and sealing
station 63 that includes a former pipe 64 having an inlet end 64a
and an outlet end 64b and an edge sealer 65 positioned above the
mid-section of former pipe 64. A roll 66 of a resin impermeable
film material 67 that is to be wrapped about impregnated tube 55 as
it is fed into former pipe 64. Resin impermeable film material 67
is fed from roll 66 about a series of direction rollers 68a-e and
pulled by a pair of drive rollers 69a and 69b as film 67 is fed
over rollers 70a-d to a former pipe 64. A deflector 71 at outlet
end 64b directs film 67 about former pipe 64 prior to being fed
into edge sealer 65 to form film 66 into a tube 72 with an edge
seal 73 extending outwardly therefrom. Tube 72 of impermeable
material moving along former pipe 64 is pulled in a direction
indicated by an arrow E to inlet end 64a of former pipe 64
whereupon tube 72 is continuously everted into the interior of
former pipe 64 and onto impregnated tube 55 and pulled in the
opposite direction indicated by a dashed arrow F.
[0051] Referring to FIG. 7, a cross-sectional view through sealer
65 and former pipe 64 along line 6-6 in FIG. 5 is shown. Sealer 65
forms edge seal 73 in film tube 72 as film tube 72 passes over the
outside of former pipe 64. Once tube 72 is everted, edge seal 73 is
now inside wrapped wet-out tube 74 as it is pulled from outlet end
64b of former pipe 68. Outer impermeable film 72 may be applied
prior to or after wet-out. In the case where this is prior to wet
out, tube 45 prepared as shown in FIG. 3 is fed directly to tube
forming assembly 63 in FIG. 5 and provides liner 74 shown in
cross-section in FIG. 7. In this case resin impregnable material 37
is not impregnated.
[0052] Referring now to FIG. 8 an alternative apparatus for
wrapping an outer impermeable tube 81 about impregnated tube 55 is
shown generally as 82. Here tube 45 may be impregnated in the same
manner as described in connection with wet-out tower 54 in FIG. 5
and then tube 55 is fed into a stuffer pipe 83 having an inlet end
83a and an outlet end 83b. Reference numerals as used in FIG. 5 are
applied to identical elements here.
[0053] A supply of a flexible impermeable tube 81 is loaded onto
the outside surface of stuffer pipe 83 having an inlet end 83a and
an outlet end 83b. Impregnated tube 55 leaving resin tower 54 is
fed into inlet end 83a of stuffer pipe 83. As tube 55 enters inlet
end 83a of stuffer pipe 83, impermeable tube 81 is pulled off the
outside of stuffer pipe 83 and everted about inlet end 83a into the
inside of stuffer pipe 83 to envelope impregnated tube 55 as it
leaves outlet end 83b. This forms a complete liner 86 having inner
impermeable layer 38 and outer impermeable coating 81. Tube 86 with
outer coating 81 is removed from outlet end 83b of stuffer tube 83
by a pair of drive rollers 87 and 88, or other pulling device such
as tractors, in a direction of an arrow F. When an extruded tube is
used in this embodiment, there is no seam in outer impermeable
coating 81. The sole limitation of preparing tube 86 in this manner
is the length of impermeable tube 81 that can be placed on stuffer
tube 83. It has been found that about 1,000 feet of an impermeable
tube can be compressed onto a stuffer tube of about 20 feet in
length. Longer lengths can be stored on longer stuffer tubes.
[0054] FIG. 9 is cross-section of liner 86 as it exits stuffer tube
83. Liner 86 includes inner tubular member of resin absorbent
material 37 having an impermeable inner coating 38 sealed with a
tape 48 as described in connection with FIG. 4. After exiting
stuffer tube 83, liner 86 includes outer tubular wrapping 81. In
view of the fact that tubular wrapping 81 is a previously extruded
tube, outer wrapping 81 does not have any seams as in connection
with FIGS. 6 and 8.
[0055] Once at the installation site, impregnated tube 74 or 86
having inner impermeable layer 38 and outer impermeable wrapping 72
is ready for installation by the pull-in-and-inflate method. This
method is fully described in U.S. Pat. No. 4,009,063, the contents
of which are incorporated herein by reference. In the case of
installation by the pull-in-and-inflate method of impregnated liner
74, a separate eversion bladder is not necessary to inflate the
liner due to the presence of inner impermeable layer 38. By proper
selection of materials for inner impermeable layer 38, such as
polypropylene, curing can be done with steam introduced into the
liner 74 or 86 once in position in the existing conduit.
[0056] When the liner does not have inner impermeable layer 38, and
is wrapped with outer impermeable wrapping 72, installation may be
done by the conventional eversion method as described in U.S. Pat.
No. 4,064,211. Alternatively, such a liner may also be installed
using an inflation bladder as described in U.S. Pat. No. 6,539,979
B1 and U.S. Pat. No. 6,708,728 B2, the contents of which are
incorporated herein by reference as discussed therein, after the
resin in the liner cures, the inflation bladder may be removed or
left in place in the cured liner. If the inflation bladder is to be
left in place, the bladder will generally be one that has a
relatively thin resin impregnable layer on the inside of the
impermeable outer layer. In this case, the impregnable layer after
eversion will cause the bladder to adhere to the resin impregnable
layer of the liner as is well known in the art.
[0057] The processes and apparatuses described herein provide a
convenient means to prepare a cured in place liner having both
inner and outer impermeable layers. An impregnation tower as
illustrated in FIG. 5 readily provides a method to impregnate a
resin impregnable tube having an inner impermeable layer before an
outer impermeable layer is applied.
[0058] The tube prepared in apparatus shown in FIG. 5 avoids the
need to impregnate utilizing vacuum or high pressure techniques
which are cumbersome to use in view of the desire to impregnate in
a continuous fashion.
[0059] It will thus be seen that the objects set forth above, among
those made apparent from the preceding description, are efficiently
attained and, since certain changes may be made in carrying out the
above process, in the described product, and in the construction(s)
set forth without departing from the spirit and scope of the
invention, it is intended that all matter contained in the above
description and shown in the accompanying drawing(s) shall be
interpreted as illustrative and not in a limiting sense.
[0060] It is also to be understood that the following claims are
intended to cover all of the generic and specific features of the
invention herein described and all statements of the scope of the
invention which, as a matter of language, might be said to fall
therebetween.
* * * * *