PIPE LINING METHOD

METHODE DE REVETEMENT DE LA PAROI INTERIEURE D'UNE CONDUITE

English Abstract

THE INVENTION provides a method of lining a pipe
comprising the steps of positioning a mandrel in
co-axial relationship within the tube to extend
from end to end, charging the space between the
mandrel and the inner wall of the pipe with a
lining material having the required physical
properties, introducing a settable binder into the
aforesaid space to bind the lining material into a
continuous coherent lining, and removing the
mandrel once the binder has substantially set.

Claims

Page 11
CLAIMS
1. A method of lining a pipe characterized in
the steps of positioning a mandrel in
co-axial relationship within the tube to
extend from end to end, charging the space
between the mandrel and the inner wall of the
pipe with a particulate lining material
having the required physical properties,
introducing a settable binder into the
aforesaid space to bind the particulate
lining material into a continuous coherent
lining, and removing the mandrel once the
binder has set.
2. The method according to claim 1 characterized
in that the pipe is positioned generally
vertically and the binder introduced at low
level and allowed to filter upwardly through
the lining material substantially to fill the
space between the mandrel and the inner
surface of the pipe.

Page 12
3. The method according to claim 1
characterized in the step of sealing the
space between the mandrel and the inner
surface of the pipe and evacuating air from
such space during or prior to introducing
the binder into the space.
4. The method according to claim 1
characterized in that the lining material
is or includes a particulate material.
5. The method according to claim 1
characterized in that the binder comprises
a synthetic resinous binder.
6. The method according to claim 1
characterized in that the step of providing
a release agent or layer at the interface
between the lining and the pipe to permit
relative longitudinal movement between the
surfaces in use.

Page 13
7. The method according to claim 1,
characterized in the step of lining or
coating the mandrel with a release agent or
lining to prevent binding between the
mandrel and lining.
8. The method according to claim 7
characterized in that the mandrel is
sheathed in a tube of non-adherent material
such as polyethylene.
9. The method according to claim 1
characterized in that the mandrel is of a
tubular structure and adapted to be shrunk
or collapsed after the binder has set.
10. The method according to claim 1
characterized in that the mandrel is
adapted to be shrunk to permit removal
thereof once the binder has set and is of a
tubular structure and the method includes
the step of introducing a coolant such as
liquid nitrogen into the mandrel to effect
shrinkage thereof.

Page 14
11. The method according to claim 1
characterized in that the mandrel is
adapted to be collapsed for removal
purposes after the binder has set, and the
method includes the step of inflating the
mandrel prior to introducing the lining
material and/or binder and subsequently
deflating the mandrel to permit removal
thereof from the pipe.
12. Apparatus adapted for use in the method
claimed in any one of claims 1 to 11
characterized in an end cap construction
which comprises a crown formation adapted
to close the end of a pipe or the like,
first locating means adapted to locate the
end of the pipe relative to the crown
formation, and second locating means
adapted to locate a mandrel disposed within
the pipe relative to the crown formation.
13. Apparatus according to claim 12
characterized in that the construction
includes seal means adapted to seal the
space between the outer surface of the
mandrel and the inner surface of the pipe,
relative to the crown formation.

page 15
14. Apparatus according to claim 12
characterized in that the crown formation
defines one or more passageways through
which a binder and/or particulate lining
material may be introduced and/or air
evacuated into or from the space between
the mandrel and the inner pipe surface.
15. Apparatus according to claim 14
characterized in that the crown formation
provides a first passageway through which a
binder may be introduced or air evacuated,
and a end cap removably mounted on the
crown formation and which optionally
defines a second passageway through which
particulate material may be introduced into
the space between the mandrel and inner
pipe surface.
16. Apparatus according to claim 12
characterized in that the first locating
means is in the nature of a circumferential
recess adapted to receive the end of a pipe
together with a flange which may be defined
at the end of the pipe.

Page 16
17. Apparatus according to claim 12
characterized in that the second locating
means is in the nature of an aperture
through which a fastener may pass to engage
the mandrel.
18. A pipe lined in accordance with the method
claimed in any one of claims 1 to 11.

Description

PxI'>; (.:f.N:CNG IH);'i"tiOD o~~.,~.i~,.'~m~~
FIELD OF INVENTION
THIS invention relates to a method of lining the
interior of a pipe or the like.
DESCRIPTION OF PRIOR ART
Various wear resistant linings for steel pipes have
been proposed in the past, but these all suffer
from one disadvantage or another. For example it
is known to load tubular ceramic sections into a
pipe as a lining. The disadvantage of such an
arrangement is that corrosion and deterioration of
the steel pipe occurs at the junction between
adjacent ceramic sections. The ceramic sections
are moreover a costly commodity.
S~1MMARY OF INVENTION
According to the invention a method of lining a
pipe comprises the steps of positioning a mandrel
i n co-axi al rel ati onshi p wi thi n the tube to extend
from end to end, charging the space between the
mandrel and the inner wail of the pipe with a

Page 2
lining material having the required physical
properties, and introducing a settable binder into
the aforesaid space to bind the lining material
into a continuous coherent lining, and removing the
mandrel.
In a preferred arrangement the binder will be
introduced at low level, and allowed to filter
upwardly through the lining material substantially
to fill the aforesaid space. With such an
arrangement the pipe will preferably be positioned
generally vertically, a.nd the binder introduced at
the bottom end of the pipe. Preferably also the
method will include the step of sealing the space
between the mandril and the inner surface of the
pipe, and evacuating air from such space during or
prior to introducing the binder into the space.
Further according to the invention the binding
material is or includes a particulate material and
the binder preferably comprises a synthetic
resinous binder.
Still further according to the invention the method

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Page 3
includes the step of providing a release agent or
layer bet~~reen the outer surface of the lining and
the inner surface of the pipe to permit relative
longitudinal movement between these surfaces.
Further features of the invention provide for the
mandrel to be lined or coated with a non-adherent
release layer prior to the introduction of the
binder. Thus for example the mandrel could be
sheathed in a tube of suitable non-adherent
material such as polyethylene. The invention
further envisages that the mandrel could be of
tubular structure and adapted to be shrunk or
collapsed after the binder has set. Where the
mandrel is to be shrunk, it could for example be of
metallic material and shrun'< by means of the
introduction of a coolant such as liquid nitrogen
thereinto. Alternatively, the mandrel could be of
flexible material and be inflated and subsequently
deflated upon removal from the pipe.
Also included within the scope of the invention, is
apparatus adapted For use in the method disclosed
herein, such apparatus including an end cap

Page 4
construction which comprises a crown formation
adapted to close the end of a pipe or the like,
rr"first locating means adapted to locate the end of
the pipe relative to the crown formation, and
second locating means adapted to locate a mandrel
disposed within the pipe relative to the craven
formation. In one embodiment of the invention the
construction will also include seal means adapted
to seal the space between the outer surface of the
mandrel and the inner surface of the pipe, relative
to the crown formation. With such an arrangement
the invention of the crown formation defines a
passageway through which a binder may be
introduced, and/or air evacuated, into or from the
space between the mandrel and the inner pipe
surface.
Preferably the first locating means will be in the
nature of a circumferential recess adapted to
receive the end of 'the pipe and any flange which
may be defined at the end of the pipe. The second
locating means could be in the nature of an
aperture through which a fastener may pass to
engage the mandrel. Doubtless many variations are
possible in this regard.

C~~~~~
Page 5
The invention also includes within its scope the
provision of a second end cap construction which
comprises a crown forrnation adapted to close the
end of a pi pe or the 1 i ke, a f i rst 1 ocati ng means
adapted to locate the end of the pipe relative to
the crown formation, second locating means adapted
to locate a mandrel disposed within the pipe
relative to the crown formation, and apertures in
the crown formation through which particulate
material may be charged into the space between the
outer surface of the mandrel and the inner surface
of the pipe.
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-B-R~-~~ DESCRIPTION OF PREFERRED EMBODIP1ENT
Further features of the invention will appear from
the embodiment described below purely by way of
example with reference to the accompanying drawings
wherein:
Figure 1 is a partially sectioned perspective
view of a pipe which is in the
process of_ being lined in accordance
with method of the invention; and

Page 6
Figure 2 is a sectioned elevation of the pipe
in Figure 1 shown during a resin
filling operation.
In one example of the invention a method of lining
a pipe 10 with a wear resistant lining comprises
the steps of locating a mandrel 11 co-axially
within the bore of the pipe 10 and charging the
space 12 between the outer surface of the mandrel
and the inner surface of the pipe with a
particulate wear resistant material 13 such as
alumina. The particulate lining material is
thereafter bound into a continuous coherent lining
as described in more detail below.
The mandrel 10 is held in a central position within
the pipe by means of end cap constructions 14 or
15. The construction 14 defines a crown formation
including an outer closure 14a which encloses the
end of the pipe, a first locating formation in the
form of a groove 14b which is adapted to receive
the end 10a of the pipe 10, a flange 14b therefore,
and a second locating formation 14c also in the
form of a recess adapted to receive the mandrel 11.

r
Page 7
The end cap construction 14 further includes a pair
of seal ri ngs 15 and 16, the seal ri ngs 15 and 16
being adapted to seal the pipe flange lOb and the
mandrel 11 respectively relative to the crown
formation 14 thus in effect sealing the space 13
between the outer surface of the mandrel and the
inner surface of the pipe.
a different end cap 17 for facilitating the
charging of particulate material 13 into the space
12 between the mandrel 11 and the inner wall of the
pipe 10 is shown in Figure 1. This end cap 17
dispenses with the seals 15, 16, and defines
elongated slots 17b in its outer closure 17a to
align with the space I2 between the mandrel 11 and
the inner pipe surface. Once the pipe 10 has been
charged with the particulate lining material 13,
the end cap 15 shown in Figure 1 can be removed and
the end cap 14 shown in Figure 2 is employed to
seal the space 12 between the mandrel 11 and the
inner surface of the pipe 10.
The method of the invention further provides that a
layer 18, preferably a tube of release material

Page 8
will be located on the outer surface of the mandrel
11. By release material is meant material which
will not adhere to the binder which is described in
more detail below. Preferably a sleeve 18 of
polyethylene or the like material will be drawn
over the mandrel 11 and additionally a coating of
release agent, not shown, will be applied to the
outer surface of the polyethylene material.
The method of the inventiol1 farther provides that a
coating or layer 19 of release material will also
be provided on the inner surface of the pipe 10 to
prevent the lining which is formed by the, method
from binding to the wall and thus being subjected
to stress as a result of the expansion or
contraction of the pipe. Such a lining could
likewise be in the form of a tubular sleeve of
polyethylene or the like material or could simply
comprise a coating of release agent.
Once the particulate lining material 13 has been
charged into the space 12 between the outer surface
of the mandrel and the inner surface of the pipe,
this space is sealed as desc;~ibed above, and a

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Page 9
binder 20 is then introduced into the space 12 to
b i nd the parti cul ate materi al 13 i nto a conti nuous
coherent lining. The method of the invention
provides that the pipe i0 will be generally
vertically orientated and the binder 20 introduced
into the space 12 at low level through a port 14d
in the end cap construction 14 and allowed to
filter upwardly through the particulate material
13, Figure 2. For most applications a liquid
settable synthetic resinous mater9al such as a
polyester or epoxy resin having the required
properties will be used. In order to facilitate
the resin filling process, the method of the
invention provides for air to be evacuated from the
space 12 between the mandrel and the inner surface
of the pipe, at high level through the port 14d at
the upper end cap construction 14, Figure 2. It
has been found that the evacuation of air has a
further beneficial effect of largely eliminating
formation of foam or bubbles which could result in
void areas in the lining. Means for injecting the
resin 20 into the lining zone 12 will preferably be
in the form of conventional high pressure resin
pumping equipment which will preferably include
means for mixing the resin with the required
polymerization catalyst.

Page 10
Once the resin has set the end caps and the mandrel
wi 11 be removed f rom the pi pe 1 eavi ng a conti nuous
coherent lining within the pipe 10. In order to
facilitate removal of the mandrel, the mandrel
could be of tubular construction of a suitable
metal, and a coolant could be introduced into the
bore of the tube to shrink the tube and thus to
permit ready extraction of the mandrel.
Alternatively, the mandrel could be in the nature
of a collapsible tube of rubber or synthetic
resinous material which is adapted to be inflated
until the resin has set and thereafter to be
deflated and extracted from the pipe. Clearly
other variations are also possible and it is
envisaged that these will all Fall within the scope
of the consistory clauses. ror example, in one
arrangement the end cap construction 14 could
define a formation which projects a short distance
into the tube so that the lining is moulded into a
particular Form at the ends of the pipe, for
example an outwardly diverging form.

Representative Drawing