Note: Descriptions are shown in the official language in which they were submitted.
- 1 -
"Method for repairing or reclaiming, in situ,
a section of a pipeline or container intended to
contain or containing a fluid under pressure
and device for implementing this method"
The present invention relates to a method for
repairing or reclaiming, in situ, a section of a pipeline
or container intended to contain or containing a fluid
under pressure.
The present invention also relates to a device
for implementing this method.
Various methods are known for repairing or
reclaiming, in situ, a section having a fault of any
origin or nature whatsoever, corrosion, fissure, removal
of material, through hole, with or without deformation,
etc., on a pipeline or container intended to receive a
fluid under pressure.
It is thus known, for example, after, if
appropriate, having repaired the actual fault and re-
established the outline of the pipeline or container, how
to prepare and assembly solidly to each other and onto
the latter two half-shells designed for restoring the
strength and leaktightness of this pipeline or container.
Such an operation is laborious and delicate when it is
carried out at the ground surface; it is all the more so
if a pipeline or container laid or buried on the seabed
is involved.
Moreover, various methods are known for
externally and uniformly reinforcing tube elements or
cylindrical containers, generally made from steel, before
installing or mounting them.
According to these methods, the tube elements or
the individual containers are made to revolve on them-
selves before being assembled, and high-strength steel
wires or tapes or flexible strips are wound around the
entire peripheral surface of the latter, with or without
tension, in order to increase the strength of the tubes
or of the containers with respect to the internal
CA 02092690 2000-O1-17
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2
pressure and/or their resistance to centrifugal forces.
The object of all these methods is to produce
pipelines or containers capable of withstanding increased
internal pressure: or, :Eor the same pressure, of reducing the
thickness of meta7_ necessary with the purpose of lightening the
latter.
In accordance with the present invention, there is
provided a method for respairing a fault in a hollow tubular
member adapted to contain a fluid under pressure, comprising
the following steps: (a) securing to a hollow tubular member
having a fault to be repaired, adjacent said fault, one end of
a flexible tape consisting of continuous longitudinal fibers
that occupy from ?.0-60% of the cross section of the tape, said
fibers being enca~;ed in a matrix composed of material selected
from the group consisting of thermoplastic and metal, the
elastic limit of the material of the fibers being greater than
the elastic limit of thE: material of the tubular member; (b)
unwinding the tape from a coiled supply of the tape that
revolves around tl-..e tubular member and is displaced axially
along the tubular member; (c) braking the tape between the
tubular member and. said coiled supply at a point that revolves
with said coiled supply and that is spaced from said coiled
supply thereby to impart: to the tape a substantially greater
tension between said point and said tubular member than between
said coiled supply and :>aid point; (d) heating the tape
immediately prior to applying it to the tubular member, in
order to make the thermoplastic material of the matrix melt
throughout its entire mass, and to provide conditions for
optimum adherence of the: tape to the tubular member or to a
previously laid-down tai>e covering said tubular member; and (e)
applying the tape to they tubular member or a previously laid
down tape covering said tubular member, in order to wind under
tension the tape around the tubular member in a helix and cover
CA 02092690 2000-O1-17
2$541-18
2a
said fault and to imparts to the tubular member by the tape a
predetermined pre:~tress;; the improvement comprising the
following additional steps: (f) cooling the tape immediately
following its application to the tubular member by applying to
the tape a blast of cold air, in order to resolidify the
thermoplastic matrix and to prevent migration of the fibers
through the thermoplastic matrix; and (g) creating on the
tubular member, on both sides of the repaired fault, transition
sections extending over a predetermined length and on which a
prestress is produced which decreases progressively when moving
away from the repaired :section, by reducing the tension of the
tape.
In accordance with the present invention, there is
further provided a.n apparatus for repairing a fault in a hollow
tubular member adapted t:o contain a fluid under pressure,
comprising: (a) means for securing to a hollow tubular member
having a fault to be repaired, adjacent said fault, one end of
a flexible tape consisting of continuous longitudinal fibers
that occupy from 30-60% of the cross section of the tape, said
fibers being encased in a matrix composed of material selected
from the group consisting of thermoplastic and metal, the
elastic limit of the material of the fibers being greater than
the elastic limit of the' material of the tubular member; (b)
means for unwinding the tape from a coiled supply of the tape
that revolves around the tubular member and is displaced
axially along the tubular member; (c) means for braking the
tape between the tubular member and said coiled supply at a
point that revolves with said coiled supply and that is spaced
from said coiled supply thereby to impart to the tape a
substantially greater tE:nsion between said point and said
tubular member than between said coiled supply and said point;
(d) means for heating the tape immediately prior to applying it
to the tubular merr~ber, in order to make the thermoplastic
CA 02092690 2000-O1-17
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2b
material of the matrix melt throughout its entire mass, and to
provide conditions for optimum adherence of the tape to the
tubular member or to a previously laid-down tape covering said
tubular member; and (e) means for applying the tape to the
tubular member or a previously laid-down tape covering said
tubular member, in order to wind under tension the tape around
the tubular member in a helix and cover said fault and to
impart to the tubular member by the tape a predetermined pre-
stress; the improvement comprising: (f) means for cooling the
tape immediately following its application to the tubular
member by applying to the tape a blast of cold air, in order to
resolidify the thermoplastic matrix and to prevent migration of
the fibers through the thermoplastic matrix; and (g) means for
creating on the tubular member, on both sides of the repaired
fault, transition sections extending over a predetermined
length and on which a px-estress is produced which decreases
progressively when moving away from the repaired section, by
reducing the tension of the tape.
In these: methods, a flexible strip is generally wound
around the hollow body in substantially adjoining turns, by
causing said hollow body to revolve upon itself and this strip
is fastened to the: hollow body. The strips used are made up of
a material whose elastic: limit is greater than that of the
material of said r.ollow body.
Accordir..g to one of these methods, during the winding
a slight tension is app7.ied to a strip made up of glass fibers
embedded in a synthetic resin. This method makes it possible
to obtain exceller..t protection against corrosion, the fibers
embedded in the synthetic resin being securely fastened to the
hollow body reinforced over its entire surface. The slight
tension applied implies, taking into account the difference
between the respective Elastic moduli of steel and of glass,
which are the materials most commonly used, a hydraulic
CA 02092690 2000-O1-17
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2c
expansion of the reinfo~__~ced hollow body in order to make use of
all the strength c>f the glass.
According to another method, a flexible tape is wound
with a sufficient tension so that, when the hollow body is
pressurized, the :>tresses likely to be exerted in the hollow
body and in the wi.nding:~ of said strip reach their maximum
permissible value at substantially the same time.
In all cases, the metal is prestressed uniformly over
the entire length of the pipeline or container so as to be
stressed permanently in substantially the same way at any point
on the latter under all conditions of use of the latter:
construction, tests at proof pressure, normal use. It is thus
possible to ensure that any stress gradient likely to lead to a
fatigue fracture c>f the metal is prevented.
2~9~6~~ _
- 3 -
These methods apply neither to a pipeline or
container which is already installed and in service, nor
to a localized implementation on site, at ground level or
on the seabed, on a section of such a pipeline or
container.
The object of the invention is to overcome the
drawbacks of the known methods and to propose a method of
the aforementioned type whose implementation is simple,
effective and economical at any point whatsoever in an
existing installation.
Another object of the invention is to propose a
device for implementing the method of the invention.
According to the invention, the method of the
aforementioned type is one which comprises the following
steps:
a) if necessary, any possible fault whatsoever in
said section is blocked off by means of a blocking-off
material;
b) the front end of a flexible strip of very high
longitudinal mechanical strength made up of continuous
longitudinal fibers representing, in cross section, from
to 60% of the cross section of the strip, coated in a
thermoplastic matrix, and whose elastic limit is greater
than that of the pipeline or container material, is fixed
25 with respect to the external peripheral surface of the
pipeline or container;
c) means for supplying the flexible strip are
made to revolve around the pipeline or container, and are
displaced axially along the latter, in a to-and-fro
30 movement, from one end of said section to the other and
beyond:
d) said flexible strip is wound around the
pipeline or container under tension following successive
crossed-over helixes with predetermined coiling angles,
at the point and in the vicinity of said section on
either side of the latter, heating said strip in order to
make the thermoplastic material of the matrix of the
strip melt throughout substantially its entire mass, just
2~~~~~~
- 4 -
before it is applied to said peripheral wall or to a
previously laid-down layer of said strip, and immediately
cooling said strip as soon as it is applied in order to
resolidify said matrix, and homogeneous layers are thus
built up over the entire surface of said section, then
the rear end of the strip is fastened with respect to
said pipeline or container;
e) the number of layers of the strip superposed
at the same point as well as the winding angles and
tension of the strip being sufficient to prestress the
material of the pipeline or container both radially and
longitudinally, and thus to restore predetermined
mechanical characteristics to said section of the
pipeline or container.
Thus, simply by winding a flexible strip under
tension around a section of an existing pipeline or
container having a fault, which flexible strip can
obviously be laid down in several layers, a localized
reinforcement having the desired strength may be produced
on this section.
The strip is thus laid down under tension in
successive crossed-over helixes with predetermined
coiling angles: the corresponding segments of the stxip
exert, on'the material of the section to be repaired, a
prestress which is both longitudinal and radial, making
it possible to more than compensate for the loss in
characteristics of said section brought about by the
fault to be repaired.
The fact that the thermoplastic material of the
matrix is melted throughout its entire mass means that
the aforementioned segments are deformed in the region of
the cross-overs in order completely and homogeneously to
cover the entire periphery of said section. Cooling is
then carried out as soon as the strip has been applied,
in order to prevent any migration of the fibers through
the heat=curable matrix.
The strip is thus coiled under the foreseen
tension which in turn brings about the aforementioned
. , ~09~~~~ _._
prestress without deterioration of the properties of the
strip.
The advantage of the present invention is
precisely to have overcome the precedent according to
which reinforcing a hollow body by prestressing said
hollow body by winding a flexible strip had necessarily
to be continuous and homogeneous in order not to
introduce, into the material of said hollow body, stress
gradients likely to weaken the strength of the latter,
and to have analyzed the problems posed by repairing a
fault in order to adapt to this operation the process of
winding a flexible strip.
It will be understood that the method of the
invention may be implemented easily in the field at any
point whatsoever of an existing installation on the
ground as on the seabed.
According to an advantageous version of the
invention, the strip is pressed onto the peripheral wall
of the pipeline or container as soon as it has been
applied to said wall or to a previously laid-down layer
of said strip.
Any bubble of air or gas trapped between the wall
of the pipeline or container and the various superposed
layers of strip is thus eliminated, and the material o~
the strip is made to flow slightly in order to obtain a
perfect join between two segments of tape in contact with
each other, so as to cover and reinforce completely and
homogeneously the wall of the pipeline or container and
to ensure perfect leaktightness, as well as excellent
protection against corrosion.
According to a preferred version of the
invention, winding is carried out so that the prestress
exerted on the material of the pipeline or container
decreases progressively from a predetermined point when
moving away from said repaired or reinforced section on
either side of the latter.
The local prestress gradient and therefore the
internal stresses due to this gradient are thus
- 6 -
decreased, so as to reduce the fatigue of the metal on
Bather side of the repaired or reinforced section.
According to another aspect of the invention, the
device for repairing or reclaiming, in situ, a section of
a pipeline or container intended to contain or containing
a fluid under pressure, according to the method in accor-
dance with the invention, is one which comprises:
- a chassis intended to bear on the pipeline or
container and/or on the ground,
- means for fastening the chassis to the pipeline
or container and centering it with respect to the latter,
- equipment which can move with respect to the
chassis and which is intended to revolve around the
pipeline or container;
- means for causing the moving equipment to
revolve with respect to the chassis around the pipeline
or container;
- the moving equipment comprising means which can
move axially to supply a flexible strip and means for
winding said flexible strip around the pipeline or
container under. tension following successive crossed-over
helixes with predetermined coiling angles when the moving
equipment revolves around said pipeline or container,
--means for heating said strip in order to make
the thermoplastic matrix of the strip melt throughout its
entire mass before said strip is applied, and means for
immediately cooling said strip as soon as it is applied
in order to resolidify said matrix.
Other characteristics and advantages of the
invention will emerge in the detailed description
hereafter.
In the appended drawings, given by way of non-
limiting examples:
- Figure 1 is a partial diagrammatic view from
above of a section of a pipeline having a fault to be
repaired;
- Figure 2 is a partial view in longitudinal
section of the pipeline of Figure 1, after repair, the
2~~~~~
-,-
fault not passing through the wall of the pipeline;
- Figure 3 is a view similar to Figure 2, the
fault passing through the wall of the pipeline;
- Figure 4 is a diagrammatic view illustrating
the sub-assembly for winding the flexible strip around
the pipeline;
- Figure 5 is a diagrammatic view in perspective
representing the implementation of a device according to
a first embodiment of the invention;
- Figure 6 is an enlarged view in perspective of
the device of the Figure 5;
- Figure 7 is another enlarged view in perspective
of another embodiment of the device in accordance with
the invention;
- Figure B is a view similar to Figure 6 of
another embodiment of the device of the invention;
- Figure 9 is a graph diagrammatically represen-
ting the possible movements, along five axes, of the
winding sub-assembly with respect to the carriage and the
chassis in another embodiment of the invention;
- Figure 10 is a diagrammatic front view of an
articulated fork of the chassis in position on a pipeline
whose diameter is the maximum diameter envisaged for this
fork;
- Figure 11 is a view similar to Figure 10, the
fork being in position on a pipeline whose diameter is
the minimum diameter envisaged for this fork.
Figure 1 represents a fault 1 on a pipeline 2
intended to contain or containing a fluid under pressure,
especially any pressurized gas whatsoever such as natural
gas for example, or any pressurized liquid whatsoever,
such as water, crude oil, a petroleum product, a heat
transfer liquid for example. Such pipelines are commonly
encountered in the natural gas and oil industry,
chemistry, the nuclear industry, the processing and
transportation of steam or hot water, for example. Such
a pipeline 2 is generally made from steel. It may be laid
on the ground or buried. It may be laid or buried on the
20~~6~~
_ g _
seabed or at the bottom of any stretch of water
whatsoever.
The fault 1 may be of any nature and origin
whatsoever. It may have been brought about by corrosion,
by metal fatigue, by a blunt external object. It may thus
involve a fissure, a removal of metal, a hole passing
through the wall of the pipeline. In these latter cases,
the edges of the fault may or may not be deformed. The
fault may be on the external face or on the internal face
of the pipeline 2.
Such a pipeline generally comprises a protection
coating, in particular a corrosion protection coating. A
sub-sea pipeline further comprises an external concrete
coating acting as ballast.
Before any repair of a fault, the pipeline is
previously relieved of its protection coating, surface-
treated, for example by sand blasting, trimming, brush-
ing, etc., then coated with a primary layer facilitating
the adherence of a reinforcement element, and also
ensuring protection against corrosion, all this being
carried out in~a manner known per se.
If necessary, the pipeline or container has dents
or bumps removed from the inside, for example by means of
a "pig" pushed by the pressure of the fluid inside this
pipeline or container in order to reestablish the initial
internal outline of the latter. Use may also be made of
any other known means such as thrust cylinders, jacks,
etc., especially if the edges of the fault are deformed
toward the outside of the pipeline.
In the case of a sub-sea pipeline, the removal of
the ballast and of the protection coating generally takes
place in the water, then all the repair operatians are
preferably carried out under a diving bell.
The invention in the case of pipeline will be
described below, it being specified that all that which
is to be described with reference to this pipeline may be
applied to any pressurized container whatsoever, which
does not necessarily have to be asymmetric. The
2~9~~'~~
g _
asymmetric shape is, however, preferred insofar as it
allows an even and homogeneous reinforcement, another
shape making it necessary to use additional safety
coefficients in order to compensate for the
irregularities and losses of homogeneity. It is also
assumed that said pipeline is made from steel, it being
clearly understood that the invention may be applied and
may easily be adapted to a pipeline or container made
from any material whatsoever, for example concrete.
The method of the invention may be implemented on
a pipeline or container in use or under pressure since
the section to be repaired or reclaimed does not comprise
any fault passing through the thickness of the latter.
This pipeline or container must have an external diameter
preferably greater than approximately 100 mm.
The method for reFairing or reclaiming, in situ,
a section of a pipeline intended to contain or containing
a fluid under pressure, is one which comprises the
following steps:
a) if necessary, any possible fault whatsoever in
said section is blocked off by means of a blocking-off
material;
b) the front end of a flexible strip of very high
longitudinal mechanical strength made up of continuous
longitudinal fibers representing, in cross section, from
to 60% of the cross section of the strip, coated in a
thermoplastic matrix, and whose elastic limit is greater
than that of the pipeline or container material, is fixed
with ~reapect to the external peripheral surface of the
30 pipeline or container;
c) means fox supplying the flexible strip are
made to revolve around the pipeline or container, and are
displaced axially along the latter, in a to-and-fro
movement, from one end of said section to the other and
beyond:
d) said flexible strip is wound around the
pipeline or container under tension following successive
crossed-over helixes with predetermined coiling angles,
....,
~~392~~~
- 10 -
at the point and in the vicinity of said section on
either side of the latter, heating said strip in order to
make the thermoplastic material of the matrix of the
strip melt throughout substantially its entire mass, just
before it is applied to said peripheral wall or to a
previously laid-down layer of said strip, and immediately
cooling~said strip as soon as it is applied in order to
resolidify said matrix, and homogeneous layers are thus
built up over the entire surface of said section;
e) the number of layers of the strip superposed
at the same point as well as the winding angles and
tension of the strip being sufficient to prestress the
material of the pipeline or container both radially and
longitudinally, and thus to restore predetermined
mechanical characteristics to said section of the
pipeline or container.
Preferably, these predetermined mechanical
characteristics are at least equal to those provided when
the pipeline was designed.
In a known fashion, after repairing and possibly
blocking off the fault (or faults), the conventional
operations of surfacing the repaired zone, and laying
down a primary coating serving both as a binding layer
and as anw anti-corrosion layer are carried out.
Winding is carried out so that the prestress
exerted on the material of the pipeline decreases pro-
gressively from a predetermined point when moving away
from said repaired or reclaimed section on either side of
the latter.
The blocking-off material may extend radially
outward with respect to the external peripheral surface
of the pipeline.
When the strip is applied to a previously laid
down layer, this layer is itself preferably superficially
mounted.
Finally, the strip is pressed onto the peripheral
wall of the pipeline as soon as it has been applied to
said wall or to a previously laid-down layer of said
s
- 11 -
strip.
The number of layers of the strip superposed at
the same point as well as the winding angles and tension
of the strip must be sufficient for the blocking-off
material and/or the material of said section of the
pipeline to be prestressed when the pressure of the fluid
inside -the latter is equal to the proof pressure.
However, the tape and especially the fibers of which it
is composed will only be subjected to a stress level such
that no perceptible relaxation arises during time. In the
- case of glass, the tension applied to the fibers will not
exceed approximately 40% of their breaking strength.
The various helical segments of strip may be
applied with one same coiling angle or with several
coiling angles, determined so as to ensure the desired
prestress both in the radial direction and in the
longitudinal direction.
Under these conditions, a state of compression or
prestress is maintained which makes it possible to
restore leaktightness and strength of the pipeline to the
internal pressure whilst protecting it from corrosion and
environmental aggressian.
Indeed, it is easily understood, and calculation
confirms it, that under such prestresa, a fissure of the
metal of the pipeline closes up and remains closed.
Likewise, a plug blocking a hole passing through, or
otherwise, the thickness of the pipeline is held in place
on the one hand by the various layers of tape and, on the
other- hand, compressed by the metal located at the
-periphery of the hole and subjected to this prestress.
Finally, for each layer, the adjoining turns connected to
one another by the superficial melting of the internal
face of the strip before laying down constitute a leak-
tight jacket.
It is thus possible locally to reinforce a
pipeline whose wall has been partially penetrated or even
pierced. .
---,
~09~6~fl
- 12 -
It is also possible to reinforce, even slightly,
over a great length, a pipeline which no longer has the
required guarantees of safety.
Finally, in order to ensure absolutely risk-free
S transition between the good pipeline, in which the stress
in use is tensile, and the repaired or reclaimed section,
in which the stress in use is generally compressive,
transition sections of a certain predetermined length, on
which a prestress is produced which decreases
progressively when moving away from the repaired or
reclaimed section, are produced on either side of the
actual section to be repaired. It is possible to
calculate the values of this prestress and the length
over which it decreases so that the internal stresses in
the metal in these transition sections remain within
levels which -the metal can withstand without the
slightest risk for the latter.
It should be noted that the excellent and rapid
adherence of the strip to the pipeline or to a previously
laid-down layer makes it possible easily to decrease the
winding tension at each of the ends of each segment of
strip laid down as a helix on each axial "to" or "fro"
movement of the winding means (see below).
In the case in which the section to be repaired
or reclaimed is contiguous with an accessory of the
pipeline such as a valve, reinforcement or the like, of
a thickness greater than that of the pipeline, the
transition may be produced by a winding fading out on
said accessory of greater thickness.
For this purpose, it is obviously possible to act
at the same time or independently on the number of layers
of the strip and the tension of the latter, which may
both decrease progressively when moving away from the
repaired or reclaimed section.
In the embodiments represented respectively in
Figures 2 and 3, the faults 1, one of which, Figure 3,
passes through the wall 3 of the pipeline 2 whilst the
other, Figure 2, does not pass through it, are blocked by
_-
- 13 -
a plug 4.
The plug 4 is produced from any known material
whatsoever°. this may be added metal laid down by electric
welding, for example. This may also be a plug made from
a synthetic resin or any other material compatible with
the metal of the pipeline 2.
The plug 4 is covered with three layers of
reinforcement 5a, 5b, 5c, which will be described later.
In the embodiment of Figure 4, a winding sub
assembly 42, mounted on moving equipment, not shown for
the clarity of the drawing, revolves around the pipeline
2, in the direction indicated by the arrow 6a, and is
displaced at the same time parallel to the pipeline 2
from left to right on the drawing in the direction of the
arrow 6b in order to lay down a second segment as a helix
lOb. This winding sub-assembly 42 has previously been
displaced from right to left on the drawing in order to
lay down a first segment as a helix 10a, which crosses
the segment lOb, the respective coiling angles of the
segments 10a, lOb being opposite. In the displacement to
the left, the sub-assembly 42 will lay down a new segment
which is offset with respect to the segment l0a and which
will cross the segment lOb.
As a variant, it would also be possible to lay
down a first homogeneous layer of parallel segments as a
helix, such as 10a, by coiling during the displacements
of the sub-assembly 42 in a single direction, then to lay
down a second homogeneous layer of parallel segments such
as lOb, by coiling during the sole displacements in the
other direction.
The winding sub-assembly 42 comprises:
- a braked spool 7 which revolves in the direc-
tion of the arrow 8 when the winding sub-assembly 42
revolves in the direction of the arrow 6a. The spool 7
carries a flexible strip 9 which is unwound from the
spool and is wound around the pipe 2 in order to form
consecutive crossed-over segments as a helix 10a, lOb;
- 14 -
- a set of two rollers 11, 12 between which the
flexible strip 9 is clamped and braked. These two rollers
are, for example, coated with teflon at their periphery;
they adjust the winding tension of the flexible strip 9;
- an angle guide 13, which defines the direction
in which the strip 9 is applied to the pipeline 2. The
angle guide 13 may be, for example, a small wheel or a
roll coated at its periphery with teflon, or any bar,
either fixed or revolving. The angle guide 13 has, at its
periphery, a concave groove which receives the strip 9
and the concavity of which is directed outward. The angle
guide 13 is particularly used to fit the winding sub-
assembly 42 to pipelines of various diameters.
- means 14 for heating and melting, throughout
substantially its entire mass, the thermoplastic material
of the matrix of the flexible strip 9 just before said
strip is applied to said peripheral wall of the pipeline
2 or a previously laid-down layer of strip, as well as
for heating said pipeline or layer: it involves, for
example, an electrical heating device or a blow torch
with a reducing flame, of the oxyacetylene type, if the
operation is to be carried out in the open air, or an
electrical heating device or a hot gas blow torch operat-
ing, if necessary, under a diving bell enclosing a gas,
which is preferably non-oxidizing, if the operation is to
be carried out submerged. The strip thus adheres very
well to said wall or layer.
- means 14a for cooling, if necessary, the strip
9 as -soon as it is applied, in order to resolidify the
thermoplastic matrix. It involves, for example, a blast
of cold air. It is understood that on a section of pipe
for transporting pressurized gas whose temperature is
-10°C for example, the use of cooling means is not
required.
- means 15 for measuring the temperature of the
point of the peripheral surface of the pipeline 2,
possibly already covered with one or several layers of
strip, onto which the strip is to be laid down, and means
_,.~
- 15 -
(not shown) for adjusting the heating power of the
heating means 14 as a function of the measured tempera-
ture so as to provide the conditions for optimum
adherence of the strip to said peripheral surface or to
the previously laid-down strip covering the latter. It
involves, for example, a temperature probe of any type
Whatsoever.
- means 16, for example a roller or a teflon
coated roll, both independent of the system for adjusting
LO the winding tension, for pressing the flexible strip 9
against the peripheral wall of the pipeline 2 just after
applying said strip 9 to said wall. This pressure causes
the material of the matrix to flow slightly, which joins
the adjacent turns to one another and ensures leaktight
neea of the pipeline.
It should be noted that the angle guide 13 may be
located either in the heating zone of the strip 9, or in
the cold zone located upstream of the heating zone with
respect to the direction of travel of the strip. The
angle guide 13 and the heating means 14 are adjustable so
as to be able to be matched to the winding conditions and
in particular to the diameter of the pipeline 2.
The speed of longitudinal displacement of the
sub-assembly 42 along the pipeline 2 is adjusted as a
function of the coiling angle which is to be obtained.
The flexible strip 9 of very high longitudinal
mechanical strength is made up of continuous longitudinal
fibers coated in a matrix. The matrix may be metal, for
example aluminum, the fibers being made, for example, of
steel. The matrix may also and preferably be made from a
thermoplastic synthetic resin, the fibers being, for
example, glass, carbon, aramid, etc. fibers. The fibers
are chosen so that the strip 9 has an elastic limit
greater than that of the steel of the pipeline Z. The
melting point and/or vitreous transition point of the
matrix used are, in all cases, at least 50 K less than
those of the fibers respectively. Use is generally made
of a strip in which the cross section of the fibers
2~9~,~~~
- 16 -
represents, in transverse section, from 30 to 60$, and
preferably from 40 to 50~ of the cross section of the
strip.
Before proceeding with winding, the starting end
of the flexible strip 9 is fastened at l7, in any known
manner whatsoever, for example by bonding, to the
peripheral wall of the pipeline 2. This end may also be
held in place by the means 16 for pressing the strip or
by the first wound turn of the strip.
All that which has been said above for laying
down a first layer such as 5a on the external surface of
a pipeline 2 is entirely valid for laying down a second
layer 5b on the layer 5a, then for laying down a third
layer 5c on the layer 5b: the melted material of the
strip of the new layer adheres perfectly to the material
of the strip of the previous layer, and the leaktightness
of the new layer is ensured by the pressure of the roller
16, as is the elimination of any inclusion. _
As represented in detail in Figures 2 and 3, the
lower layer 5a covers a length of the pipeline 2 greater
than those which the successive layers 5b, 5c respec
tively cover, so that the prestress exerted on the
material of the pipeline or container decreases progres
sively from a predetermined point when moving away from
the fault 1 on either side of the latter.
In the embodiment of Figure 5, a device in
accordance with a first embodiment of the invention and
indicated generally by the reference number 18 is sus-
pended from a support 19 intended to bear on the ground
~(or on the seabed). The support 19 may itself be sus-
pended from the hook 20 of a lifting machine, not shown,
and receives, via a flexible link 21 connected to an
actuation unit on the ground ( or on the surface for a
sub-sea pipe) all the fluids and information necessary
for actuating the device 18. The support 19 comprises all
the elements, projectors, cameras, sensors, etc. (not
shown), allowing remote control of the device 18 and
monitoring of the winding obtained, in particular in the
- 17 -
case of a sub-sea pipe. In this latter case, the support
1f may also be arranged so as to serve as diving bell
(not shown).
As represented in detail in Figure 6, the device
18 comprises:
- a chassis 22 intended to bear on the pipeline
2 and if necessary on the ground,
- means 30, 31 for fastening the chassis 22 to
the pipeline 2 and centering it with respect to the
latter,
- equipment 26 which can move with respect to the
chassis 22 and which is intended to revolve with respect
to the chassis 22 around the pipeline 2;
- means 27, 28, 29 for causing the moving
equipment 26 to revolve around the pipeline 2;
- the moving equipment 26 comprising a winding
sub-assembly 42 for supplying and winding a flexible
strip 9 around the pipeline 2 under tension when the
moving equipment 26 revolves around the latter.
In the example shown, the chassis 22 is made up
of two bearing calipers 30 securely fastened respectively
to one of two articulated forks 31, and connected by a
crossmember 32 carrying a suspension clevis 33 to the
support 19 of Figure 5, for example. The articulated
forks 31 each comprise two articulated arme 23 which
close around the pipeline 2 under the action of cranks or
clevises 24 actuated by thrust cylinders 25 in order to
fasten the chassis 22 to the pipeline 2 (see Figures 10
and 11).
As represented in detail in Figures 10 and 11,
these arms 23 may open and close in order to allow the
engagement and disengagement of the forks 31 with respect
to the pipeline 2.
In their open position represented in solid
lines, the thrust cylinders 25, only one of which is
represented for the clarity of the drawing, are in the
retracted position and the arms 23 are pivoted outward
about their respective articulation pin 43 so as to allow
- 18 - 2~9~;~'
the fork 31 to be installed on the pipe 2. The displace-
ment of the thrust cylinders 25 forces the arms 23 to
pivot toward their closed position represented in dashed
lines. In this closed position, fastening jaws 44
provided, on the fork 31 and on the arms 23 are in contact
with the pipeline 2. These jaws 44 may be fastened to the
fork 31 and to the arms 23, and the fork 31 is then
centered on the pipeline by balancing the pressures on
the thrust cylinders 25 for maneuvering the arms 23.
These jaws 44 may also be mounted on telescopic supports
represented diagrammatically at 45 in Figure 11 and
directed radially with respect to the pipeline 2: these
supports then allow the fork 31 and the device 18 to be
fitted onto a pipeline whose external diameter is dis-
tinctly less than the internal diameter of the fork 31,
centering being achieved also by balancing the pressures
on said supports 45.
These jaws 44, whose surface in contact with the
pipeline is advantageously roughened in any known manner
whatsoever, for example by knurling or notching, in order
correctly to immobilize the fork 31 and the device 18 on
the pipeline 2,, may be replaced by rollers allowing the
device to run along the pipeline, as will be seen later.
Use may also advantageously be made of chain-type jaws.
The device I8 of Figure 6 also comprises, between
the caliper 30 and the adjacent fork 31, pivoting block-
ing jaws 46 each clamped against the pipeline 2 by a
thrust cylinder 47 and a crank 47a.
The moving equipment 26 comprises two guide rails
27 having a circular arc-shaped external radial edge and
respectively associated with the mutually opposite faces
of the two forks 31 of the device 18. Each of these
external edges is a rack which bears and meshes at the
same time on several rollers 28 belonging to a set of
cogged rollers 28 mounted on the fork 31 and at least
some of which are drive rollers driven by controlled motors
' 29, for example hydraulic motors, fastened to the cor-
responding fork 31. The rollers 28 are distributed
- 19 -
substantially evenly over the actual fork 31 and over the
arms 23 so that the guide rail 27 is permanently in
contact with at least two rollers 28 which drive it in
its rotational movement around the pipeline.
The guide rail 27 is, for this reason, fitted
with any means whatsoever known per se for holding it on
its trajectory in contact with the rollers 28, for
example another guide rail or sections of guide rail
mounted to overhang, and bearing on other rollers (not
shown) fastened to the fork 31.
The outer edge of the guide rail 27 and the
rollers 28 may be smooth, in particular for pipelines of
relatively small diameter: the pressure of the rollers 28
on this edge is then sufficient to drive the guide rail
27 and~the moving equipment 26 rotationally around the
pipeline 2.
The guide rails 27 are connected to each other by
several pairs of longitudinal slideways 34, 35.
A carriage 36 can move in the longitudinal
direction of the pipeline 2 on the two slideways 34 under
the action of a ball screw 37 controlled by a two-way
motor 38. The carriage 36 carries the winding sub
assembly 42 already described above with reference to
Figure 4, only the pulley 7 of which is represented in
the figure for reasons of clarity of the drawing.
The speed of the screw is adjusted as a function
of the coiling angle which it is desired to obtain.
Likewise, a carriage 39 which can move on the two
slideways 35 under the action of a ball screw 40 carries
a presser roll 16, already described with reference to
Figure 4, this roll 16 completing the action of the one
which forms part of the winding sub-assembly 42 carried
by the carriage 36, or capable of replacing it.
Tn the embodiment represented in Figure 7, the
elements identical to those described above with
reference to Figures 4 and 6 carry the same reference
numbers as the latter.
--,
- 20 -
In this embodiment, the device 48 comprises a
chassis 49 made up of a bearing caliper 50 and an articu-
lated fork 51, connected to each other by centering
spacers 52, a crossmember 53 and a suspension clevis 54.
The caliper 50 carries thrust cylinders 55 which actuate,
by means of cranks 56, blocking jaws 57 which push with
force onto the pipeline 2 in order to fasten the device
48 onto the latter. The fork 51 is substantially
identical to the fork 31 of Figure 6, and particularly
comprises two articulated arms 23 which close around the
pipeline 2. The moving equipment 58 comprises a single
guide rail 27 whose circular arc-shaped outer edge
forming a rack bears on a set of cogged rollers 28
distributed substantially evenly over the fork 51 and its
arms 23 and externally tangential to the rack 27.
The two longitudinal slideways 59 are mounted
overhanging the guide rail 27, and support the carriage
36 which can move along the latter under the action of
the screw 37. The carriage 36 carries the winding sub-
assembly 42 only the braked spool 7 of which has been
represented for the clarity of the drawing.
In the embodiment represented in Figure 8, the
device 60 substantially corresponds to two devices such
as 18 arranged one behind the other in the longitudinal
direction of the pipeline 2.
Two sets of moving equipment 26a, 26b are capable
of revolving respectively between the forks 31a and 31b
on the one hand, and 31b and 31c on the other hand. The
rollers 28 which mesh with the rack of the corresponding
guide rail 27 have two-way motors 29. It is therefore
possible to make the two sets of moving equipment revolve
around the pipeline 2 either in the same direction, or
preferably in opposite directions identified respectively
by the arrows 61a and 61b: in this latter case, the
reaction forces applied respectively to the device 60 due
to the rotation of the moving equipment 26a and 26b
substantially balance one another out, so that the device
60 does not tend to revolve around the pipeline 2. The
- 21 -
arrangement of the winding sub-assembly 42b on the
carriage 36b of the moving equipment 26b is, of course,
matched to the direction of rotation of the latter (arrow
61b).
The device 60 is capable of being displaced by
its own means in the longitudinal direction of the
pipeline 2, either in the direction of the arrow 62a, or
in the opposite direction indicated by the arrow 62b.
For this purpose, the calipers 30a, 30b and/or
the forks 31a, 31b, 31c of the device 60 comprise rollers
such as 63 driven by motors, not shown, which serve both
to hold the device 60 in place on the pipeline 2 and to
displace it longitudinally on the latter. These rollers
63 may be mounted on sprung supports or telescopic
supports already described above with reference to
Figures 10 and 11.
Of course, the rollers 63 may not be driven, the
device 60 being displaced along the pipeline 2 by any
means whatsoever external to the device 60.
Finally, the device of the invention may also
serve to reinforce or to reclaim a section of the
pipeline which may comprise bends. These bends are, with
respect to the median plan of the pipeline, defined by
the axis and the horizontal diameter of the latter at the
point of departure of the bend, either bends to the right
or to the left, or bends upward or downward, or
combinations of the previous bends.
Tn order to optimize the winding conditions of
the strip around bends in the pipeline, the winding sub
assembly 52 is mounted on the carriage 36 so as to be
able to move with respect to the latter along five axes:
such a mounting, known per se, is represented diagram-
matically in Figure 9. In this figure, the axis 64 of the
pipeline 2 and the winding sub-assembly diagrammatically
represented by the spool 7 whose rotational axis X-X' is
substantially parallel to the axis 64 are represented.
The axis Y-Y' corresponds to the horizontal diameter of
the spool 7 perpendicular to the axis X-X', and the axis
z~~~~~~
- 22 -
Z-Z' is perpendicular to the two axes X-X' and Y-Y'.
The winding sub-assembly must thus be capable of
moving with respect to the carriage (not shown) along
each of the three axes X-X', Y-Y', Z-Z' and be capable of
revolving around the axis Z-Z' (arrow 65) for bends to
the left and to the right, and about the axis Y-Y' (arrow
66) for bends upward and downward, as well as in the
respective opposite directions.
The winding sub-assembly may thus be mouq~ted with
respect to the carriage, in the same way as a robot wrist
is mounted with respect to the body of this robot, the
various movements being controlled and coordinated by a
computer. Such a sub-assembly can be fitted to any one
whatsoever of the embodiments of the device of the
invention.
Generally, the movements of the elements securely
fastened to the calipers 30, 50 and/or the forks 31, 51
are, for example, hydraulically controlled: this relates
to the motors 29 of the rollers 2B, the thrust cylinders
25 for actuating the articulated arms, the thrust
cylinders 47, 55 for actuating the blocking jaws 46, 57,
the telescopic supports 45 of the jaws 44, etc.
The energy used on the moving equipment 26, 58,
is preferably electrical and is, for example, picked up
by means of insulated wipers (not shown) carried by one
of the rails 27 and wiping on two insulated rails under
tension (not shown) carried by the adjacent face of the
corresponding fork 31: this relates in particular to the
screws 37, 40 actuating the carriages 36, 39, the
-actuation of the hot gas blow torch 14, etc.
There will now be described, with reference to
the figures, the operational mode of the various afore-
mentioned embodiments of the device of the invention.
Insofar as the device 18 of Figure 6 is
concerned, it is supplied to.the pipeline by means of any
kind of .lifting machine whatsoever, for example the
support 19, and it is fastened to the pipeline 2 by means
of the jaws 46 and the jaws 44; the motors 29 actuating
- 23 _ N~~l~~'
the rollers 2B, which drive the guide rails 27 and the
moving equipment 26 rotationally around the pipeline. At
the same time and in a coordinated fashion the carriage
36 is displaced along the slideways 34 over the entire
length of the latter in order to lay down a first layer
of strip such as the strip 5a of Figures 2 and 3,
covering a zone whose length is at most equal to that of
the slideways 34.
The preceding text also applies to the device 48
of Figure 7.
- The device 60 of Figure B is particularly suited
to producing a reinforcement over a considerable length
of a pipeline. It may comprise more than two sets of
moving equipment 26 revolving alternately in one
direction and the other in order to lay down, at the same
time, whilst advancing, a number of layers of strip equal
to the number of sets of moving equipment. The device 60
is normally displaced along the pipe, the carriages 36
being fastened to the longitudinal slideways.
A method and a device are thus being described
which are alone in making it possible to carry out
repairs on high-pressure primary networks for transport-
ing fluids such as, for example, petroleum products or
natural qas.
Of course, the invention is not limited to the
embodiments which have just been described, and numerous
changes and modifications can be made to the latter
without departing from the scope of the invention.
- The calipers 30, 50, the articulated forks 31,
-51, the longitudinal slideways 34, 35, 59, the ball
screws 37, 40, the arms 23, the thrust cylinders 25, 55,
the fastening jaws 44, the telescopic supports 45, the
jaws 46, etc., and in general all the constituent
elements of the devices described may thus be replaced by
equivalent means fulfilling comparable functions. These
elements may equally well be combined in order to fulfil
the various functions described above for fastening and
displacing the device along the pipeline, rotating the
~t
- 24 -
moving equipment with respect to the chassis and to the
pipeline, displacing the carriage with respect to the
chassis.
Likewise, the device 60 of Figure 8 may be
equipped with moving equipment 26a, 26b which does not
comprise slideways 34a, 34b, 35a, 35b: the carriages 36a,
36b may be fastened to the corresponding guide rail 27.
In contrast, each set of moving equipment such as
26 or 58 may comprise several carriages each carrying a
winding sub-assembly, or a single carriage carrying
several winding sub-assemblies, such as 42, so as to wind
several strips at the same time.
There may also be designed, for wavy pipeline
outlines, individual chassis, each carrying a set of
moving equipment, articulated with respect to one another
to allow several layers to be wound whilst advancing,
even for wavy outlines.
The devices described may also be adapted- to
systems forming a diving bell to allow the implementation
of the invention out of the water on sub-sea pipelines.
Under such conditions, the device may be adapted to
automatic, remote-controlled operation. Thus, the spool
7 may comprise a motor in order to supply the strip, and
the winding sub-assembly may comprise guides for supply-
ing the strip between the braking rollers, in front of
the blow torch and as far as the pipeline, as well as a
guillotine in order to be able to cut the strip in the
case of an incident and to recommence the winding process
under'good conditions.
It is possible to mount on the carriage 36,
instead of or beside the winding sub-assembly 42, sub-
assemblies allowing other operations such as the addition
of blocking-off material, the surfacing of this material
after laying down, the application of the primary binding
coating, the removal of the initial protection or ballast
materials before repair, etc.
Generally, the device of the invention may be
supported entirely by the pipeline or container to be
r~~~f~~,~~ _
- 25 -
repaired. It may, in contrast, be suspended from a
carrying machine such as 19 (Figure 5) which may itself
be immobile or, to the contrary, be self-propelled, its
legs being, for example, equipped with caterpillar tracks
or wheels. The device of the invention could equally well
rest on the ground by means of its own support means,
such as adjustable feet, if appropriate fitted with
displacement means such as wheels or caterpillar tracks
to make the device self-propelled.
Finally, all the preceeding text relates to the
helical winding of a strip in successive segments as a
helix. The method and the device of the invention may
equally well use another winding process making it
possible to cover a substantially cylindrical surface
completely: they may thus make use of a process in which
one or more spools are stored on the pipeline to be
covered without revolving around the latter; the
corresponding strips are brought longitudinally as far as
a set of moving equipment which alternately revolves in
one direction then the other, each time by more than a
revolution, in order completely to cover, in one or more
passes, the entire surface of the pipeline: it also being
possible to uae several sets of moving equipment at the
same time in order to lay several layers one above the
other in the same operation.
