FR2763380A1 - ELONGATE PROFILE ELEMENT CAPABLE OF CHANGING CURVATURE AND METHOD OF MANUFACTURING THE SAME - Google Patents

Abstract

The invention concerns an abrasionproof elongate streamlined element in composite material capable of changing its bend. The streamlined element comprises an elongate hollow body (1) and means (9) made of a composite material stabilised inside the elongate body. The elongate hollow body comprises one or several mechanical fixing means (24) which serve to maintain the composite, material means inside the elongate body, while allowing the means to move axially relative to the elongate element.

Description

 The present invention relates to an elongated profile of great length in composite and its manufacturing process, the profiled element having high mechanical characteristics in the longitudinal axis and being in particular capable of withstanding local stresses and / or abrasion.

 Such profiled elements find their application in particular in the manufacture of flexible pipes, or flexible pipe elements, by helical winding, these pipes having in particular characteristics of high resistance and qualities of lightness.

 The profiled elements used to manufacture flexible pipes include in the majority of cases, a support inside of which is placed a core.

During manufacture and during their use, for example when such elements are used to form reinforcements formed by several plies, it is necessary that the profiled elements resist:
to the local "overbending" which may result from the support on which the element is
willing,
with alternating bending forces, the core having to remain inside the
support while retaining a certain freedom with respect to the support, and
abrasion and friction, the pipe can be formed of several
layers of elements arranged one above the other.

 The prior art describes various embodiments which make it possible to maintain the core inside the support whatever the stresses seen by the pipe, and to resist the abrasion phenomenon.

 Certain methods consist in placing an anti-abrasion material on at least one surface of the profile to be protected, or in completely covering the profile after its manufacture. Such operations require an additional step which significantly increases the cost of manufacturing the profile. In addition, the abrasion-resistant material must have adhesion characteristics with respect to the profile, which restricts the choice of materials that can be used.

 Another way to do this is to use an adhesive to adhere the abrasion-resistant coating to the profile. In this case, the nature of the adhesive must be compatible both with the material constituting the profile and with the abrasion-resistant coating. This double constraint restricts the range of materials likely to be used and increases the cost of the elements.

 In addition, the use of an adhesive does not allow the desired degree of axial freedom of the core to be maintained relative to the support.

 Patent FR 2,494,410 describes different embodiments of a profiled element.

 A first way is to use a mold made of abrasion-resistant material and to fill it with a reinforced plastic material adhering to its internal wall, the nature of the material being chosen to ensure the retention of the core in the mold. Such a choice restricts the materials used for the mold, since it requires in particular the existence of compatibility between the materials used for the mold. In addition, the degree of axial freedom between the core and the support is nonexistent and bending forces induce cracks in the material forming the core.

 One way of ensuring a certain degree of axial freedom between the core and the support therefore consists in depositing petroleum jelly inside the support. In this way, a degree of axial freedom is maintained between the core and the support. However, when the element is subjected to bending, for example, the core tends to "wiggle", to come out of the support.

The purpose of the present invention is to overcome the drawbacks of the prior art and in particular to offer a profiled element and its manufacturing process having the following characteristics:
resistance to changes in curvature of the profiled element due to
axial degree of freedom retained between the core and the support,
abrasion resistance.

 In the following description of the present invention, the term "composite material" means a material which may comprise fibers, such as glass fibers, carbon fibers, aramid fibers, coated in a matrix, such as a thermosetting or crosslinkable matrix, or any other material which requires treatment to bring it into its final state.

 The expressions “elongated body” and “hollow elongated body” denote throughout the rest of the description the same element, for example a body, preferably resistant to abrasion due to the very nature of the material of which it is made and / or of the made of the geometric characteristics of this mold, for example its thickness, which make it possible to maintain sufficient resistance to abrasion. The term "core" refers to the stabilized composite material.

 Thus, the invention relates to an elongated profiled element of composite material, the element being capable of being bent, and capable, preferably, of resisting abrasion, the profiled element comprising a hollow elongated body, a core made of composite material stabilized inside the elongated body.

 It is characterized in that the hollow elongated body comprises one or more mechanical fixing means which make it possible to hold the core of composite material inside the elongated body, while leaving the possibility of the core to move axially at the inside the elongated element.

 This avoids the loosening of the core of the hollow elongated body during possible changes in curvature of the profiled element, and a certain degree of axial freedom is preserved mainly in the longitudinal or axial direction of the element.

 The elongated body may comprise at least one groove, and the mechanical fixing means may be located on at least one of the walls of this groove, for example the wall which forms the bottom of the groove and / or at least one of the side walls of the throat.

 These mechanical fixing means may include a part "i" on the side walls of said elongated body which is inserted, for example, into the core of composite material, the core having a width "n", the value of "i" is between 0.05n and 0.25n, for example, and preferably between 0.08n and 0.130n.

 The mechanical fixing means are, for example, formed by one or more elongated elements which extend over at least part of the length of one or more of the walls of the groove.

 According to another embodiment, the fixing means are formed by one or more elongated elements which extend over at least part of at least one of the walls of the groove, for example, grooves having a depth "r" . The ratio of the value of the depth of the groove to the thickness "e" of the groove is for example between 0.1 and 04.

 The mechanical fixing means can also be formed from one or more parts of the hollow elongated body, for example by a forming operation.

 The fixing means can also be in the form of a "T" having a width at the bottom 11 and a width at the top 12, the width 12 being, for example, less than 0.5 n and the value of li being such that ( 12) / 3> l1> 0.1 n, where "n" is the width of the core of composite material.

 The mechanical fixing means can also be point elements such as hollows and / or studs distributed over at least part of the length of at least one of the walls.

 For hollows having a depth "p" and a wall of the hollow elongated body having a thickness "e", the ratio p / e is for example between 0.1 and 0.5.

 The present invention also relates to a manufacturing method making it possible to obtain a profiled element capable of changing curvature and capable of withstanding abrasion.

The method is characterized in that the following steps are carried out for example:
a hollow elongated body is used which is preferably adapted to withstand
abrasion, the elongated body comprising at least one fixing means
mechanical and / or means for forming a fixing means
mechanical, the mechanical fixing means allowing movement
axial between the core and the elongated body, and
said hollow elongated body is filled with a composite material,
According to an embodiment of the method, for example the elongated hollow body lined with the composite material is subjected to a treatment capable of passing it into its final state, this treatment operation possibly being carried out before or after the manufacture of the element.

 The mechanical fixing means can be formed before or after the stage of final shaping of the composite material.

 The present invention is particularly applicable to the manufacture of a flexible pipe comprising at least one elongated profiled element according to the invention, and in particular to the manufacture of a flexible pipe used in the petroleum field.

Compared to the known prior art, the profiled element having the characteristics set out above, as well as its manufacturing process, have numerous advantages and solve several problems, and in particular the following:
the presence of mechanical fixing means or mechanical holding to
instead of the chemical means usually used, for example
glues, keeps the core in place while leaving it a certain
degree of axial freedom, that is to say allowing it to move or
axial sliding relative to the elongated body forming the support,
in this way it is possible to choose the materials for the supports
in a much wider range than the usual range
in the prior art,
it is thus possible to use materials whose cost is lower than that of
materials usually used and / or the implementation of which is more
simple.

Other characteristics and advantages of the method and the device according to the invention will appear better on reading the following description of embodiments described by way of nonlimiting examples, referring to the appended drawings, where:
Figure 1 schematically illustrates a process for manufacturing a
profiled element according to the invention,
Figure 2 schematically shows in section the characteristics of
mechanical fixing means distributed over part of an elongated body
hollow coming to be inserted in the core filling the latter,
Figure 3 shows an exemplary embodiment where the fixing means
mechanical, like grooves, extend over practically the entire length
of the two walls of the groove and are inserted into the core,
Figure 4 shows schematically an example of mechanical fastening means which
have in the form of hollow grooves extending over the walls of the
throat,
Figures 5 and 6 show a particular example of a mold comprising
mechanical fixing or holding means formed from a
part of the wall of the hollow elongated body,
FIG. 7 shows an alternative embodiment for which the means of
mechanical fixing are achieved by a T-shaped rail which is inserted
in the nucleus,
Figure 8 shows schematically an embodiment for which the means of
mechanical fixing are in the form of a hollow rail in the wall of the mold,
and
Figure 9 shows a flexible pipe according to the prior art provided
a resistance armature comprising hooking means
mechanical.

 In order to better understand the present invention, the example given below by way of illustration and in no way limitative calls upon a way of manufacturing a profiled element described in detail in the applicant's patent FR 2,494,401, of which only the steps essential and necessary for understanding and implementing the method according to the invention described below are recalled in connection with FIG. 1.

 A hollow elongate body 1 is unwound, for example, from a coil 2 to be wound on a drum or mandrel 3. It passes, for example, between guide rollers 4 and tension rollers 5. The shaft of the mandrel 3 is connected to drive means such as those described in the aforementioned patent or any other means usually used to set the shaft in motion.

 The profiled element produced on the mandrel 3 firstly has a first radius of curvature Rg. This element is then stored, for example on a coil of radius R1 before being wound, for example around a core of a flexible pipe of radius, for example R3. The profiled element passes from radius R2 to radius R3 by an infinite radius.

 The profiled element comprises for example a hollow elongated body 1, being, for example in the form of a longitudinal groove 6, comprising one or more means for fixing or mechanically fastening the composite material in the groove, the means for mechanical fixing being described in more detail in FIGS. 2 to 7 under the references 24, 25, 26, 27, 28, 29, 30, 31, 32.

 This longitudinal groove preferably has a "U" shape, consisting of three walls, one wall of which forms the bottom and two side walls, the angles between each of the side walls and the wall forming the bottom of the groove being between 80 and 100 and preferably around 90 ".

 The groove 6 is, for example, filled as it is wound on the drum, with high resistance filaments 8, or rovings, previously impregnated with a stabilizable matrix, the whole filaments and matrix forming the composite material. or core 9 (Figure 2) of the profile or profiled element.

 The elongated body thus lined with the unstabilized composite material then passes through a treatment device 10 suitable for stabilizing the composite material.

 The means 24, 25, 26, 27, 28, 29, 30, 31 for mechanical retention or fixing may also consist of a part of the mold, for example a part 31, 32 of the wall of the mold, as FIGS. 6 and 7 show this by way of nonlimiting illustration.

 Thus, the process for manufacturing the profiled element may include an additional shaping step, known to those skilled in the art for producing the mechanical fastening means 32. This step is generally carried out after the stabilization of the composite material but could also, without departing from the scope of the invention, be carried out before, during, or even after the manufacturing steps of the profiled element. They can also be preformed.

 The elongated hollow body, when it serves as a support mold, can preferably be adapted to resist abrasion, in particular that resulting from the friction of the different layers between them. Thus, it may be formed for example of a material whose nature has an abrasion resistance itself, or even have geometric characteristics which give it sufficient strength to overcome the abrasion phenomenon. A mold is used, for example, the walls of which may be in contact with other walls have a thickness chosen, preferably, according to the nature of the material to resist these abrasion phenomena.

 In this case, the elongated body is, for example, made of a material chosen from the list of the following materials: polyamide 11, high density polyethylene, polypropylene with or without carbon black, polytetrafluoroethylene or any other material abrasion resistant. The nature of the material chosen is, in all cases, compatible with the stabilization treatment adopted.

One can also use the other plasticized materials or not, loaded or not, given in the following list:
PVDF: polyvinylidene fluoride
PSU: polysulfone
PES: polyethersulfone
PPS: phenylene polysulfide
PEI: polyetherimide
PEEK: polyetheretherketone
PAl: polyamide imide
PFA: polyfluoro-alkoxy
The shape of the fixing means described in relation to the figures given below, their number and their distribution relative to the hollow elongated body are chosen depending in particular on the materials used, the material of the support mold and / or the material forming the core.

 The choice of parameters, such as the shape, number and distribution of the fastening means, may also depend on the forces applied to the profiled element during its use and / or during its manufacture. The element can, in fact, be used alone or even integrated in a flexible pipe as described for example in FIG. 9, obtained by winding one or more layers of profiled elements comprising at least one fixing means for mechanical type. Indeed, the stresses to which the flexible tube is subjected, varying in particular according to its use can generate forces in directions of low resistance, such as the transverse directions for unidirectional composite materials which influence the choice of the fixing means.

 Different examples of fastening means that meet the criteria set out above are described in Figures 2 to 8.

 Figure 2 is given to show, by way of indication, the preferred geometric and dimensional characteristics to be verified by the mechanical fastening means, in particular their dimension relative to the thickness of the wall of the hollow elongated body. The mechanical fixing means are, for example, protuberances 24 extending over a certain length relative to one of the walls of the hollow elongated body which are inserted into the composite material or core 9.

 In this case, it is desirable to limit the part of the means 24 which is inserted into the core in order to keep a section for maximum compression.

 In fact, the pressure applied to the profiled element is inversely proportional to the application surface.

 In the case of a hollow elongated body devoid of mechanical fixing means, the surface or width of application corresponds substantially to the internal width of the groove, that is to say to the distance l separating the interior of the two side walls 21 and 22 of the groove.

 In FIG. 2, the fastening means 24 have a width "i" which fits into the composite material 9 and the width of the groove is "1", which corresponds to a width of application of the pressure that is substantially equal. to l-2i. It is important to minimize the width "i" of the stud penetrating the core while retaining a value sufficient to ensure the maintenance of the core in the mold. This choice is particularly important for molds having a low modulus in compression and the cores of high modulus.

 The width "i" of the fixing means inserted into the composite material is preferably between 0.05n and 0.25n, "n" being the total width of the core corresponding substantially to the internal width of the groove, and preferably between 0.08 and 1.30n.

 When shear stresses exist, the minimum radii of curvature of the fastening means 24 will preferably be greater than 0.2 mm, so as to minimize the initiation of possible cracks in the planes parallel to the fibers.

 The fixing means are preferably distributed symmetrically to balance the core of composite material inside the hollow elongated body and distribute it as uniformly as possible.

 The material of the fastening means may be identical in nature to that of the hollow elongated body, or of a different nature compatible with the material of the elongated element.

 FIG. 3 shows a preferred embodiment of an element according to the invention where the fixing means are formed for example by protuberances, 28, 29, preferably located on each of the side walls 21, 22 of the groove 6 and extending at least in part along its length, like rails.

 These rails are preferably distributed symmetrically along the side walls of the groove 6, that is to say that the rail corresponding to the projection 28 located on the side wall 21 of the groove 6 is opposite. -vis the rail referenced 28 located on the side wall 22 located opposite.

 The rail can extend continuously over the entire length of the groove.

 The effective width of these protuberances 28, 29 is advantageously between 0.05n and 0.25n, with "n" total width of the core, and preferably between 0.08 and 0.130n.

 Such an arrangement advantageously allows the axial displacement or sliding of the core in the groove, the axis with respect to which reference is made being the longitudinal axis of the groove corresponding to that of the elongated element.

 According to another alternative embodiment, it is also possible to distribute several portions of rails or protuberance of similar type to those referenced in FIG. 3 by 28 or 29 over the same height or alternately with respect to each other over several Heights. The lengths of the different rail portions, and the intervals separating these rail portions can take different values chosen of course to ensure the maintenance of the core in the groove. In all cases, the dimensions and arrangement of these various elements are adapted to maintain the axial movement of the core in the groove of the elongated body.

 The shape and size of these protuberances depend for example on their position in the groove 6, in particular on the wall or walls on which they are located.

 In FIG. 4, the mechanical fixing means consist of two recesses such as trenches or grooves 25 and 26, which preferably extend over the entire length of the side walls 21, 22 of the groove 6.

 The composite material forming the core penetrates at least partially into these trenches, to be held in the groove. The shape, the number and the dimension of these grooves are chosen for example with respect to their position in the groove 6, in particular with respect to the wall or walls on which they are located. They are also chosen, for example, according to the number of grooves distributed in the groove.

 The depth of the grooves "r" is fixed relative to the thickness "e" of the wall of the groove, the value of the ratio r / e preferably being between 0.1 and 0.4, to ensure the maintenance of the core in the mold while avoiding weakening the latter.

 Figures 5 and 6 show an example of an elongated body comprising mechanical fastening means which are formed from a portion 31 of the side walls of the elongated body. The fixing means can be shaped during or after the stabilization treatment of the composite material, or the treatment which allows the material constituting the core to pass into its final state.

 Optionally, they can be preformed before filling the groove with the composite material and the fibers forming the core, their final shaping being carried out after the filling step.

 For this, the hollow elongate body comprises, for example in each of the upper parts of the walls 21, 22, a portion 31, swollen or not, which serves as a base for creating mechanical fixing means 32 (FIG. 6).

 FIG. 6 shows the mold and its mechanical fixing means 32 after the shaping step.

 This embodiment advantageously makes it possible to keep the axial displacement of the core with respect to the hollow elongated body.

 FIG. 7 shows another alternative embodiment of a profiled element according to the invention in which the mechanical fixing means is in the form of a protrusion 30 formed at the bottom, or wall of the groove, which extends over a part of the length of the profiled element, such as a rail.

 The rail 30 has for example a shape of "T" having a leg of height "t", a width at the bottom 11 and a width at the top 12.

 The values of the widths l1 12 are chosen for example as a function of the width of the core "n", and preferably in the following manner: l2 <0.5 net (l2) / 3> lî> 0.1n.

 FIG. 8 represents an exemplary embodiment of the profiled element according to the invention where the groove is provided with a single groove 27 situated in its lower wall 23. The groove 27 extends for example over the entire length of the elongated body hollow and has a depth "h". In order to maintain the core in the groove, the ratio h / e, where "e" is the thickness of the wall, is preferably between 0.2 and 0.5. This range of values makes it possible to maintain the core in the groove while preventing the projection thus created in the wall of the groove from weakening the latter.

 It is understood that, without departing from the scope of the invention, the various embodiments of the fixing means described in the preceding figures can be combined with one another and distributed with respect to the profiled element in one of the ways described above. above. They can advantageously be used for the manufacture of a pipe such as that described in FIG. 5.

 The examples given above by way of illustration and in no way limitative in relation to the preceding figures represent hollow elongated bodies having side walls and a bottom wall substantially perpendicular to each other.

 The present invention also applies to hollow elements whose walls make angles of any value.

 It is understood that the thicknesses of the walls forming the hollow profiled element may be different.

 The profiled element as described above comprising a support mold provided with mechanical fixing means is advantageously used to manufacture watertight flexible pipes such as that described by way of illustration and in no way limitative in FIG. 5, the tensile strength reinforcement being produced according to the prior art for example.

 Such pipes can be subjected to significant tensile forces.

This pipe is composed, from the inside to the outside, by:
a flexible internal sheath or tubular core 51, for example of a material
plastic such as a thermoplastic or an elastomer,
a flexible metal frame 52, surrounding the tubular core 51 and resistant
to the forces generated by the pressures prevailing inside and outside
flexible pipe, which may for example consist of
helical winding, low pitch, of a self-stapling profile having a
section in the form of S, Z or T; so the pressure doesn't work
directly on the tubular core 51,
a flexible and waterproof sheath 53, made of a plastic material such as a
elastomer and covering the frame 52 thus protecting it from
external aggressions,
and a tensile strength armature 54. The armature 54 of resistance to
traction is made up of two layers 55 and 56 wound helically
and in reverse with a large winding pitch.

Claims (14)

 1) elongated profiled element made of composite material, said element being capable of changing curvature and, preferably, capable of resisting abrasion, the profiled element comprising a hollow elongated body, a core of composite material stabilized inside of the elongated body, characterized in that the hollow elongated body comprises one or more mechanical fixing means (24, 25, 26, 27, 28, 29, 30, 31, 32) which allow the core of composite material to be held at the inside the elongated body, while leaving the possibility for the core to move axially relative to the elongated element.  2) profiled element according to claim 1, characterized in that said hollow elongated body comprises at least one groove (6), and in that said mechanical fixing means are located on at least one of the walls of said groove (6), such as the wall constituting the bottom of the groove and / or one of the side walls of the groove.  3) profiled element according to claim 2, characterized in that the fixing means (24) comprises a part "i" on the side walls of said elongated body coming to be inserted in the composite material of width "n" and in that "i" is between 0.05 n and 0.25 n and preferably between 0.08 n and 0.130 n.  4) profiled element according to claim 3, characterized in that said mechanical fixing means consist of one or more elongated elements (28,29) extending over at least part of the length of one or more throat walls.  5) profiled element according to claim 2, characterized in that said mechanical fastening means consist of one or more elongated elements (25, 26) extending over at least part of the length of one of the walls of the groove, such as grooves, having a depth "r" and in that the ratio r / e where "e" is the thickness of the wall of the groove on which the groove is located is preferably between 0.1 and 0.4.  6) profiled element according to one of claims 1 and 2, characterized in that the mechanical fixing means are formed from at least a portion of the hollow elongated body.  7) profiled element according to claim 4, characterized in that said fixing means (30) have a "T" shape having a foot width lî and a head width 12 and in that the width 12 is less than 0 , 5n and in that (12) / 3> lî> 0.1 n, where "n" is the width of the core of composite material.  8) profiled element according to claim 1, characterized in that said mechanical fixing means (24) are point elements such as hollows and / or studs distributed over at least part of the length of at least one of the walls of the hollow body (21, 22, 23).  9) profiled element according to claim 8, characterized in that a hollow having a depth "p" and the wall of the hollow elongated body having a thickness "e", the ratio p / e is between 0.1 and 0.5 .  10) Manufacturing method for obtaining a profiled element capable of changing curvature and capable of withstanding abrasion, characterized in that it comprises the following steps:  using an elongated hollow body adapted to resist abrasion, the body  elongated comprising at least one mechanical fixing means and / or one  means for forming a mechanical fixing means, the means for  mechanical fixing allowing axial movement between the  nucleus and elongated body, and  said hollow elongated body is filled with a stabilizable composite material.  11) Method according to claim 10, characterized in that said hollow elongated body lined with the composite material is subjected to a treatment capable of passing it into its final state, said treatment operation being carried out during or after the manufacture of said body .  12) Method according to one of claims 10 and 11, characterized in that said mechanical fixing means is formed before or after the step of final shaping of the composite material.  13) Elongated flexible body, such as a flexible pipe, comprising at least one elongated profiled element according to one of claims 1 to 8.  14) Application of the method according to one of claims 10 to 12 and of the profiled element according to one of claims 1 to 9 to the manufacture of a flexible pipe used in the petroleum field.