PRESSURE ELEMENT FOR A LIQUID TRANSPORT TUBE WITH AN INNER PROTECTIVE LINING AND USAGE METHOD

Description

Technical Field

[0001] The present invention relates to the general field of pipes made by assembling steel pipe elements and comprising an internal plastic lining protecting the steel walls of the pipes from corrosion.

[0002] The present invention relates more specifically to pipes carrying corrosive fluids, in particular subsea pipes carrying pressurized seawater intended to be injected into oil field wells. Previous technique

[0003] Such underwater pipelines are generally constructed by butt welding the ends of steel pipeline sections. The steels constituting the pipelines and the welds between pipeline sections can be subject to corrosion when the pipeline carries a corrosive fluid, particularly water or a fluid containing water, and especially salt water.

[0004] A known solution to this problem involves protecting the internal steel surface of the pipe from corrosion by applying a lining (also called a "liner") made from a flexible thermoplastic material. However, the ends of the pipe sections must not be pre-coated with this protective lining. This is because the lining cannot withstand the high temperatures involved in welding the pipe sections together.

[0005] To ensure continuity of the thermoplastic protective coating at the ends of the two pipe sections to be welded, a common method is to insert a tubular joining sleeve made of corrosion-resistant material into the pipe. This sleeve then overlaps the ends of the two protective coatings inside the pipe, directly at the weld point. This type of solution eliminates the need for corrosion-resistant alloy steel lining and / or welding with corrosion-resistant alloy steel. However, these tubular joining sleeves are complex and expensive to install.

[0006] A solution for directly joining weldable pipe sections with a peripheral weld made of corrosion-resistant steel is also known from document WO 2020 / 053511 (FR3085736). A corrosion-resistant alloy steel compression ring is inserted inside the end section of each pipe section to protect and insulate the end section from the protective coating during welding of the pipe section ends.

[0007] This solution thus makes it possible to ensure protection against corrosion of the internal wall of the pipe with a protective coating of thermoplastic material on the running part of the pipe elements and an anti-corrosion steel coating on the welded ends of the two pipe elements, and this without resorting to a tubular joining sleeve and / or without interposing a steel connecting piece smaller than the pipe element to be welded between the two pipe elements on the other hand.

[0008] In this solution, the compression ring includes a truncated conical end portion to create a progressive variation in the internal diameter of the pipe at the transition between the end portion of the unlined anti-corrosion alloy layer and the end portion of the plastic coating which is thicker than the second end portion of the unlined anti-corrosion alloy layer.

[0009] However, such a compression ring has the disadvantage of being difficult to force into the pipe because its truncated conical end does not offer sufficient contact surface for a thrusting tool (typically a hydraulic piston). A thrusting tool specifically designed for this type of compression ring must therefore be used. Description of the invention

[0010] The invention therefore aims to provide a compression device that can be easily inserted into the pipe by a conventional pushing tool while facilitating the passage of scrapers inside the pipe.

[0011] This purpose is achieved by means of a compression device for a fluid transport pipe equipped with an internal protective lining, comprising an annular ring intended to be press-fitted into the pipe and comprising a downstream insertion end having a frustoconical shape, an upstream thrust end opposite the insertion end, and a substantially cylindrical central portion connecting the upstream and downstream ends and intended to compress one end of the internal protective lining against an internal wall of the pipe, in which, according to the invention, the thrust end comprises: an annular collar projecting radially outwards and forming a bearing surface for a ring pusher tool inside the pipe; an annular cavity formed upstream of the collar; and an annular cavity filler element intended to be inserted inside the cavity of the ring, the filler element being a part independent of the ring and having a frustoconical shape to facilitate the passage of scrapers inside the pipe once the filler element is inserted inside the cavity of the ring.

[0012] The invention is remarkable in particular in that it offers a compression member equipped with both a straight support surface to allow the pushing tool to take hold in order to force the ring inside the pipe, and a truncated conical shape allowing it to facilitate the passage of scrapers inside the pipe.

[0013] Preferably, the ring cavity includes at an upstream end a rim projecting inwards to ensure axial locking of the filling element once it is inserted inside the cavity.

[0014] According to a first embodiment, the filling element is a truncated cone-shaped crown made of polymer material which is able to deform in order to be forced into the cavity of the ring.

[0015] According to a second embodiment, the filling element consists of a material injected into a truncated cone-shaped mold previously positioned around the cavity.

[0016] According to a third embodiment, the filling element is a frustoconical ring made of polymer material and split to allow a reduction in its diameter when forced into the cavity of the ring.

[0017] In this embodiment, the ring may further include a stop bead housed in an annular groove so as to ensure retention of the ring in the cavity of the ring.

[0018] Regardless of the embodiment, the upstream end of the ring is advantageously welded to the inner wall of the pipe.

[0019] Furthermore, the frustoconical shape of the ring's insertion end is advantageously flared downstream and the frustoconical shape of the filling element is flared upstream.

[0020] The invention also relates to a method of mounting the compression member as defined above inside a fluid transport pipe equipped with an internal protective lining, comprising the force insertion of the ring inside the pipe using a pushing tool bearing against the flange of the pushing end, the welding of an upstream end of the ring to an internal wall of the pipe, and the insertion of the filling element inside the cavity of the ring.

[0021] In the case of an application to a compression element according to the first embodiment, the crown forming the filling element is advantageously deformed by heating prior to its insertion inside the cavity of the ring.

[0022] In the case of an application to a compression element according to the second embodiment, the step of inserting the filling element advantageously includes placing the frustoconical mold around the cavity of the ring, injecting a material into the mold to fill it, cooling the injected material, and removing the mold.

[0023] In this case, the material injected into the mold can be an epoxy resin, a polyurethane foam, or a polyethylene foam.

[0024] In the case of an application to a compression member according to the third embodiment, the ring forming the filling element is advantageously deformed by reducing its diameter prior to its insertion inside the cavity of the ring. Brief description of the drawings

[0025] [ Fig. 1 ] There figure 1 is a partial perspective view of a compression device according to a first embodiment of the invention. Fig. 2A ] ; ] Fig. 2B] ; [Fig. 2C ] THE figures 2A Figures 1 and 2C are schematic views of different stages in the assembly of the compression element of the figure 1 . [ Fig. 3A] ; [Fig. 3B ] ; ] Fig. 3C ] THE figures 3A à 3C represent steps in the assembly of a compression device according to a second embodiment of the invention. Fig. 4 ] There figure 4 is a schematic and perspective view of a compression device according to a third embodiment of the invention. Description of the implementation methods

[0026] The invention relates to a compression device intended to be inserted inside a conduit for transporting corrosive fluids which is equipped with an internal protective lining.

[0027] The compression element according to the invention consists of an annular ring as shown in the figure 1 and a filling element that fits into a cavity in the ring.

[0028] There figure 1 represents schematically and in perspective an annular ring 2 of a compression member according to a first embodiment of the invention.

[0029] As depicted on the figures 2A à 2C , this ring 2 is intended to be inserted by force inside a conduit 4 for the transport of corrosive fluids equipped with an internal protective lining 6, made for example of a thermoplastic material.

[0030] The ring 2 has an axis of revolution XX which is centered on the axis of the conduit 4 when it is inserted inside it.

[0031] The ring 2 comprises a downstream insertion end 8 having a frustoconical shape, an upstream thrust end 10 opposite the insertion end, and a substantially cylindrical central part 12 connecting the downstream ends 8 and upstream ends 10.

[0032] The central part 12 of the ring is intended to compress the end of the inner protective lining 6 against the inner wall of the pipe 4.

[0033] According to the invention, the thrust end 10 of the ring 2 includes, in particular, an annular flange 14 that projects radially outwards. This flange 14 has a rear flat face 14a that extends in a radial direction (relative to the axis of revolution XX of the ring) and thus forms a bearing surface for a tool to push the ring inside the pipe.

[0034] The thrust end 10 of the ring 2 also includes an annular cavity 16 which is formed upstream of the flange 14. As shown in the figure 2A , this cavity 16 is radially projecting relative to the central part 12 of the ring and rests directly against the inner wall of the pipe.

[0035] The thrust end 10 of the ring further includes an annular filling element 18 which is intended to be inserted inside the cavity 16.

[0036] This filler element 18 is an independent part of the ring 2 (in particular, it is inserted into the pipe after the ring has been inserted). It has a portion 18a with a frustoconical shape to facilitate the passage of scrapers inside the pipe once it has been inserted into the cavity of the ring.

[0037] Furthermore, in order to ensure axial locking of the filling element 18 once it is inserted inside the cavity 16 of the ring, the latter includes at an upstream end a rim 20 projecting inwards.

[0038] Several methods of implementing the filling element are possible.

[0039] THE figures 2A à 2C show a first of these embodiments. In this first embodiment, the filling element is a truncated cone-shaped crown 18 made of polymer material and capable of deforming to fit tightly into the cavity 16 of the ring.

[0040] As depicted on the figure 2A , the ring 2 is first inserted by force into the pipe 4 by means of a pushing tool (not shown), typically a hydraulic piston, which comes to bear against the bearing surface 14a of the collar 14 of the ring.

[0041] When the ring 2 is correctly positioned, the polymer material crown 18 is in turn inserted inside the pipe 4 by means of another tool (not shown).

[0042] When the crown 18 reaches the rim 20 of the ring cavity ( figure 2B ), it deforms locally in order to be able to overcome this obstacle and pass beyond.

[0043] Once it has passed the rim 20, the crown returns to its original shape and fits inside the cavity 16 ( figure 2C ). Given its truncated cone-shaped part 18a, the compression member thus has a truncated cone shape at its two longitudinal ends, thus facilitating the passage of scrapers inside the pipe (in both directions of advance).

[0044] It should be noted that to facilitate its local deformation and insertion into the ring cavity, the crown 18 can advantageously be deformed by heating prior to its insertion into the ring cavity. Once the crown is installed in the cavity and cooled, it regains its initial rigidity.

[0045] THE figures 3A à 3C represent a second possible embodiment for the filler element.

[0046] In this embodiment, the filling element is composed of a material 18' which is injected into a truncated cone-shaped mold 22 previously positioned around the cavity 16.

[0047] More specifically, once the ring 2 is correctly positioned inside the pipe 4, a mold 22 having a truncated cone shape is inserted inside the pipe to position itself around the cavity to close it ( figure 3A ).

[0048] The mold 22 includes at least one injection port 22a, and at least one air vent port 22b.

[0049] The empty volume of the closed cavity 16 is then filled by injecting (via the injection port 22a) epoxy resin materials, polyurethane foam or polyethylene foam ( figure 3B During filling, the air is gradually replaced by the injected materials and escapes from the cavity through the air vent 22b.

[0050] Once the cavity volume is completely filled with injected materials, the mold is removed from the pipe. The cavity 16 is then filled with a filler element 18' and the compression member thus has a frustoconical shape at its two longitudinal ends ( figure 3C ).

[0051] There figure 4 represents a third possible embodiment for the filler element.

[0052] In this embodiment, the filling element is a 22" frustoconical ring made of polymer material and split to allow a reduction in its diameter when forced into the cavity of the ring.

[0053] As depicted on the figure 4 , the 22" ring has a 24" slot which allows its diameter to be slightly reduced in order to facilitate its forced insertion inside the cavity of the ring.

[0054] Once ring 2 is correctly positioned inside pipe 4, ring 22" is deformed by reducing its diameter to facilitate its insertion into the ring's cavity. When the ring is correctly positioned inside the cavity, the deformation ceases and it returns to its original diameter.

[0055] Advantageously, the 22" ring further includes a 26" stop ring (circlip type) which is housed in an annular groove so as to ensure retention of the ring in the cavity of the ring.

[0056] It should be noted that, regardless of the method of embodiment of the compression element, the upstream end 10 of the ring 2 is preferably welded to the inner wall of the pipe.

[0057] It should also be noted that the truncated conical shape of the insertion end 8 of the ring 2 is flared downstream, while the truncated conical shape of the filling element 18, 18', 18" is flared upstream.

Claims

1. A compression member for a fluid transport pipeline (4) provided with an inner protective liner (6), comprising an annular ring (2) intended to be forcibly inserted inside the pipeline and which comprises a downstream insertion end (8) with a frustoconical shape, an upstream pushing end (10) opposite to the insertion end, and a substantially cylindrical central portion (12) connecting the upstream and downstream ends together and intended to compress one end of the inner protective liner against an inner wall of the pipeline, characterized in that the pushing end (10) comprises: - an annular flange (14) protruding radially outwards and forming a bearing surface (14a) for a tool pushing the ring inside the pipeline; - an annular cavity (16) formed upstream of the flange; and - an annular element (18; 18'; 18") for filling the cavity, intended to be inserted inside the cavity of the ring, the filling element being an independent part of the ring which has a frustoconical shape so as to facilitate the passage of scrapers inside the pipeline once the filling element is inserted inside the cavity of the ring.

2. The member according to claim 1, wherein the cavity (16) of the ring (2) comprises, at an upstream end, a rim (20) protruding inwards to ensure axial blocking of the filling element once it is inserted inside the cavity.

3. The member according to any of claims 1 and 2, wherein the filling element is a frustoconical crown (18) made of polymer material which is able to deform in order to be forcibly inserted into the cavity (16) of the ring.

4. The member according to any of claims 1 and 2, wherein the filling element is composed of a material (18') injected into a frustoconical mold (22) previously positioned around the cavity (16) of the ring.

5. The member according to any of claims 1 and 2, wherein the filling element is a frustoconical annulus (18") made of polymer material and split so as to allow a reduction in its diameter during its forcible insertion into the cavity (16) of the ring.

6. The member according to claim 5, wherein the annulus (18") further comprises a snap ring (26) housed in an annular groove so as to ensure retention of the annulus in the cavity of the ring (2).

7. The member according to any one of claims 1 to 6, wherein the upstream end of the ring is welded to the inner wall of the pipeline.

8. The member according to any one of claims 1 to 7, wherein the frustoconical shape of the insertion end of the ring is flared downstream and the frustoconical shape of the filling element is flared upstream.

9. A method for mounting the compression member according to any one of claims 1 to 8 inside a fluid transport pipeline (4) provided with an inner protective liner (6), comprising the forcible insertion of the ring (2) inside the pipeline using a pushing tool bearing against the flange (14) of the pushing end (10), the welding of an upstream end of the ring on an inner wall of the pipeline, and the insertion of the filling element (18; 18'; 18") inside the cavity (16) of the ring.

10. The method according to claim 9 when dependent on claim 3, wherein the crown (18) forming the filling element is deformed by heating prior to its insertion inside the cavity of the ring.

11. The method according to claim 9 when dependent on claim 4, wherein the step of inserting the filling element comprises the placement of the frustoconical mold (22) around the cavity of the ring, the injection of a material (18') into the mold to fill it, the cooling of the injected material, and the removal of the mold.

12. The method according to claim 11, wherein the material injected into the mold is an epoxy resin, a polyurethane foam or a polyethylene foam.

13. The method according to claim 9 when dependent on claim 5, wherein the annulus (18") forming the filling element is deformed by reduction of its diameter prior to its insertion inside the cavity of the ring.