Method for repair by lining and repair kit therefor

Abstract

A method for repairing or reinforcing, by lining a hollow or solid body (3) having a defective area (30), comprising: - delimitation (40) on the outer surface of the body (3) of a portion to be lined (31) including the defective area (30), said body (3) being of thermoplastic material; - making (41) at least one winding of an electro-welding wire (1) around said body (3) on the portion to be lined (31), the electro-welding wire (1) being formed of at least one electrical wire (10) coated in a sheath (11) of thermoplastic material similar to that of said body (3);- positioning (42) of a pre-formed sleeve (2) around the portion to be sleeved (31), said pre-formed sleeve (2) having a cross-section similar in shape to that of the body (3) and having a length (L) equal to that of the portion to be sleeved (31), said pre-formed sleeve (2) having an opening (20) extending over its entire length, and being made of thermoplastic material similar to that of said body (3), the pre-formed sleeve (2) further comprising an injection vent (5a) and an outlet vent (5b); - carrying out (43) the electro-welding of the sleeve (2) to the body (3) by applying an electric current to the winding for a predefined duration, simultaneously with a progressive tightening of the sleeve (2) on the body (3).

Description

Domaine technique

[0001] The present invention relates to a method of repairing by lining a hollow or solid body made of plastic material, such as for example a conduit or a pipe made of high density polyethylene (HDPE). Technique antérieure

[0002] In civil engineering structures, such as bridges, constructed from external prestressed concrete, some prestressing cables or strands are placed in conduits to protect them from external aggressions likely to cause their corrosion. The most common solution is to insert these cables into high-density polyethylene (HDPE) conduits, particularly in the parts where the cable is free, i.e. not passing through the concrete, and a cement grout can be injected into the conduit.

[0003] When these pipes have mechanical defects or weaknesses, such as cracks, different repair solutions are proposed, such as the use of heat-shrinkable sleeves around the portion with a defect, or the use of "vulcanizing" repair tape coupled with stainless steel sleeves. These repair solutions, although economical and quick to execute, are not durable because they are sensitive to vibrations and the adhesion of these sleeves to certain surfaces, particularly on an HDPE pipe, remains difficult.

[0004] Another solution is to use stainless steel mechanical sleeves or "multi / clamps". In practice, the use of this type of sleeve in bulky or difficult-to-access environments remains very difficult to implement. Indeed, this solution does not guarantee long-term sealing due to the vibration context associated with the high coefficient of expansion. Exposé de l'invention

[0005] The present invention therefore aims to propose a long-lasting and waterproof repair solution, suitable for the repair of hollow or solid bodies, made of weldable thermoplastic material, for example HDPE material, and in particular present in civil engineering structures such as bridges made of external prestressed concrete.

[0006] The invention thus relates to a method of repairing or reinforcing, by lining a hollow or solid body having a defective area, comprising: delimitation on the outer surface of the body of a portion to be lined including the defective area, said body being a weldable thermoplastic material; making at least one winding of an electro-welding wire around said body on the portion to be lined, the electro-welding wire being formed of at least one electric wire coated in a sheath made of thermoplastic material similar to that of said body; positioning a preformed liner around the portion to be lined, said preformed liner having a section of similar shape to that of the body and being of equal length to that of the portion to be lined, said preformed liner having an opening extending over its entire length, and being made of thermoplastic material similar to that of said body; making an electro-welding of the liner to the body by applying an electric current to the winding for a predefined duration, simultaneously with a progressive tightening of the liner on the body.

[0007] According to the invention, the preformed jacket further comprises at least two vents, namely an injection vent and an outlet vent.

[0008] In other words, the method consists of placing at least one winding of electro-welding wire around the body between the preformed jacket and the section to be lined. The invention is therefore a repair by jacketing with transverse electro-welding, which can be implemented for repairs that must be carried out in a confined or difficult-to-access space. The method of the invention allows for a durable, watertight seal adapted to the vibration constraints of bridges, thanks to the securing, via a winding of electro-welding wire, of a preformed jacket around the defective section. The single longitudinal opening of the jacket allows in particular a progressive tightening of the jacket around the defective section during electro-welding, so as to properly amalgamate the sheath of the electro-welding wire to the body and the jacket.

[0009] In practice, each vent protrudes from the outer surface of the jacket and can be configured or sized to allow, for example, the introduction of a chemical injection product under optimal pressure conditions. Such an injection product may be petroleum wax-based and intended in particular to ensure the protection of prestressing cables in the decks of civil engineering structures, for example to limit corrosion. Each vent can also be configured to allow inspection of the structure once the jacket repair is complete, for example by injecting a pressurized liquid to test the leaktightness of the repair. These vents can also facilitate subsequent regular testing of the repaired body during the life of the structure.

[0010] Furthermore, depending on the applications, the preformed liner may include more than two vents. For example, the number of vents can be adapted according to the lined length, so as to avoid the appearance of uninjected pockets or deformation of the liner under the effect of the injection pressure. Thus, it is possible to provide several injection points by distributing several vents along the liner in order to reduce the lengths to be injected.

[0011] The present invention is particularly suitable for the repair of hollow or solid bodies located in a constrained or bulky environment, in particular in situations where the implementation of standard plastic welding methods is impossible or difficult to achieve.

[0012] The opening closure can be achieved by longitudinal electro-welding via a separate electro-welding rod or via a part of the winding by extrusion welding.

[0013] In practice, the winding can be formed from a continuous winding or from several separate and independent windings, depending on the length and diameter of the portion to be lined as well as the thermoplastic material.

[0014] According to one variant, the winding is formed from a single spiral. In practice, at least one turn is located at each of the end zones of the portion to be lined, so as to obtain a watertight transverse weld of the line to the body.

[0015] For example, the winding may be formed of at least two spirals connected by a straight portion extending substantially parallel to a longitudinal axis of the portion to be lined, each spiral being positioned at an end zone of the portion to be lined and being formed of one or more turns, for example three turns, and the straight portion being intended to be located at the longitudinal opening of the liner. Thus, it is possible to simultaneously perform transverse and longitudinal welds. The winding may also comprise one or more intermediate spirals between the two spirals positioned at the end zones of the portion to be lined.

[0016] According to another variant, the winding is formed of at least two spirals independent of each other, at least each end zone of the portion to be lined being provided with one of the two spirals and each spiral being formed of one or more turns, for example three turns. The winding may also comprise one or more independent intermediate spirals arranged between the two spirals positioned at the end zones of the portion to be lined. Thus, the winding is produced with several electro-welding wires, the ends of each spiral thus having to be connected to an electrical source. In other words, the spirals are connected so as to form a parallel circuit.

[0017] Preferably, the turns of each spiral are contiguous, i.e. adjacent turns touch but do not cross each other, and the ends of the winding or each spiral to be connected to a power supply are spaced at least a predefined distance apart, to avoid a short circuit.

[0018] In practice, the body may have a circular, square, triangular or other cross-section. For example, the body may be cylindrical. The invention may in particular be implemented for repairs on civil engineering structures, such as bridges with external prestressing, or on steam generator conduits of pressurized water nuclear reactors, or on fluid distribution pipes made of thermoplastic material.

[0019] Advantageously, the body can be made of high-density polyethylene (HDPE), polyurethane, polyvinyl chloride (PVC), polyamide or based on ABS-type polymers.

[0020] The invention also relates to a repair or reinforcement kit, by lining a hollow or solid body having a defective area, comprising at least: one or more sections of wires to be electro-welded, each wire to be electro-welded being formed of at least one electric wire coated in a sheath of thermoplastic material similar to that of said body; a preformed jacket having a section of shape similar to that of the body and being of length equal to that of the portion to be lined, said preformed jacket having an opening extending over its entire length, and being made of thermoplastic material similar to that of said body, the preformed jacket further comprising at least two vents, namely an injection vent and an outlet vent. Brève description des figures

[0021] Other characteristics and advantages of the invention will emerge clearly from the description given below, for information purposes only and in no way limiting, with reference to the appended drawings, in which: There figure 1 is a schematic representation of an electro-welding wire and a preformed jacket for repairing a conduit according to one embodiment. The figure 2 is a diagram showing the main steps of repairing the jacket and electro-welding according to one embodiment. The figure 3A is a schematic representation of a winding of electro-welding wires according to a variant. The figure 3B is a schematic representation of a winding of electro-welding wires according to another variant. The figure 4 is a schematic representation of a winding of electro-welding wires according to another variant. The figure 5A is a schematic representation of a winding of electro-welding wires according to another variant. The figure 5B is a schematic representation of a winding of electro-welding wires according to another variant. The figure 6 is a schematic representation of a conduit after repair by lining. The figure 7 is a schematic representation of a portion of a conduit covered by a preformed repair jacket incorporating two vents, according to one embodiment. The figure 8 is a schematic representation of a portion of a conduit covered by a preformed repair jacket incorporating two vents, according to another embodiment. The figure 9 is a schematic representation of a portion of a conduit covered by a preformed repair jacket incorporating three vents, according to another embodiment. Mode(s) de réalisation de l'invention

[0022] In reference to the figure 1 , a repair or reinforcement kit, by lining a body 3 hollow or solid, for example a cylindrical conduit, with a defective area 30, consists of at least one or more sections of wires to be electro-welded 1 and a shirt 2 preformed.

[0023] Each electro-welding wire 1 is formed of at least one electric wire 10 wrapped in a sheath 11 made of thermoplastic material similar to that of the conduit to be lined. The wire 3 electro-welding may in particular be in the form of a flexible thermoplastic rod, for example of approximately 5 mm in diameter, incorporating several electric wires wound inside a sheath of thermoplastic material of composition similar to that of the body 3 or at least the defective area 30.

[0024] The shirt 2preformed has a section of similar shape to that of the conduit and is of length L equal to that of the portion to be lined. The shirt 2 preformed has an opening 20 longitudinal extending along the entire length L of the shirt 2, and is made of thermoplastic material of similar composition to that of the conduit.

[0025] In reference to the figure 2 , a method of repairing or reinforcing by lining the conduit 3 according to one embodiment, comprises: the delimitation 40 on the outer surface of the duct 3 of a portion to be lined 31 including the defective area 30 ; realization 41 of a winding with at least one wire to be electro-welded 1 around the duct on the portion to be lined 31 ; positioning 42 of the shirt 2 preformed around the portion to be lined 31; realization 43 electro-welding of the shirt 2 to the conduit 3 by applying an electric current to the winding for a predefined duration, and progressively tightening the jacket 2 on the duct 3 during electro-welding.

[0026] Different examples of electrowelding wire winding patterns are illustrated in figures 3A à 5B .

[0027] On the figure 3A , an electro-welding wire is wrapped around the area to be lined 31 The winding is notably formed of two spirals 14a, 14b connected by a substantially straight portion 13c extending longitudinally along a longitudinal axis X of the portion to be lined 31. Each of the spirals 13a, 13b is positioned at an end zone 31a, 31b of the portion to be lined 31 and is formed of one or more turns 130. The right portion13c is positioned to be preferably located at the opening 30 longitudinal of the shirt 3. This makes it possible to simultaneously perform transverse and longitudinal welds. In this variant, the electrical connection is made at both ends. 131a And 131b. On the figure 3B , the winding may also include an intermediate spiral 13d between the two spirals 13a And 13b and connected by substantially straight portions 13c And 13d.

[0028] On the figure 4 , an electro-welding wire is wrapped around the area to be lined 31 to form a single spiral 14, and electro-welding is carried out by connecting the ends 141, 142 of the spiral 14 to a power supply.

[0029] On the figure 5A , the winding is formed from a first spiral 15aand a second spiral 15b independent of the first spiral 15a. The first spiral 15a is positioned at the level of a first end zone 31a of the portion to be lined 31, and the second spiral 15b is positioned at a second end zone 31b of the portion to be lined 31. The first and second spirals 15a, 15b are each formed of one or more turns. In this variant, the electrical connection is made at the ends 151a, 152a, 151b And 151b of each of the first and second spirals 15a, 15b. Furthermore, as illustrated in the figure 5B , depending on the length of the liner, it is also possible to provide one or more intermediate spirals 15c.

[0030] On the figure 6 , the jacket is positioned to cover the winding and the area to be jacketed and electro-welding of the jacket 2to the body 3 is achieved by applying an electric current to the winding for a predefined duration, accompanied by a progressive tightening of the jacket 2 on the body 3, in order to fuse the electro-welding wire to the jacket and the body to ensure adhesion of the different parts to each other and a watertight seal for the whole.

[0031] In practice, after the transverse electro-welding step, it is also possible to carry out a longitudinal electro-welding step via an electro-welding rod positioned at the opening. 20 of the shirt 2 to make a seal 200 of this opening.

[0032] Finally, to allow the injection of a protective petroleum wax-based product or to allow the injection of pressure in order to test the tightness of the repair, the preformed jacket is advantageously provided with at least two vents, for example two vents 5a-5b ( figures 7 And 8 ) or for example three vents 5a-5c ( figure 9 ), each acting as an injection vent or an outlet vent. The number of vents distributed along the jacket makes it possible to reduce the lengths to be injected. In addition, as mentioned above, depending on the length of the portion of the conduit 3 to be repaired, the winding can be formed from two independent spirals 15a-15b ( figure 7 ) or several independent spirals 15a-15c ( figure 8 ).

[0033] The solution of the present invention is particularly suitable for repairing a cylindrical conduit with a diameter ranging from a few centimeters to several meters in diameter. Similarly, the preformed liner used can have a thickness of a few millimeters and a length ranging from a few centimeters to several meters. In addition, the liner can be made from tube, plate or film, and includes injection vents regardless of its length or thickness.

[0034] The parameters relating to the duration of electro-welding, the voltages and currents to be applied depend on the characteristics of the electro-welding wire generally provided by the manufacturer of the electro-welding wire, the dimensions of the jacket, the winding pattern and the thermoplastic material.

Claims

1. Method for repairing or reinforcing, by lining a hollow or solid body (3) having a defective area (30), comprising: - delimitation (40) on the outer surface of the body (3) of a portion to be lined (31) including the defective area (30), said body (3) being a weldable thermoplastic material; - production (41) of at least one winding of an electro-welding wire (1) around said body (3) on the portion to be lined (31), the electro-welding wire (1) being formed of at least one electrically conductive wire (10) coated in a sheath (11) made of thermoplastic material similar to that of said body (3);- positioning (42) a preformed jacket (2) around the portion to be lined (31), said preformed jacket (2) having a section of similar shape to that of the body (3) and being of length (L) equal to that of the portion to be lined (31), said preformed jacket (2) having an opening (20) extending over its entire length, and being made of thermoplastic material similar to that of said body (3), the preformed jacket (2) further comprising at least one injection vent (5a) and one outlet vent (5b); - carrying out (43) the electro-welding of the jacket (2) to the body (3) by applying an electric current to the winding for a predefined duration, simultaneously with a progressive tightening of the jacket (2) on the body (3).; 2. Repair method according to claim 1, wherein the closure of the opening (20) is obtained by longitudinal electro-welding of an electro-welding rod or via winding.

3. Repair method according to claim 1, in which the winding is formed of a spiral (14), and at least one turn is located at each of the end zones of the portion to be lined, so as to obtain a sealed transverse weld of the lined to the body.

4. Repair method according to claim 3, wherein the winding is formed of at least two spirals (13a, 13b) connected by a straight portion (13c) extending substantially parallel to a longitudinal axis (X) of the portion to be lined (31), each spiral (13a, 13b) being positioned at one end of the portion to be lined (31) and being formed of one or more turns, and the straight portion (13c) being intended to be located at the longitudinal opening (20) of the liner (2).

5. Repair method according to claim 3, in which the winding is formed of at least two spirals (15, 15b) independent of each other, at least each end zone (31a, 31b) of the portion to be lined (31) being provided with one of the two spirals (15a, 15b) and each spiral being formed of one or more turns.

6. Repair method according to claim 5, wherein the winding further comprises one or more independent intermediate spirals (15c) arranged between said two spirals (15a, 15b).

7. Repair method according to one of claims 1 to 6, in which the turns of each spiral are joined.

8. Repair method according to one of claims 1 to 7, in which the body (3) is a conduit in which external prestressing cables or strands present in a bridge pass.

9. Repair or reinforcement kit, by lining a hollow or solid body (3) having a defective area (30), comprising at least: - one or more wires (1) to be electro-welded, each wire to be electro-welded being formed of at least one electrically conductive wire (10) coated in a sheath (11) made of thermoplastic material similar to that of said body (3); - a preformed jacket (2) having a section of similar shape to that of the body (3) and being of length equal to that of the portion to be lined (31), said preformed jacket (2) having an opening (20) extending over its entire length, and being made of thermoplastic material similar to that of said body (3), the preformed jacket (2) further comprising at least one injection vent (5a) and one outlet vent (5b).