DEVICE FOR ENCLOSING GAS LEAKS FOR AN INTERFACE BETWEEN AN INSULATING CONE OR A FLAT GASKET AND A FLANGE

Description

1. Scope of the invention

[0001] The field of the invention is that of installations containing a gas under pressure.

[0002] More specifically, the invention relates to a device for containing a gas leak at the interface between an intermediate part, such as an insulating cone or a flat gasket, sandwiched between two flanges, and one of these flanges.

[0003] The invention finds particular application for metal-enclosed electrical substations, also called shielded substations, and more generally for sections of piping intended to contain a pressurized gas equipped with an insulating cone, and for natural gas pipelines. 2. State of the art

[0004] Metal-enclosed electrical substations (also known by the acronym GIS for "Gas Insulated Switchgear" in English) consist of an assembly of independent compartments containing a pressurized insulating gas, most often SF6.

[0005] Each compartment is connected to the next by means of assembly flanges between which an insulation cone is inserted to support the electrical conductors mounted inside the compartments.

[0006] With the aging of armored posts, a progressive appearance of insulating gas leaks is observed at the level of the compartment assembly flanges and among other places at the interfaces between the insulating cones and the flanges.

[0007] In addition to the strong impact these leaks have on the greenhouse effect, they result in a drop in internal pressure in the compartments of the armored post, which if it reaches a minimum pressure threshold leads to the compartments being shut down for safety.

[0008] This securing of the compartments causes a network outage, which is very detrimental to the operation of a shielded station.

[0009] This is why maintenance operations are currently carried out regularly on the compartments of the shielded substations, in order to monitor and compensate for any pressure drops or reduce leaks, with the aim of preventing the risk of a power outage. These ongoing maintenance operations represent a significant expense for the substation operator at the end of the year.

[0010] To try to remedy the problem of sealing the compartments of armored posts, it has been proposed to seal the points of leakage with sealing paste or resins.

[0011] One drawback of this sealing technique is that the paste or resin must be applied regularly and precisely around the flanges, which is all the more complex, long and tedious as the contour of the flanges may be at least partly inaccessible.

[0012] Another drawback of this known technique is that the application must be renewed regularly.

[0013] There is also a risk of damage to the insulating cone during a sealing operation.

[0014] Finally, a sealing operation on a compartment of an armored post can present a risk to personnel working on the armored post due to induction phenomena.

[0015] Document WO2013 / 149749 A1 describes a leak-proof cover consisting of two semi-cylindrical shells that is mounted around the assembly flanges of two tubes containing a pressurized gas, and which allows for the containment of gas leaks occurring at the junction between the flanges. Document FR3 043 267 A1 also describes a cover of the same type adapted for mounting around flanges connecting tubes of different diameters.

[0016] Document US2014 / 0311583 A1 describes a device for removing flanges without releasing gas into the atmosphere. This device, consisting of two hinged cylindrical half-shells, is placed around the flanges and has an opening to which a vacuum pump is connected to collect the gas that escapes when the flanges are loosened.

[0017] Document WO 2017 / 162660 A1 describes a sealed, ring-shaped fitting for connecting two casings of a gas-insulated electrical appliance. Document JP2005269684A also discloses a similar fitting. 1. Objectives of the invention

[0018] The invention therefore aims in particular to overcome the disadvantages of the prior art mentioned above.

[0019] More specifically, the invention aims to provide an effective and cost-effective technique for containing a gas leak. Another objective of the invention is to provide such a technique that is simple to implement.

[0020] The invention also aims to provide a technique for containing a gas leak at the interface between an intermediate part and a flange which preserves the condition of the intermediate part.

[0021] Another objective of the invention is to provide such a technique which is safe for operators working on or near the area where the leak has occurred. 4. Description of the invention

[0022] These objectives, as well as others that will appear subsequently, are achieved using a containment device according to claim 1.

[0023] The invention thus proposes to cover a major part of the edge of the intermediate piece with a band of strapping to collect it in the internal housing of the collection enclosure.

[0024] In addition, the sealing of the containment device is ensured by a cord applied to both the annular band of strapping, the flanges and the lower portion of the collector, which is simple and quick to implement and, in the event that dismantling of the device is required, is easy to detach from the flanges.

[0025] Finally, thanks to the removable sealing means, which can be removed during the application of the sealing cord, the gas can escape through the light during the hardening of the cord, which prevents gas from opening a passage through the hardening cord and rendering the containment device ineffective.

[0026] It should be noted that, within the scope of the invention, the gas collection chamber can be secured to the strapping by gluing, welding, or any other known fastening technique. Furthermore, the collection chamber can extend substantially beyond the clasp and also over a substantial portion of the perimeter of the intermediate piece, without departing from the scope of the invention.

[0027] According to an advantageous embodiment of the invention, said annular strapping band is an open band having a first and a second end, in that said strapping means comprise a clasp connecting said first and said second end, and in that said internal housing is adapted to at least partially receive said clasp

[0028] The gas exit is thus limited to the junction area between the two ends of the strapping band, which are held together by the clasp.

[0029] In an advantageous embodiment of the invention, a containment device as described below comprises a first deformable annular band and a second deformable annular band intended to be mounted respectively on said first flange and on said second flange, or straddling said first flange and said intermediate piece and straddling said intermediate piece and said second flange, and said annular band of strapping being mounted on said first deformable annular band and said second deformable annular band and clamps said first deformable annular band against the edge of said first flange, or against the edge of the first flange and the outer edge of said intermediate piece, and said second deformable annular band against the edge of said second flange, or against the edge of the second flange and the outer edge of said intermediate piece.

[0030] By inserting protective deformable annular bands between the intermediate piece and the strapping means, the surface of the intermediate piece is prevented from being damaged and a guide is created towards the collection chamber for the gas.

[0031] It should be noted that to contain leaks in the joint plane between the intermediate piece and a flange, the deformable annular strips will be positioned only on the flanges, preferably at the edge of the intermediate piece, and to contain leaks at a leak resumption orifice, the deformable annular strips will be positioned straddling the intermediate piece and a flange.

[0032] Advantageously, said first deformable annular band and said second deformable annular band are made of a flexible or semi-rigid material.

[0033] This can include, in particular, annular bands made of EPDM (acronym for ethylene-propylene-diene monomer).

[0034] According to a particular aspect of the invention, said clasp is a toggle latch.

[0035] In a variant of this embodiment, it may be envisaged that the clasp is a screw-rack type clasp, such as used for non-perforated band clamps or includes a trunnion, said strapping means forming a trunnion collar.

[0036] According to the invention, said cord is formed of resin, preferably two-component polyurethane resin, resin-coated fabric or thermoformable, heat-shrinkable or electroformable material.

[0037] Preferably, the thickness of said cord is between 2 and 15 millimeters.

[0038] Advantageously, a containment device as described above includes a hood enveloping said enclosure and said sealing cord and means for attaching said hood to said flanges.

[0039] This protects the enclosure and the sealing cord from ultraviolet rays, salt or pollution and limits the risk of corrosion of the enclosure.

[0040] According to the invention, said collection enclosure has a light opening on one side into said inner housing and on the other side to the outside of said collector in its upper portion and means for removable closure of said light.

[0041] According to an advantageous aspect of the invention, said means for removable closure of said light include means for drawing out the gas stored in the housing of the enclosure.

[0042] This gas can therefore be recovered when its release into the atmosphere is not permitted, as is the case for example with SF6.

[0043] According to a particular embodiment of the invention, said first flange and said second flange having different outside diameters, the radial thicknesses of said first deformable annular band and of said second deformable annular band are adapted so that the outside diameter of said first deformable annular band is identical to the outside diameter of said second deformable annular band.

[0044] Deformable annular bands of different thicknesses are therefore planned to compensate for the difference in outside diameter between the two flanges.

[0045] In a particular embodiment of the invention, said first and second flanges are assembly flanges of two compartments of an electrical substation in a metallic enclosure and in that said intermediate piece is an insulating cone.

[0046] In a particular embodiment of the invention, said strapping means and said collection enclosure are formed as a single unit.

[0047] In a particular embodiment of the invention, said collection enclosure is fixed to said leak resumption orifice. 5. List of figures

[0048] Other features and advantages of the invention will become clearer upon reading the following description of two embodiments of the invention, given by way of simple illustrative and non-limiting examples, and the accompanying drawings, among which: there figure 1 is a perspective view of an example embodiment of a gas leak containment device according to the invention, mounted on the periphery of two assembly flanges for compartments of a metal-enclosed electrical substation, which enclose an insulating cone, the cover of which has been removed; figure 2is a cross-sectional view of the containment device shown with reference to the figure 1 ; there figure 3 is a sagittal cross-sectional view of the containment device shown with reference to the figure 1 ; there figure 4 is a perspective view of the containment system presented with reference to the figure 1 equipped with its hood; the figure 5 is a cross-sectional view of another example of an embodiment of a device for containing a gas leak at the outlet of a gas return orifice formed in an insulating cone according to the invention; the figure 6 is a cross-sectional view of a variant of the containment device shown with reference to the figure 5 ; there figure 7 is a perspective view of a third example of an embodiment of a gas leak containment device in which the strapping band and the collection chamber are formed as a single unit; the figure 8is a cross-sectional view of the device shown with reference to the figure 7 , carried out at the level of the gas collection enclosure. 6. Detailed description of the invention

[0049] We illustrated on the figure 1 , an example of an embodiment of a gas leak containment device 10 according to the invention, in a perspective view, without a protective cover.

[0050] The device 10 is mounted on the periphery of a first circular flange 21 (not visible on the figure 1 ) and a second circular flange 12 bolted together to assemble two compartments 13 and 14 of an electrical substation in a metal enclosure.

[0051] This device 10 covers the edge of the first flange 21 and the second flange 12 and the edge of an insulating cone 11 sandwiched between the two flanges 21 and 12, and having the same outside diameter as the flanges 21 and 12, the tip of which can be distinguished on the figure 1 .

[0052] We can see on the figure 1 the head of a gas collection chamber 15 emerging from the 10 mm thick two-component polyurethane cord 16 applied around the entire perimeter of the flange assembly 21, 12 and the insulating cone 11, and which forms the outer layer of the device 10.

[0053] As can be seen on the figure 2In a cross-sectional view AA of the device 10 at the position of the collection chamber 15, the collection chamber 15, in this particular embodiment of the invention, is formed by a body closed by a base 26, which defines an internal compartment 22 and has a collar 27 in its lower part. A hole has also been tapped in the base 26 of the chamber 15 to allow the gas to escape while the sealing bead 16 properly polymerizes after its application. This hole was then sealed with a sealing screw 28 to retain the gas inside the device 10.

[0054] The internal housing 22 of the collection enclosure 16 accommodates the upper part of a frog 23.

[0055] There figure 3is a sagittal cross-sectional view of the collection enclosure area, allowing for better distinction of the different parts of the toggle 23. This consists of a lever 31 mounted pivoting around the axis 32, the proximal end of which 33 is housed in a hook 34, which allows the two ends of an open annular strapping band 35 cut from a sheet of slender to be locked and the strapping band 35 to be fixed to the flanges 21 and 12.

[0056] In order not to damage the insulating cone 11, the lateral edges of the open annular band 35 rest on a first deformable annular band 24 and a second deformable annular band 25, mounted respectively on the edge of the first flange 21 and on the edge of the second flange 12, at the edge of the insulating cone 11. These shoring bands 24 and 25, while serving as supports for the open annular band 35, delimit an additional gas confinement volume between the insulating cone and the banding band 35.

[0057] The gas escaping from the compartments of the metal-enclosed electrical substation through the interface between the insulating cone 11 and the flanges 21 and 12 is thus directed towards the area of ​​the toggle 23, where it travels between the two superimposed ends of the packing strip to be collected in the internal housing 22 of the collection enclosure 15.

[0058] In this particular embodiment of the invention, the annular bands 24 and 25 are made of EPDM.

[0059] It should be noted that in this particular embodiment of the invention, the strapping band 35 does not cover the entire width of the deformable annular bands 24 and 25. This ensures proper diffusion of the polyurethane cord 16 along the bands 24 and 25 and the strapping band 35 and increases the surface area of ​​adhesion of the cord 35 with the annular bands 24 and 25.

[0060] Furthermore, the collection enclosure 15 is in this particular embodiment of the invention, fixed by gluing to the strapping band 35 by means of a polyurethane film which penetrates between the enclosure during the application of the sealing cord 16.

[0061] The external shape of the sealing cord 16 illustrated on the figures 1 to 3is that of this particular embodiment of the invention. Other external forms can of course be envisaged without departing from the scope of the invention.

[0062] In a variant of this particular embodiment of the invention, it may also be envisaged that the sealing cord is also applied to the assembly screws of the flanges 21 and 12.

[0063] We illustrated on the figure 4 , the device 10 equipped with its cover 41 in a perspective view.

[0064] This hood 41 is formed of two half-shells which are fixed, with additional nuts, onto the assembly screws of the flanges 21 and 12. It covers the sealing cord 16 and the collection enclosure 15 and protects them from ultraviolet, salt and pollution.

[0065] We have represented on the figure 5 a cross-sectional view of another example of an embodiment of a containment device 50 according to the invention.

[0066] This device 50 is mounted on the periphery of the assembly area of ​​two compartments 51 and 52 of a metal-enclosed electrical substation and covers two assembly flanges 53 and 54 enclosing an insulating cone 55 sandwiched between two pairs of coaxial joints 56 and 57.

[0067] The inner seal 56 and the outer seal 57 of these pairs of coaxial seals are separated by a space 58 opposite a leak recovery port 59 drilled in the insulating cone 55. This leak recovery port 59 consists of a horizontal hole 510 which opens on each side of the insulating cone 55 into one of the spaces 58 and a vertical hole 511, intersecting the hole 510, opening at the edge of the insulating cone 55. It allows the gas to be collected in a first enclosure 512 of the containment device 50, when a leak appears at an inner seal 56.

[0068] This collection enclosure 512 is mounted on a strapping band 513 closed by a toggle 517, which rests on two deformable annular bands 514 and 515 which it ensures the clamping against the edge of the flanges 53 and 54. A sealing plug 516 is also screwed into the head of this enclosure 512.

[0069] It should be noted that in this particular embodiment of the invention, the deformable annular bands 514 and 515 are mounted respectively astride the flange 53 and one edge of the insulating cone 55 and astride the other edge of the insulating cone and the flange 54, in order to block the passage to a leak which would appear at the level of an external joint 57.

[0070] To perfect the seal, a sealing cord 518 applied around the entire periphery of the flanges covers the edge of the flanges 53 and 54, the strapping band 513, the outer lateral edge and part of the outer face of the deformable annular bands 514 and 515 and the lower part of the collection enclosure 512.

[0071] In a variant of this particular embodiment of the invention illustrated in the figure 6 , it can also be provided that the base 61 of the collection enclosure 512 can be inserted into the vertical hole 511 of the leak resumption orifice 59.

[0072] THE figures 7 And 8 are an illustration of a variant of implementation of a device for containing a gas leak at the level of a leak resumption orifice, in a perspective view and in a cross-sectional view.

[0073] As can be seen on the figure 7, this containment device 70 according to the invention comprises a band collector 73 covered with a sealing cord 75, formed of two semi-circular half-collectors 73A and 73B assembled together in a hermetic manner by means of assembly tabs 74. In this particular embodiment of the invention, the gas collection enclosure is formed as a single unit with the half-collector 73A.

[0074] This device 70 allows leaks to be contained at the level of a leak recovery orifice 71 formed in an insulating cone 76 mounted between two flanges 77 and 78 between which two pairs of coaxial seals 79 have been inserted on each side of the insulating cone.

Claims

1. Device (10,50,70) for containing a gas leak at an interface between an intermediate part, such as an insulating cone (11,55,76) or a sealing gasket, and a first circular flange (21,53,77) or at a leak-off orifice (59,71) formed in an intermediate part, said intermediate part being enclosed between said first circular flange (21,53) and a second circular flange (12,54,78), the device comprising: - means for strapping a substantial portion of the edge of said intermediate part, the means comprising an annular strapping band (31,513,73); - a chamber (15,512) for collecting the escaping gas, which chamber is rigidly connected to said strapping means and has an internal recess (22) and an opening leading into said internal recess (22) and to the exterior of said collector (15,512), at the upper portion thereof, and means for removably closing said opening; - a sealing collar (16,518,75), said collar (16,518,75) at least partially covering said annular strapping band (31,513,73) all around said flanges (21,12,53,54,77,78) and surrounding at least the lower external portion of said collector (15, 512), characterized in that: - the sealing collar (16, 518, 75) is made of resin, preferably bi-component polyurethane resin, resin-coated fabric or thermoformable, heat-shrinkable or electroformable material, - the sealing collar (16, 518, 75) at least partially covers the edges of said flanges all around the flanges (21, 12, 53, 54, 77, 78).

2. Device for containing a gas leak according to claim 1, characterized in that said annular strapping band (31,513,73) is an open band having a first and a second end, in that said strapping means comprise a fastening that connects said first end and said second end and in that said internal recess (22) is capable of receiving said fastening at least in part.

3. Device for containing a gas leak according to either of claims 1 or 2, characterized in that it comprises a first deformable annular band (24,514) and a second deformable annular band (25,515) intended to be mounted respectively on said first flange (21,53) and on said second flange (12, 54), or to straddle said first flange (21, 53) and said intermediate part and to straddle said intermediate part and said second flange (12,54), and in that said annular strapping band (31,513,73) is mounted on said first deformable annular band (24,514) and said second deformable annular band (25,515) and clamps said first deformable annular band (24,514) against the edge of said first flange (21,53,77), or against the edge of the first flange (21,513,77) and the external rim of said intermediate part, and said second deformable annular band (25,515) against the edge of said second flange (12,54,78), or against the edge of the second flange (12,54,78) and the external rim of said intermediate part.

4. Device for containing a gas leak according to claim 3, characterized in that said first deformable annular band (24,514) and said second deformable annular band (25,515) are made of a non-rigid or semi-rigid material.

5. Device according to claim 2, characterized in that said fastening is a toggle latch (23,517).

6. Device according to any of claims 1 to 5, characterized in that the thickness of said collar (16,518,75) is between 2 and 15 millimeters.

7. Device according to any of claims 1 to 6, characterized in that it comprises a cover (41) surrounding said chamber (15,512) and said sealing collar (16,518,75) and means for fastening said cover (41) to said flanges (21,12,53,54,77,78).

8. Device according to claim 1, characterized in that said means for removably closing said opening comprise means for drawing off the gas stored in the recess of the chamber (15,512).

9. Device according to claim 3, characterized in that, with said first flange (21,53,77) and said second flange (12,54,78) having different external diameters, the radial thicknesses of said first deformable annular band (24,514) and of said second deformable annular band (25,515) are adapted so that the external diameter of said first deformable annular band (24,514) is identical to the external diameter of said second deformable annular band (25,515).

10. Device according to any of claims 1 to 9, characterized in that said first flange (21,53,77) and second flange (12,54,78) are flanges for assembling two compartments (13,14,51,52) of a metal-clad electrical substation, and in that said intermediate part is an insulating cone (11,55,76).

11. Device according to any of claims 1 to 10, characterized in that said strapping means (73) and said collection chamber (15,512) are formed as a single piece.

12. Device according to any of claims 1 to 11, characterized in that said collection chamber (15,512) is fastened to said leak-off orifice (59,71).