Pressurized leakage stopping method suitable for gas leakage of high-voltage switch flange gap

Abstract

The invention relates to an under-pressure leaking stoppage method suitable for gas leakage of a high-voltage switch flange gap, and belongs to the technical field of leaking stoppage of high-voltage switch equipment.The method comprises the steps that the surface of a high-voltage switch leakage flange is polished and cleaned; the leakage flange and the peripheries of the air chamber cylinders on the two sides of the leakage flange are wrapped with elastic sealing layers; and winding and curing the high-strength pressure-resistant layer. Through the composite design of elastic buffering, sealing piece pressing, high-strength enhanced pressure resistance and multi-ring pressing, reliable sealing under the high-pressure working condition is achieved.

Description

Technical Field

[0001] This invention relates to the field of sealing and plugging technology for high-voltage electrical equipment, specifically to a pressurized sealing method for gas leakage in the gap of high-voltage switch flanges. Background Technology

[0002] Sulfur hexafluoride (SF6) gas possesses excellent insulation and arc-extinguishing properties, and is widely used in 10-500kV high-voltage switchgear. The flange connections of high-voltage switches are high-risk areas for SF6 gas leakage: after long-term operation, the flange sealing surface is prone to deterioration in sealing performance due to vibration, corrosion, and aging; or, during installation, loose sealing surfaces or uneven bolt preload can also cause SF6 gas leakage.

[0003] SF6 gas is a potent greenhouse gas; leaks not only pollute the environment but also reduce the insulation and arc-extinguishing performance of high-voltage switches, potentially causing equipment failures and affecting the safe and stable operation of the power system. Existing leak-sealing technologies have many shortcomings: (1) The traditional method requires disassembling the switch flange to replace the gasket, which is complicated, time-consuming, and requires power outage, affecting the reliability of power supply; (2) Emergency sealing often uses a single sealing ring or wrapping tape, which lacks sufficient clamping force and structural strength. It is prone to failure under high pressure (usually 0.6-0.8MPa) conditions and has poor sealing durability. (3) Some leak sealing solutions use welding to seal the flange body, which is easy to damage the flange body and poses a fire risk. They are not suitable for live-line work scenarios. (4) Existing clamp-type leak sealing devices are mostly single-point or a few clamps for tightening, resulting in uneven pressure distribution. It is difficult to achieve full fit of the sealing surfaces on both sides of the flange, and the risk of leakage is still relatively high.

[0004] Therefore, there is an urgent need for an SF6 gas sealing technology that requires no equipment disassembly, provides reliable and long-lasting sealing, withstands high pressure, and is suitable for live-line work, in order to solve the problem of leakage in the flange gap of high-voltage switches. Summary of the Invention

[0005] To address the technical problems of existing methods for sealing SF6 gas leaks in high-voltage switch flanges, such as "complex disassembly, poor sealing durability, poor high-pressure resistance, and cumbersome operation," this invention provides a pressurized sealing method suitable for gas leaks in the gaps of high-voltage switch flanges.

[0006] A pressurized leak sealing method suitable for gas leakage in high-voltage switch flange gaps. It includes the following steps: S1: Grind and clean the surface of the high-voltage switch leakage flange; S2: An elastic sealing layer is wrapped around the outer periphery of the leakage flange and the gas chamber cylinders on both sides, and the outer peripheral surface of the leakage flange and the outer peripheral surface of the gas chamber cylinders on both sides are in close contact with the elastic sealing layer without gaps. S3: At least one sealing element is installed on the periphery of the elastic sealing layer and on both sides of the leakage flange. The first sealing element, the second sealing element, etc. are installed on both sides with the leakage flange as the center. Each sealing element surrounds the outer peripheral surface of the gas chamber cylinder and fits against the outer surface of the elastic sealing layer without gap. The central axis of each sealing element coincides with the axis of the gas chamber cylinder. S4: Wrap a high-strength pressure-resistant layer and cure; A high-strength pressure-resistant layer material is wrapped around the outer edge of the elastic sealing layer. The elastic sealing layer and the high-strength pressure-resistant layer, as well as the layers of the high-strength pressure-resistant layer material, are bonded and fixed with adhesive. The adhesive layer is then left to cure initially.

[0007] Furthermore, it also includes the following steps: S5: Sealing test; Perform leakage detection on the periphery of the leaking flange to test whether the leakage rate meets the engineering requirements. If not, proceed to the next step. S6: Remove the high-strength pressure-resistant layer, elastic sealing layer and fasteners, and repeat steps S1 to S6 until the leakage rate meets the engineering requirements.

[0008] Furthermore, in S1, the surface roughness Ra of the leaking flange after grinding is ≤3.2μm.

[0009] Furthermore, the sealing material described in S3 is made of fluororubber or perfluoroelastomer, which has the characteristics of being resistant to SF6 gas corrosion and has a Shore hardness of 75 to 85 HA.

[0010] Furthermore, the elastic sealing layer is made of latex bandage material.

[0011] Furthermore, the high-strength pressure-resistant layer material is made of carbon fiber cloth or high-strength metal wire mesh.

[0012] Furthermore, at least one sealing element is installed on the periphery of the elastic sealing layer and on both sides of the leakage flange. With the leakage flange as the center, the first sealing element, the second sealing element, and so on are installed on both sides. At least the first sealing element is equipped with a first fastener to press the first sealing element into the elastic sealing layer.

[0013] Furthermore, multiple fasteners are installed around the high-strength pressure-resistant layer material to tightly fix the high-strength pressure-resistant layer, elastic sealing layer and sealing element to the outer peripheral surface of the switch chamber cylinder. The fasteners provide radial clamping force to the cylinder.

[0014] Furthermore, the outermost end of the elastic sealing layer or fastener is fixed to the gas chamber cylinder by adhesive.

[0015] Furthermore, the fastener is a clamp, which includes a high-strength arc-shaped clamp body, connecting bolts and pressure adjusting nuts, and an arc-shaped pad adapted to the high-strength pressure-resistant layer is provided on the inner side of the clamp body.

[0016] This invention achieves reliable sealing under high-pressure conditions through a composite design of "elastic buffer + sealing element compression + high-strength enhanced pressure resistance + multi-ring uniform compression".

[0017] The elastic sealing material wrapping layer and the seals installed on both sides utilize the elastic deformation capability of the elastic sealing material to fill the tiny gaps between the flange and the reinforced pressure-resistant layer. In case of leakage, it acts as a buffer and offsets the impact of high-voltage switchgear vibration on the seal.

[0018] When two seals are installed on each side of the leaking flange, a "double-sided double-channel" sealing barrier is formed, which expands the sealing contact area and improves the sealing redundancy.

[0019] The high-strength pressure-resistant layer, after being wound, forms a rigid pressure-resistant layer that constrains the internal sealing structure and prevents the sealing layer from deforming and failing under high pressure due to air leakage. When carbon fiber cloth is used as the high-strength pressure-resistant material, it also has the characteristics of high strength, high pressure resistance, and corrosion resistance, making it suitable for harsh environments.

[0020] The tightening of the radial fixing parts of the gas chamber cylinder and the sealing parts around the elastic sealing layer on both sides of the leakage flange ensure that the elastic sealing layer is tightly fitted to the outer circumferential surface of the flange cylinder, and also ensure that the pressure of the reinforced pressure-resistant layer is uniform, avoiding leakage caused by insufficient local pressure. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the leak-sealing method of the present invention; Figure 2 This is one embodiment of the present invention; Figure 3 This is a second embodiment of the present invention; Figure 4 This is the third embodiment of the present invention.

[0022] Figure 2-4 In the middle, 1. Fasteners, 2. Seals, 3. High-strength pressure-resistant layer, 4. Elastic sealing layer, 5. Flange, 6. Gas chamber shell of GIS switchgear, a. Flange leakage surface. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer and more understandable, the technical solutions of the embodiments of this invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0024] A live leak sealing method for gas leakage in high-voltage switch flange gaps includes the following steps: S1: Grind and clean the surface of the high-voltage switch leakage flange 5; S2: An elastic sealing layer 4 is wrapped around the outer periphery of the leakage flange 5 and its two sides, and the outer peripheral surface of the gas cylinder on both sides of the leakage flange 5 is in close contact with the elastic sealing layer 4 without gaps. S3: At least one sealing element 2 is installed on each side of the outer periphery of the elastic sealing layer 4 and the two sides of the leakage flange 5. The first sealing element, the second sealing element, etc. are installed on both sides with the leakage flange 5 as the center. Each sealing element surrounds the outer peripheral surface of the gas chamber cylinder 6 and is in close contact with the outer surface of the elastic sealing layer without gap. The central axis of each sealing element coincides with the axis of the gas chamber cylinder 6. S4: Wrap high-strength pressure-resistant layer 3 and cure; A high-strength pressure-resistant layer material is wrapped around the outer periphery of the elastic sealing layer 4. The elastic sealing layer 4 and the high-strength pressure-resistant layer 3 are bonded and fixed with adhesive between the layers of the high-strength pressure-resistant layer material, and the adhesive layer is allowed to cure initially by standing.

[0025] It also includes the following steps: S5: Sealing test; Perform a leak detection test on the periphery of the leaking flange 5 to test whether the leakage rate meets the engineering requirements. If not, proceed to the next step. S6: Remove the high-strength pressure-resistant layer 3, the elastic sealing layer 4, and the fastener 1, and repeat steps S1 to S6 until the leakage rate meets the engineering requirements.

[0026] The surface of the leaking flange 5 includes the outer peripheral surface of the flange 5 where the leak occurs and the outer peripheral surface of the gas chamber 6 near the two end faces of the flange 5. When a leak occurs, the leaking gas seeps out from the flange leak gap a.

[0027] In one embodiment, S1 can specifically be to grind the outer peripheral surface of the leakage flange 5 and the outer peripheral surface of the gas chamber cylinders 6 on both sides to smooth them, remove oil stains, rust and aged seal residue, clean them thoroughly and let them dry.

[0028] The cleaning process can be achieved using specialized cleaning agents, such as a metal paint remover and a metal rust remover.

[0029] In S1, the surface roughness Ra of the leaking flange 5 after grinding is ≤3.2μm, ensuring the tightness of the elastic sealing layer 4 with the outer circumferential surface of the flange 5 and the outer circumferential surface of the gas chamber cylinder 6 on both sides.

[0030] In one embodiment, such as Figure 1 , Figure 2 and Figure 3 The elastic sealing layer 4 wraps around the leakage flange 5 and the gas chamber cylinders 6 on both sides, and the elastic sealing layer 4 is in close contact with the outer peripheral surface of the leakage flange 5 and the outer peripheral surface of the gas chamber cylinders on both sides without gaps. To ensure airtightness, the elastic sealing layer 4 can be glued to the outer peripheral surface of the leakage flange 5 and the outer peripheral surface of the gas chamber cylinders 6 on both sides.

[0031] In one embodiment, the elastic sealing layer 4 is made of latex bandage.

[0032] In one embodiment, the elastic sealing layer 4 is used to seal and wrap the leaking flange 5 with an elastic strip material. The elastic strip material is kept taut during the winding process, and the overlap width of adjacent elastic strip materials is not less than 1 / 2 of the bandwidth.

[0033] In one embodiment, such as Figure 1 A sealing element 2 is installed on each side of the leakage flange 5, around the elastic sealing layer 4. In one embodiment, such as Figure 2 Two sealing elements 2 are installed on each side of the leakage flange 5 around the elastic sealing layer 4. The first sealing element and the second sealing element are respectively located on both sides of the leakage flange 5 as the center. A preset width interval is set between the second sealing element and the first sealing element.

[0034] Figure 1 and Figure 2 In the middle, each sealing element surrounds the outer circumference of the air chamber cylinder 6 and is in close contact with the outer surface of the elastic sealing layer 4 without gaps, and the central axis of each sealing element coincides with the axis of the air chamber cylinder 6; The sealing element 2 can be a sealing ring or a sealing strip.

[0035] The sealing element 2 is made of fluororubber or perfluoroelastomer, which has the characteristics of being resistant to SF6 gas corrosion and has a Shore hardness of 75 to 85 HA.

[0036] In one embodiment, such as Figure 1 , Figure 2 and Figure 3 At least the first seal is fitted with a first fastener 1 around its periphery to press the seal 2 against the elastic sealing layer 4. Figure 2 In the middle, a second fastener 1 is also installed around the second seal. The first fastener and the second fastener can be the same fastener or different fasteners, without specific restrictions. Figure 1 and Figure 2 In the middle, both the second fastener and the second fastener are clamps.

[0037] In one embodiment, such as Figure 3 The outermost end of the elastic sealing layer 4 or the fastener 1 is also fixed to the air chamber cylinder 6 by adhesive.

[0038] In one embodiment, such as Figure 1 and Figure 2 A high-strength pressure-resistant layer 3 is wrapped around the outer periphery of the elastic sealing layer 4 and the sealing element 2.

[0039] In one embodiment, the high-strength pressure-resistant layer material is made of carbon fiber cloth or high-strength metal wire mesh. Any material possessing high strength and pressure resistance is acceptable; no specific limitations are imposed.

[0040] In one embodiment, the adhesive is an epoxy resin, a neoprene rubber adhesive, or a cyanoacrylate adhesive.

[0041] In one embodiment, such as Figure 1 and Figure 2 Multiple fasteners 1 are installed around the high-strength pressure-resistant layer material to tightly fix the high-strength pressure-resistant layer 3, the elastic sealing layer 4 and the sealing element 2 to the outer peripheral surface of the switch chamber cylinder. The fasteners 1 provide radial clamping force to the cylinder.

[0042] In one embodiment, such as Figure 1 and Figure 2 The fastener 1 is installed on the periphery of the high-strength pressure-resistant layer 3. At least one fastener is provided on each side of the leakage flange. The fourth fastener presses against the periphery of the first seal and tightens it. The fastener 1 provides radial clamping force. Figure 2 In the middle, the fourth and second fasteners can also be set in the gap between the first and second sealing rings, and around the high-strength pressure-resistant layer material; In one embodiment, a fourth and third fastener is also provided, which is installed on the outer periphery of the pressure-resistant layer material outside the second sealing ring; similarly, the fourth and third fastener is used to provide radial clamping force.

[0043] In one embodiment, the fastener 1 is a clamp, which includes an arc-shaped clamp body, a connecting bolt and a pressure adjusting nut, and an arc-shaped pad adapted to the high-strength pressure-resistant layer 3 is provided on the inner side of the clamp body.

[0044] In one embodiment, the arc-shaped clamp body of the clamp is made of high-strength alloy steel.

[0045] In one embodiment, the pad is made of silicone rubber with an anti-slip texture on the surface, and the pad has a thickness of 3-5 mm.

[0046] The fastening clamps are tightened by adjusting the clamp tension using connecting bolts. Preferably, the tightening pressure of each clamp is in the range of 2–3 MPa.

[0047] When tightening fastener 1 in S5, a torque wrench is used to control the torque to ensure sufficient tightening force. Generally, the torque value is 80 to 120 N·m.

[0048] In one embodiment, the fastener 1 may also be a clamp, American hose clamp, European hose clamp, heavy-duty hose clamp, strap, etc.

[0049] In one embodiment, in step S5, the leak detection is performed by pressure testing or by using a leak detector.

[0050] The above embodiments can be applied individually or in combination, provided that they are feasible.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A live leak sealing method for gas leakage in high-voltage switch flange gaps, characterized in that, It includes the following steps: S1: Grind and clean the surface of the high-voltage switch leakage flange; S2: An elastic sealing layer is wrapped around the outer periphery of the leakage flange and the gas chamber cylinders on both sides, and the outer peripheral surface of the leakage flange and the outer peripheral surface of the gas chamber cylinders on both sides are in close contact with the elastic sealing layer without gaps. S3: At least one sealing element is installed on the periphery of the elastic sealing layer and on both sides of the leakage flange. The first sealing element, the second sealing element, etc. are installed on both sides with the leakage flange as the center. Each sealing element surrounds the outer peripheral surface of the gas chamber cylinder and fits against the outer surface of the elastic sealing layer without gap. The central axis of each sealing element coincides with the axis of the gas chamber cylinder. S4: Wrap a high-strength pressure-resistant layer and cure; A high-strength pressure-resistant layer material is wrapped around the outer edge of the elastic sealing layer. The elastic sealing layer and the high-strength pressure-resistant layer, as well as the layers of the high-strength pressure-resistant layer material, are bonded and fixed with adhesive. The adhesive layer is then left to cure initially.

2. The method for pressurized sealing of gas leakage in the gap of a high-voltage switch flange according to claim 1, characterized in that, It also includes the following steps: S5: Sealing test; Perform leakage detection on the periphery of the leaking flange to test whether the leakage rate meets the engineering requirements. If not, proceed to the next step. S6: Remove the high-strength pressure-resistant layer, elastic sealing layer and fasteners, and repeat steps S1 to S6 until the leakage rate meets the engineering requirements.

3. A live leak sealing method for gas leakage in high-voltage switch flange gaps according to claim 1, characterized in that, In S1, the surface roughness Ra of the leaking flange after grinding is ≤3.2μm.

4. A live leak sealing method for gas leakage in high-voltage switch flange gaps according to claim 1, characterized in that, The sealing material described in S3 is fluororubber or perfluoroelastomer, which has the characteristics of being resistant to SF6 gas corrosion and has a Shore hardness of 75 to 85 HA.

5. A live leak sealing method for gas leakage in high-voltage switch flange gaps according to claim 1 or 4, characterized in that, The elastic sealing layer is made of latex bandage material.

6. A live leak sealing method for gas leakage in high-voltage switch flange gaps according to claim 1, characterized in that, The high-strength pressure-resistant layer material is made of carbon fiber cloth or high-strength metal wire mesh.

7. A live leak sealing method for gas leakage in high-voltage switch flange gaps according to claim 1, characterized in that, At least one sealing element is installed on each side of the leaking flange and around the elastic sealing layer. The first sealing element, the second sealing element, and so on are installed on both sides of the leaking flange as the center. At least the first sealing element is fitted with a first fastener to press the first sealing element into the elastic sealing layer.

8. A live leak sealing method for gas leakage in high-voltage switch flange gaps according to claim 1 or 7, characterized in that, Multiple fasteners are installed around the high-strength pressure-resistant layer material to tightly fix the high-strength pressure-resistant layer, elastic sealing layer and sealing element to the outer peripheral surface of the switch chamber cylinder. The fasteners provide radial clamping force to the cylinder.

9. A live leak sealing method for gas leakage in high-voltage switch flange gaps according to claim 1 or 7, characterized in that, include: The outermost end of the elastic sealing layer or fastener is fixed to the gas chamber cylinder by adhesive.

10. A live leak sealing method for gas leakage in high-voltage switch flange gaps according to claim 1, characterized in that, The fastener is a clamp, which includes a high-strength arc-shaped clamp body, connecting bolts and pressure adjusting nuts, and an arc-shaped pad adapted to the high-strength pressure-resistant layer is provided on the inner side of the clamp body.

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