A sulfur hexafluoride fuse

Abstract

This utility model relates to fuses, specifically a sulfur hexafluoride (SF6) fuse; it includes a metallized fuse tube and a fusible element located inside it, characterized in that: both ends of the fusible element are connected to the two end faces of the metallized fuse tube; sealing gaskets are provided on both end faces of the metallized fuse tube, forming a sealed cavity between the two sealing gaskets and the metallized fuse tube; the sealed cavity is filled with SF6 gas as an arc-extinguishing medium; connecting terminals are sleeved on both ends of the metallized fuse tube, and the connecting terminals are electrically connected to the sealing gaskets. Compared with existing fuses, this fuse is lighter, occupies less space, the filling process is easier to quantify, and its structure is simpler, which helps to achieve automated production.

Description

Technical Field

[0001] This utility model relates to fuses, specifically to a sulfur hexafluoride fuse. Background Technology

[0002] A fuse, commonly known as a "fuse", is an overcurrent protection device widely used in power distribution and control systems, mainly for short-circuit or overload protection.

[0003] The mainstream thermal fuses on the market today consist of an insulating tube, terminals, a cover plate, a fusible element, and an arc-extinguishing medium, among other auxiliary materials. Their working principle is as follows: Under specified voltage conditions, current flows through the fusible element in the circuit. Utilizing the thermal effect of the current, when the heat accumulates to a certain level, the current sensing point (narrow section) of the fusible element melts and breaks within a specified time, thus safely disconnecting the fault current. The main function of the arc-extinguishing medium is to absorb the energy released by the arc after the fusible element breaks, ensuring that the energy released when the fuse operates does not overflow and harm other surrounding devices.

[0004] In mainstream thermal fuses on the market, the arc-extinguishing medium is mostly a mixture of quartz sand of different mesh sizes in a certain proportion, which is then filled into the insulating tube of the fuse. When the fuse operates, it extinguishes the electric arc and absorbs the arc energy. As the market demands increasingly smaller, lighter, and more consistent fuses, thermal fuses using quartz sand as the arc-extinguishing medium are struggling to meet the new market requirements due to their large size, heavy weight, and the difficulty in quantifying the uneven particle size distribution during quartz sand filling, which leads to inconsistent product quality.

[0005] For example, Chinese patent document CN118173424A discloses a high-reliability high-voltage fuse and its assembly method. The high-voltage fuse includes a tube with openings on both sides, a fusible element disposed within the inner cavity of the tube, a carrier disposed within the inner cavity of the tube for fixing the fusible element, end caps disposed on both sides of the carrier for electrical connection with the fusible element, and a sealing cap assembly disposed on the tube for covering the openings of the tube. The fusible element is spring-shaped, and the outer wall of the carrier has spiral grooves for the fusible element to be embedded. However, the fuse structure in this patent application is relatively complex, which is not conducive to automated production. Utility Model Content

[0006] The purpose of this invention is to solve the technical problem that the existing fuse structure is too complex and not conducive to automated production, and to provide a sulfur hexafluoride fuse.

[0007] To solve the above-mentioned technical problems, the technical solution provided by this utility model is as follows:

[0008] A sulfur hexafluoride fuse includes a metallized fuse tube and a molten body located inside it, wherein the two ends of the molten body are respectively connected to the two end faces of the metallized fuse tube.

[0009] Sealing gaskets are provided on both ends of the end face of the metallized fusion tube, and a sealing cavity is formed between the two sealing gaskets and the end face metallized fusion tube; the sealing cavity is filled with sulfur hexafluoride gas as an arc extinguishing medium.

[0010] Both ends of the end-face metallized fusion tube are fitted with connecting terminals, which are electrically connected to the sealing gasket.

[0011] Furthermore, the melt is Z-shaped, and both ends of the melt are connected to the two end faces of the end-face metallized melt tube, respectively.

[0012] Furthermore, the melt has multiple evenly distributed narrow sections; when a short-circuit current or overload current passes through the melt, the thermal effect of the short-circuit current or overload current melts the narrow sections of the melt and generates an electric arc, and sulfur hexafluoride gas acts as an arc-extinguishing medium to adsorb free electrons in the electric arc and extinguish the arc.

[0013] Furthermore, one of the sealing gaskets is equipped with an inflation valve. After sulfur hexafluoride gas is injected into the sealing cavity through the inflation valve, the sealing is achieved by spot welding.

[0014] Furthermore, one of the sealing gaskets is provided with two inflation valves of different lengths;

[0015] When sulfur hexafluoride gas is introduced into the sealed cavity through the longer filling valve, the air in the sealed cavity is discharged through the shorter filling valve; after the sealed cavity is filled with sulfur hexafluoride gas, both filling valves are sealed by spot welding.

[0016] Furthermore, the sealing gasket is fixed to the end face of the end-face metallized fusion tube by welding.

[0017] Furthermore, the pressure of the sulfur hexafluoride gas inside the sealed cavity is 0.1-10 MPa.

[0018] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0019] 1. The sulfur hexafluoride fuse provided by this utility model forms a sealed cavity inside the metallized fuse tube by setting sealing gaskets at both ends of the metallized fuse tube. The sealed cavity is then filled with sulfur hexafluoride gas as the arc-extinguishing medium. Since sulfur hexafluoride gas is a highly electronegative inert gas, it readily adsorbs free electrons to form large negative ions, weakening the collisional ionization process in the gas. It has high electrical insulation strength and excellent arc-extinguishing ability. Using sulfur hexafluoride gas as the arc-extinguishing medium of the fuse has advantages such as light weight, small volume, and easy quantification of the filling process. Compared with the fuse structure in the prior art, it is simpler and facilitates quantification and automated production.

[0020] 2. The sulfur hexafluoride fuse provided by this utility model has two charging valves of different lengths, one long and one short, which facilitates identification of the charging valve for charging and the charging valve for discharging air. Since the density of sulfur hexafluoride gas is greater than that of air, when sulfur hexafluoride gas is introduced into the sealed cavity through the longer charging valve, the air in the sealed cavity can be discharged through the shorter charging valve. This helps to improve the efficiency of charging sulfur hexafluoride gas into the sealed cavity and further improves the assembly efficiency of the fuse. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of an embodiment of the present utility model;

[0022] Figure 2 This is an exploded structural diagram of an embodiment of the present utility model;

[0023] Figure 3 This is a cross-sectional structural diagram of an embodiment of the present utility model;

[0024] Figure 4 This is another cross-sectional view of an embodiment of the present utility model;

[0025] Figure 5 This is a cross-sectional structural diagram of another embodiment of the present invention.

[0026] Explanation of reference numerals in the attached drawings: 1-End face metallized fusion tube, 2-End face, 3-Fuse, 4-Sealing gasket, 5-Connecting terminal, 6-Inflation valve, 7-Narrow section. Detailed Implementation

[0027] The technical solutions of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0028] like Figure 1 and Figure 2 As shown, a sulfur hexafluoride fuse is mainly used in power distribution systems and control systems, as well as in situations where there are stringent requirements for the size and quality of the fuse, for short-circuit protection and overload protection.

[0029] The sulfur hexafluoride fuse includes a metallized fuse tube 1 and a molten body 3 located inside it, with the two ends of the molten body 3 connected to the two end faces 2 of the metallized fuse tube 1 respectively.

[0030] In this embodiment, the end-face metallized fusion tube 1 is formed by providing metal end faces 2 at both ends of a non-conductive non-metallic tube; both end faces 2 of the end-face metallized fusion tube 1 are provided with sealing gaskets 4, which are made of metal, such as copper; both sealing gaskets 4 are fixed to the end faces 2 of the metallized fusion tube by laser welding; a sealing cavity is formed between the two sealing gaskets 4 and the end-face metallized fusion tube 1;

[0031] To ensure that the fuse can quickly extinguish the arc after the fuse element 3 melts following a short circuit or overload current, the sealed cavity is filled with sulfur hexafluoride gas as the arc-extinguishing medium. Sulfur hexafluoride gas is chosen as the arc-extinguishing medium because it is a highly electronegative inert gas that readily adsorbs free electrons to form large negative ions, thus weakening the collisional ionization process in the gas. It has high electrical insulation strength and excellent arc-extinguishing ability. Moreover, using sulfur hexafluoride gas as the arc-extinguishing medium makes the fuse lightweight and compact.

[0032] In order to enable the fuse to be used in power distribution systems and control systems to provide short-circuit and overload protection for power distribution systems and control systems, both ends of the end-face metallized fuse tube 1 are fitted with connecting terminals 5, and the connecting terminals 5 are electrically connected to the sealing gasket 4.

[0033] like Figure 3 As shown, in order to enable the two ends of the melt 3 to be connected to the two end faces 2 of the end face metallized melt tube 1 respectively, and to enable the melt 3 to fully contact the arc extinguishing medium in the end face metallized melt tube 1, the melt 3 is Z-shaped, and the two ends of the melt 3 are connected to the two end faces 2 of the end face metallized melt tube 1 respectively.

[0034] like Figure 2 and Figure 4 As shown, in order to enable the melt 3 to melt quickly after passing a short-circuit or overload current, the melt 3 is provided with a plurality of evenly distributed narrow sections 7; when the short-circuit current or overload current passes through the melt 3, the narrow sections 7 of the melt 3 are melted by the thermal effect of the short-circuit current or overload current and an electric arc is generated. Sulfur hexafluoride gas acts as an arc-extinguishing medium to adsorb free electrons in the electric arc and extinguish the electric arc.

[0035] like Figure 2and Figure 3 As shown, in order to facilitate the filling of sulfur hexafluoride gas into the sealed cavity, one of the sealing gaskets 4 is provided with a gas filling valve 6. After the sulfur hexafluoride gas is filled into the sealed cavity through the gas filling valve 6, the cavity is sealed by spot welding. Before filling the sealed cavity with sulfur hexafluoride gas through the gas filling valve 6, the air in the sealed cavity needs to be emptied by a vacuum pump through the gas filling valve 6, and then the sulfur hexafluoride gas is filled into the sealed cavity through the gas filling valve 6.

[0036] The pressure of sulfur hexafluoride gas in the sealed cavity can be adjusted according to the usage requirements. In this embodiment, the pressure of sulfur hexafluoride gas in the sealed cavity is 0.2 MPa.

[0037] In other embodiments, to facilitate the filling of the sealed cavity with sulfur hexafluoride gas, such as Figure 5 As shown, one of the sealing gaskets 4 is provided with two inflation valves 6 of different lengths; when sulfur hexafluoride gas is filled into the sealing cavity through the longer inflation valve 6, the air in the sealing cavity is discharged through the shorter inflation valve 6; after the sulfur hexafluoride gas fills the sealing cavity, both inflation valves 6 are sealed by spot welding.

[0038] By setting two inflation valves 6 with different lengths, one long and one short, it is easy to identify the inflation valve 6 used for inflation and the inflation valve 6 used for venting air. In actual operation, either inflation valve 6 can be used for inflation.

[0039] Since sulfur hexafluoride gas is denser than air, when sulfur hexafluoride gas is introduced into the sealed cavity through the longer filling valve 6, the air in the sealed cavity can be discharged through the shorter filling valve 6, which helps to improve the efficiency of introducing sulfur hexafluoride gas into the sealed cavity and further improves the assembly efficiency of the fuse.

[0040] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any changes or substitutions within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A sulfur hexafluoride fuse comprising an end-face metallized fuse tube (1) and a fuse body (3) located inside the end-face metallized fuse tube (1), characterized in that: two ends of the fuse body (3) are connected to two end faces (2) of the end-face metallized fuse tube (1) respectively; each of the two end faces (2) of the end-face metallized fuse tube (1) is provided with a sealing gasket (4), and a sealed cavity is formed between the two sealing gaskets (4) and the end-face metallized fuse tube (1); the sealed cavity is filled with sulfur hexafluoride gas as arc extinguishing medium; and each end of the end-face metallized fuse tube (1) is provided with a connecting terminal (5) which is electrically connected to the sealing gasket (4). The fuse body (3) is in a Z shape, and two ends of the fuse body (3) are connected to two end faces (2) of the end-face metallized fuse tube (1) respectively. The fuse body (3) is provided with a plurality of uniformly distributed narrow sections (7); when a short-circuit current or an overload current passes through the fuse body (3), the narrow sections (7) of the fuse body (3) are fused and an arc is generated by the thermal effect of the short-circuit current or the overload current, and the arc is extinguished by the sulfur hexafluoride gas as arc extinguishing medium absorbing free electrons in the arc. One of the sealing gaskets (4) is provided with a gas filling valve (6), and after the sulfur hexafluoride gas is filled into the sealed cavity through the gas filling valve (6), the two gas filling valves (6) are sealed and blocked by spot welding.

2. The sulfur hexafluoride circuit breaker of claim 1, wherein: One of the sealing gaskets (4) is provided with two gas filling valves (6) with different lengths.

3. The sulfur hexafluoride circuit breaker according to any of claims 1 or 2, characterized in that: When the sulfur hexafluoride gas is filled into the sealed cavity through the longer gas filling valve (6), the air in the sealed cavity is discharged through the shorter gas filling valve (6); and after the sulfur hexafluoride gas fills the sealed cavity, the two gas filling valves (6) are sealed and blocked by spot welding.

4. The sulfur hexafluoride circuit breaker of claim 1, wherein: The sealing gasket (4) and the end face (2) of the end-face metallized fuse tube (1) are fixed by welding.

5. The sulfur hexafluoride circuit breaker of claim 1, wherein: The pressure of the sulfur hexafluoride gas in the sealed cavity is 0.1-10 MPa. ​ 6. The sulfur hexafluoride circuit breaker of claim 1, wherein: ​ 7. The SF6 fuse according to any of claims 1 or 4 or 5, characterized in that: ​

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