A pyrotechnic fuse

Abstract

The utility model relates to fuse technology field, concretely relates to a pyrotechnic fuse; the inside of casing is divided into accommodation cavity and arc extinguishing cavity through conductor; the sliding installation of accommodation cavity is provided with the pressing plate, and the bottom of pressing plate is filled with arc extinguishing medium between the top of conductor; arc extinguishing cavity is equipped with elastic damping part, and the both ends of elastic damping part are respectively with the bottom of conductor, the inner bottom surface of casing abut; when the igniter is triggered, the high pressure gas is produced in the top space of pressing plate, and the high pressure gas pushes the pressing plate and arc extinguishing medium and moves down and cuts off the conductor, and the broken part of arc extinguishing medium and conductor is opposite sliding and stops between the broken part of conductor. The utility model combines the pressing plate and arc extinguishing medium, not only replaces the piston made of engineering plastics in the mainstream arc extinguishing route, but also can replace the steel wire mesh arc extinguishing and parallel fuse arc extinguishing mode, avoids the risk because of piston failure, enhances the breaking capacity of pyrotechnic fuse, reduces the overall volume of fuse simultaneously.

Description

Technical Field

[0001] This utility model relates to the field of fuse technology, specifically to a pyrotechnic fuse. Background Technology

[0002] Most existing pyrotechnic fuses mainly consist of a gas generating device (including an igniter), a piston, a copper plate, and an arc-extinguishing chamber. When a fault current occurs or a signal is received, the igniter detonates, generating high-pressure gas that drives the piston to break the copper plate, thus rapidly disconnecting the circuit. Since cutting the copper plate is similar to a power outage, an electric arc will be generated at the break point. Therefore, the entire device needs to extinguish the arc within a very short time after the copper plate is broken. Currently, wire mesh arc extinguishing schemes and parallel fuse arc extinguishing schemes are the mainstream approaches for arc extinguishing in pyrotechnic fuses.

[0003] In current mainstream solutions, pistons are all made entirely of special engineering plastics. However, plastic pistons have many drawbacks, such as poor high-temperature resistance, poor thermal conductivity, and low hardness. During the entire operation of a pyrotechnic fuse, these shortcomings can easily lead to a series of problems, such as piston deformation at high temperatures, arc burns, poor heat conduction, and low cutting speed. Specifically, the piston tip is burned by the arc during operation, causing the cutting edge to soften and preventing the copper plate from being effectively cut, increasing the risk of device failure. Furthermore, plastic pistons have poor resistance to corrosive substances such as gunpowder gases and metal vapors, making them prone to failure in harsh environments.

[0004] The core of the wire mesh arc extinguishing scheme mainly consists of two aspects: first, filling the arc extinguishing chamber with wire mesh, utilizing the high thermal conductivity and large surface area of ​​the metal to dissipate arc energy and extinguish the arc; second, relying on its special spatial mesh structure, dividing the arc into small, short arcs, increasing the voltage drop to extinguish the arc. This scheme has obvious advantages, low initial cost, and ease of manufacturing, but it also has some drawbacks: First, the heat capacity of the wire mesh is limited; for example, in short-time high-current systems above 1000V, a sufficiently large filling volume is required, which increases the size of the equipment; second, the high temperature of the arc can easily melt the wire mesh, forming metal vapor, which can easily trigger secondary arc reignition; finally, the fixed position of the wire mesh and changes in the wire diameter can also have a certain negative impact on arc extinguishing.

[0005] The parallel fuse arc extinguishing scheme includes a gas generator (igniter), piston, copper plate, and fuse connected in parallel. During normal operation, current flows through the main copper busbar. In case of a fault, the high-pressure gas generated by the igniter pushes the piston to break the copper plate. Current then flows to the fuse, which melts and extinguishes the arc in the quartz sand chamber, ultimately disconnecting the system circuit. To achieve "zero-current" disconnection, a fuse cutter is typically added. While breaking the copper plate, the piston continues to move downwards, pushing the fuse cutter to cut the fuse wire, thus disconnecting the entire circuit. This scheme addresses high breaking requirements to some extent, but it also has drawbacks: First, the timing of actions is difficult to coordinate; mechanical switching and fuse melting both require time, resulting in a long total delay, while DC systems require the fastest possible breaking speed. Second, the success rate of current transfer is affected by circuit impedance matching; when the impedance is high, the risk of the main copper busbar burning out and exploding increases. Third, adding a fuse adds an extra system to the product structure, complicating the manufacturing process and increasing costs.

[0006] In summary, the mainstream approaches to arc extinguishing using existing pyrotechnic fuses all have certain problems: plastic pistons have poor temperature resistance; wire mesh arc extinguishing requires a large volume and has a high probability of arc reignition; and parallel fuse arc extinguishing has problems such as timing coordination issues. Utility Model Content

[0007] The purpose of this invention is to solve the technical problems of existing pyrotechnic fuse arc extinguishing methods, such as poor temperature resistance of plastic pistons, large volume requirements for steel wire mesh arc extinguishing, high probability of arc reignition, and the need for coordinated action timing in parallel fuse arc extinguishing. Therefore, this invention provides a pyrotechnic fuse.

[0008] To solve the above-mentioned technical problems, the technical solution provided by this utility model is as follows:

[0009] A pyrotechnic fuse includes a housing, an igniter at the top of the housing, and a conductor in the middle of the housing, with both ends of the conductor penetrating the housing and extending to the outside of the housing; the interior of the housing is divided into a receiving cavity and an arc-extinguishing cavity by the conductor.

[0010] A pressure plate is slidably installed inside the accommodating cavity, and an arc-extinguishing medium is filled between the bottom of the pressure plate and the top of the conductor.

[0011] The arc-extinguishing cavity is equipped with an elastic damping element, and the two ends of the elastic damping element abut against the bottom of the conductor and the inner bottom surface of the shell, respectively.

[0012] When the igniter is triggered, it generates high-pressure gas in the space above the pressure plate. The high-pressure gas pushes the pressure plate and the arc-extinguishing medium downward to cut the conductor. The arc-extinguishing medium slides relative to the broken ends of the conductor and stops between the broken ends.

[0013] Furthermore, the shape of the arc-extinguishing medium is fixed by a spatial structure formed by a pressure plate, the inner wall of the shell, and the conductor, which is a medium without a fixed shape.

[0014] Furthermore, the arc-extinguishing medium is a liquid medium or a solid medium with weak intermolecular bonding that cannot maintain a specific morphology.

[0015] Furthermore, the arc-extinguishing medium is quartz sand.

[0016] Furthermore, the elastic damping element is a support spring used to stabilize the falling stability of the severed conductor and to maintain the compactness of the arc-extinguishing medium.

[0017] Furthermore, cutting auxiliary grooves are provided on both sides of the bottom of the conductor near the sidewalls of the arc-extinguishing cavity;

[0018] After the pressure plate and the arc-extinguishing medium move downwards and cut the conductor, the conductor's cutting auxiliary groove forms the fracture.

[0019] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0020] The pyrotechnic fuse provided by this utility model, by combining a pressure plate with an arc-extinguishing medium, not only replaces the piston made of engineering plastics in existing mainstream arc-extinguishing circuits, but also replaces wire mesh arc extinguishing and parallel fuse arc extinguishing methods. Compared with existing mainstream arc-extinguishing circuits, the combination of the arc-extinguishing medium and the pressure plate has stronger high-temperature resistance and thermal conductivity, avoiding the risks caused by piston failure in existing technologies, enhancing the breaking capacity of the pyrotechnic fuse, and reducing the overall size of the fuse. Furthermore, an elastic damping element is installed at the bottom of the conductor, which not only improves the compactness of the arc-extinguishing medium, but also retains the conductor after it is broken, allowing the arc-extinguishing medium to slide within the shell and remain between the broken ends of the conductor. 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 a schematic diagram of the structure after the conductor is cut in an embodiment of this utility model.

[0023] Explanation of reference numerals in the attached drawings: 1-shell, 2-igniter, 3-conductor, 4-accommodating cavity, 5-arc extinguishing cavity, 6-pressure plate, 7-arc extinguishing medium, 8-elastic damping element. Detailed Implementation

[0024] 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.

[0025] like Figure 1 As shown, a pyrotechnic fuse includes a housing 1, an igniter 2 at the top of the housing 1, a conductor 3 in the middle of the housing 1, and two ends of the conductor 3 passing through the housing 1 and extending to the outside of the housing 1; the interior of the housing 1 is divided into a receiving cavity 4 and an arc-extinguishing cavity 5 by the conductor 3.

[0026] A pressure plate 6 is slidably installed inside the cavity 4, and an arc-extinguishing medium 7 is filled between the bottom of the pressure plate 6 and the top of the conductor 3.

[0027] In this embodiment, the arc-extinguishing medium 7 is quartz sand with weak intermolecular bonding and unable to maintain a specific shape; the shape of the arc-extinguishing medium 7 is fixed by the spatial structure formed by the pressure plate 6, the inner wall of the shell 1 and the conductor 3;

[0028] The arc-extinguishing chamber 5 is provided with an elastic damping element 8. The elastic damping element 8 is a support spring used to stabilize the falling stability of the cut conductor 3 and to maintain the compactness of the arc-extinguishing medium 7. The two ends of the elastic damping element 8 abut against the bottom of the conductor 3 and the inner bottom surface of the shell 1, respectively.

[0029] like Figure 2 As shown, when the igniter 2 is triggered, the igniter 2 generates high-pressure gas in the space above the pressure plate 6. The high-pressure gas pushes the pressure plate 6 and the arc-extinguishing medium 7 to move downwards and cut the conductor 3. The arc-extinguishing medium 7 slides relative to the broken end of the conductor 3 and stops between the broken ends of the conductor 3.

[0030] In this embodiment, the pressure plate 6 and the arc-extinguishing medium 7 are combined to form a moving part. When the pressure plate 6 and the arc-extinguishing medium 7 move downward to cut the conductor 3, the arc-extinguishing medium 7 immediately participates in arc extinguishing. The arc-extinguishing medium 7 used in this embodiment is quartz sand, which has a high energy absorption density. Its arc energy absorption density is more than 1.5 times higher than that of the wire mesh scheme, so it can be applied to subsequent high-voltage and high-current breaking scenarios.

[0031] Meanwhile, the combination of the arc-extinguishing medium 7 and the pressure plate 6 effectively prevents the conductor 3 from breaking due to the plastic piston softening when exposed to an electric arc. Furthermore, this method can eliminate the need for the piston and arc-extinguishing device, reducing the overall device size by 25-40%; it can also eliminate the need for the piston and wire mesh or parallel fuse arc-extinguishing structure. Since quartz sand is less expensive than plastic and wire mesh or fuse structures, the overall material and assembly costs can be reduced by 15-30%.

[0032] In addition, the insulation recovery rate of quartz sand is higher; for example, in a 1500V system, the insulation strength can be restored within 0.5ms.

[0033] In other embodiments of this utility model, cutting auxiliary grooves are provided on both sides of the bottom of the conductor 3 near the side wall of the arc extinguishing cavity 5; when the pressure plate 6 and the arc extinguishing medium 7 move downward to cut the conductor 3, the cutting auxiliary grooves of the conductor 3 form a break.

[0034] 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 pyrotechnic fuse, comprising a housing (1), an igniter (2) at the top of the housing (1), and a conductor (3) in the middle of the housing (1), the two ends of the conductor (3) passing through the housing (1) and extending to the outside of the housing (1); the interior of the housing (1) is divided into a receiving cavity (4) and an arc-extinguishing cavity (5) by the conductor (3); characterized in that: A pressure plate (6) is slidably installed in the cavity (4), and an arc-extinguishing medium (7) is filled between the bottom of the pressure plate (6) and the top of the conductor (3); The arc-extinguishing cavity (5) is provided with an elastic damping element (8), and the two ends of the elastic damping element (8) abut against the bottom of the conductor (3) and the inner bottom surface of the shell (1), respectively. When the igniter (2) is triggered, the igniter (2) generates high-pressure gas in the space at the top of the pressure plate (6). The high-pressure gas pushes the pressure plate (6) and the arc-extinguishing medium (7) downward to cut the conductor (3). The arc-extinguishing medium (7) and the broken end of the conductor (3) slide relative to each other and stop between the broken ends of the conductor (3).

2. The pyrotechnic fuse according to claim 1, characterized in that: The shape of the arc-extinguishing medium (7) is fixed by a spatial structure formed by a medium without a fixed shape through a pressure plate (6), the inner wall of the shell (1) and the conductor (3).

3. The pyrotechnic fuse according to claim 1, characterized in that: The arc-extinguishing medium (7) is a liquid medium or a solid medium with weak intermolecular bonding that cannot maintain a specific form.

4. The pyrotechnic fuse according to claim 1, characterized in that: The arc-extinguishing medium (7) is quartz sand.

5. The pyrotechnic fuse according to claim 1, characterized in that: The elastic damping element (8) is a support spring used to stabilize the falling stability of the severed conductor (3) and to maintain the compactness of the arc-extinguishing medium (7).

6. The pyrotechnic fuse according to claim 1, characterized in that: The bottom sides of the conductor (3) are provided with cutting auxiliary grooves near the side walls of the arc extinguishing cavity (5); When the pressure plate (6) and the arc-extinguishing medium (7) move downwards to cut the conductor (3), the cutting auxiliary groove of the conductor (3) forms the fracture.

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