A cable joint explosion-proof box pressure relief and flame-out structure

Abstract

The application relates to a cable joint explosion-proof box pressure relief and flame elimination structure, which comprises an explosion-proof shell with an inner cavity formed inside, and a plurality of pressure relief and flame elimination components communicated and arranged on the peripheral side of the explosion-proof shell, the end portions of two end cables extending into the explosion-proof shell for connection; the pressure relief and flame elimination component comprises a connecting shell communicated with the explosion-proof shell and a fire filter bag communicated and arranged at the tail end of the connecting shell, and an inlet section, a filter section, a heat absorption section, a flame elimination section and a check section are sequentially arranged in the connecting shell from the top end to the tail end. In the application, the filter section, the heat absorption section, the flame elimination section and the check section are sequentially arranged on the pressure relief path, and the flexible fire filter bag at the tail end is combined to form a complete energy consumption chain. The high temperature, high pressure, combustible gas and metal droplet generated by the short circuit arc can be processed step by step, the temperature of the exhaust gas is reduced, the flame is eliminated, the surrounding cable is prevented from being ignited, and secondary fire is prevented from being caused.

Description

Technical Field

[0001] This invention relates to the field of cable connection, and in particular to a pressure relief and flame suppression structure for an explosion-proof cable joint box. Background Technology

[0002] Cable joints are among the weakest links in power transmission systems. After long-term high-load operation, the insulation performance of cable joints is prone to decline due to moisture, dielectric aging, or mechanical damage, leading to partial discharge, phase-to-phase, or phase-to-ground short-circuit faults. During a short-circuit fault, the current surges to tens of times the normal value, instantly generating a high-temperature arc with a temperature exceeding 3000℃, sufficient to melt the metal conductor and cause thermal decomposition of the insulation material, releasing a large amount of flammable gas.

[0003] To reduce the safety risks posed by cable joint failures, explosion-proof protection devices are commonly installed at cable joints in power engineering projects. The deflagration following a short circuit at a cable joint is caused by the combined effects of high temperature and high pressure; relying solely on the strength of the cable casing is insufficient to fundamentally prevent the release of deflagration energy and its ignition of surrounding materials. Summary of the Invention

[0004] In view of this, the present invention aims to provide a pressure relief and flame suppression structure for an explosion-proof cable joint box to solve the problems in the prior art.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows: This invention discloses a pressure relief and flame suppression structure for an explosion-proof cable connector box, comprising an explosion-proof shell with an internal cavity, and multiple pressure relief and flame suppression components connected around the explosion-proof shell, wherein the ends of the cables at both ends extend into the explosion-proof shell for connection. The pressure relief and flame extinguishing assembly includes a connecting shell that communicates with the explosion-proof shell and a fire filter bag that is connected to the tail end of the connecting shell. The connecting shell is provided with an inlet section, a filter section, a heat absorption section, a flame extinguishing section and a backflow prevention section from the top to the tail end. The filtration section is provided with a filtration layer, the heat absorption section is provided with a heat absorption layer, the flame extinguishing section is provided with a flame arrestor plate, and the backflow prevention section is provided with a backflow prevention component.

[0006] Furthermore, the backstop assembly includes a retaining ring, a baffle plate, a guide rod, a spring, and a connecting rod; The fixing ring is fixedly disposed on the inner side wall of the non-return section, and the outer circumference of the fixing ring conforms to the inner contour of the non-return section. The end of the guide rod is fixedly connected to the fixing ring through a connecting rod. The baffle is slidably connected to the guide rod. The spring is sleeved on the guide rod. The other end of the guide rod is fixedly provided with a base plate. One end of the spring is fixedly connected to the baffle and the other end is fixedly connected to the base plate.

[0007] Furthermore, an installation frame is fixedly provided within the inlet section, and a destructible rupture disc is fixedly provided within the installation frame.

[0008] Furthermore, the cross-section of the flame arrestor is wavy and has multiple segments spaced apart.

[0009] Furthermore, the filter bag is fixedly connected to and communicates with the tail end of the connecting shell via a flange.

[0010] Furthermore, the fire filter bag is folded when not in use.

[0011] Compared with the prior art, the present invention has the following advantages: In this invention, a complete energy absorption chain is formed by sequentially setting a filtration section, a heat absorption section, a flame extinguishing section, and a backflow prevention section along the pressure relief path, combined with a flexible fire filter bag at the end. This chain can process the high temperature, high pressure, combustible gas, and molten metal droplets generated by the short-circuit arc in stages, reducing the temperature of the exhaust gas and eliminating the flame, thus preventing the ignition of surrounding cables or secondary fires. Attached Figure Description

[0012] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the pressure relief and flame extinguishing assembly structure of the present invention; Figure 3 This is a schematic diagram of the backstop assembly structure of the present invention; Figure 4 This is a schematic diagram of the fixing ring structure of the present invention.

[0013] Explanation of reference numerals in the attached figures: 1. Explosion-proof housing; 2. Connecting housing; 201. Inlet section; 202. Filter section; 203. Heat absorption section; 204. Flame extinguishing section; 205. Backflow prevention section; 3. Rupture disc; 301. Mounting frame; 4. Filter layer; 5. Heat absorption layer; 6. Flame arrestor plate; 7. Backflow prevention assembly; 701. Fixing ring; 702. Shielding plate; 703. Guide rod; 704. Spring; 705. Base plate; 706. Connecting rod; 8. Filter bag. Detailed Implementation

[0014] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0015] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "back," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0016] Furthermore, in the description of this invention, unless otherwise explicitly defined, the terms "installation," "connection," "linking," and "connector" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention in light of the specific circumstances.

[0017] The following will refer to the appendix. Figures 1 to 4 The present invention will be described in detail with reference to the embodiments.

[0018] Overall, this invention discloses a pressure relief and flame extinguishing structure for an explosion-proof cable connector box, including an explosion-proof shell 1 with an internal cavity, and multiple pressure relief and flame extinguishing components connected around the explosion-proof shell 1. The ends of the cables at both ends extend into the explosion-proof shell 1 for connection, and the fire filter bag 8 is in a folded state when not in operation. like Figure 2 As shown, the pressure relief and flame suppression assembly includes a connecting shell 2 connected to the explosion-proof shell 1, and a fire filter bag 8 connected to the tail end of the connecting shell 2. The connecting shell 2 is provided with an inlet section 201, a filter section 202, a heat absorption section 203, a flame suppression section 204, and a backflow prevention section 205 in sequence from the top to the tail end. The filter section 202 is provided with a filter layer 4, the heat absorption section 203 is provided with a heat absorption layer 5, the flame suppression section 204 is provided with a flame arrestor 6, and the backflow prevention section 205 is provided with a backflow prevention assembly 7.

[0019] In this embodiment, a complete energy absorption chain is formed by sequentially setting a filter section 202, a heat absorption section 203, a flame extinguishing section 204, and a check valve section 205 along the pressure relief path, combined with a flexible fire filter bag 8 at the end. This chain can process the high temperature, high pressure, combustible gas, and molten metal droplets generated by the short-circuit arc in stages, reducing the temperature of the exhaust gas and eliminating the flame, thus preventing the ignition of surrounding cables or secondary fires.

[0020] The filter layer 4 (such as high-temperature resistant ceramic fiber felt) in the filter section 202 can effectively intercept micron-sized molten copper droplets, aluminum droplets and other metal particles, blocking the source of fire from being ejected with the airflow, thus solving the problem of fire emission during the depressurization of traditional explosion-proof boxes.

[0021] The heat-absorbing layer 5 in the heat-absorbing section 203 uses a phase change material (such as magnesium chloride hexahydrate), which absorbs a large amount of heat and releases crystalline water vapor at high temperatures, which can reduce the airflow temperature and dilute the concentration of combustible gas. The flame arrestor plate 6 in the flame-extinguishing section 204 (such as a multi-layer metal flame arrestor mesh, or an inorganic phase change composite material or a metal foam composite phase change material) can further block combustion and forcibly extinguish residual flames, achieving dual chemical and physical flame extinguishing.

[0022] The backstop component 7 inside the backstop section 205 automatically closes after the pressure is released. When backfire or backflow occurs externally, it can quickly block the flame and high-temperature gas from entering the explosion-proof housing 1 in reverse, preventing repeated damage to the cable joint or causing another explosion.

[0023] It should be further explained that the filter section 202 is filled with a filter layer 4. The filter layer 4 is made of ceramic fiber felt with a temperature resistance of over 1400℃, a thickness of 20~30mm, and a porosity of 85%~90%. The filter layer 4 can intercept micron-sized molten copper droplets, aluminum droplets, and carbide particles carried in the airflow, preventing metal droplets from entering the downstream and causing secondary ignition.

[0024] The heat-absorbing section 203 is filled with a heat-absorbing layer 5. The heat-absorbing layer 5 is made of magnesium chloride hexahydrate phase change material and can be in granular or porous block form. This material begins to dehydrate at approximately 117°C, absorbing a large amount of heat and releasing water vapor. The water vapor lowers the airflow temperature and dilutes the concentration of combustible gases while inhibiting deflagration. The length of the heat-absorbing section 203 is designed to be 80-120 mm to ensure sufficient heat exchange time for the airflow.

[0025] The flame arrestor plate 6 is made of multiple layers of stainless steel corrugated strips, forming a tortuous flue gas channel.

[0026] The fire filter bag 8 is made of flexible multi-layer high-temperature resistant material (such as aramid fiber or ceramic fiber fabric). It is folded and stored normally, and it quickly inflates and forms a long channel when the pressure is released, which prolongs the flow path of high-temperature gas, further blocking the flame, cooling, and settling particulate matter, ensuring that the final emitted gas is safe and flameless.

[0027] In this embodiment, when a short circuit fault occurs to ground or between phases at the cable joint, a high-temperature arc is instantly generated, causing the insulation material to thermally decompose and release a large amount of combustible gas (mainly composed of methane, ethane, hydrogen, etc.), and the pressure and temperature in the inner cavity rise sharply. When the pressure reaches the pressure relief threshold (e.g., 0.5~1.0 MPa), the high-temperature and high-pressure airflow enters the various functional sections of the pressure relief and flame extinguishing assembly through the pressure relief port in sequence: the airflow first enters the filter section 202, where the ceramic fiber felt filter layer 4 intercepts molten metal droplets, preventing them from being ejected with the airflow and causing an external fire. Next, it enters the heat absorption section 203, where the magnesium chloride hexahydrate phase change material in the heat absorption layer 5 rapidly absorbs heat and releases water vapor, significantly reducing the airflow temperature and diluting the concentration of combustible gas. Then, it enters the flame extinguishing section 204, where the flame arrestor plate 6 bends the metal mesh channel to block the combustion chain reaction, forcibly extinguishing the residual flame and completely extinguishing any remaining flames that may exist in the airflow. After flame extinguishing, the airflow pushes the backstop assembly 7 to open, rushing out from the tail end of the connecting shell 2 and entering the flexible fire filter bag 8. The fire filter bag 8 quickly unfolds, and the airflow continues to flow, cool, and settle particulate matter in the long channel.

[0028] like Figure 3 and Figure 4 As shown, the aforementioned backstop assembly 7 includes a fixing ring 701, a baffle plate 702, a guide rod 703, a spring 704, and a connecting rod 706. The fixing ring 701 is fixedly disposed on the inner side wall of the backstop section 205, and the outer circumference of the fixing ring 701 conforms to the inner contour of the backstop section 205. The end of the guide rod 703 is fixedly connected to the fixing ring 701 through the connecting rod 706. The baffle plate 702 is slidably connected to the guide rod 703. The spring 704 is fitted on the guide rod 703. The other end of the guide rod 703 is fixedly provided with a base plate 705. One end of the spring 704 is fixedly connected to the baffle plate 702, and the other end is fixedly connected to the base plate 705.

[0029] Under normal operating conditions, the shielding plate 702, under the preload of the spring 704, is tightly pressed against the fixing plate, closing the pressure relief channel and preventing external moisture or debris from entering the explosion-proof housing 1. When a short circuit occurs at the cable joint, the internal pressure of the explosion-proof housing 1 rises sharply. The high-temperature, high-pressure airflow passes through the filter section 202, the heat absorption section 203, and the flame extinguishing section 204 before entering the check section 205. The airflow overcomes the elastic force of the spring 704, pushing the shielding plate 702 to slide along the guide rod 703 towards the bottom plate 705, thereby opening the vent on the fixing plate and establishing a pressure relief channel. After pressure relief is completed, when the internal pressure drops below the elastic force of the spring 704, the spring 704 pushes the shielding plate 702 to slide in the opposite direction along the guide rod 703, pressing it back against the fixing plate and reliably closing the pressure relief channel. Even if backfire or backdraft occurs externally, the shielding plate 702 will fit more tightly against the fixing plate due to the combined action of reverse air pressure and spring 704, effectively blocking the flame and high-temperature gas from entering the explosion-proof housing 1 in reverse.

[0030] Spring 704 is made of high-temperature resistant elastic alloy material to ensure that it can maintain sufficient elastic restoring force after the high-temperature airflow passes through the stop section 205.

[0031] Based on the above settings, such as Figure 2 As shown, the flame arrestor 6 has a wavy cross-section and multiple pieces are spaced apart. This configuration allows the wavy cross-section to significantly increase the contact area between the airflow and the flame arrestor 6, enabling the high-temperature gas to dissipate heat fully as it passes through the tortuous channel.

[0032] As a preferred structure in this embodiment, an installation frame 301 is fixedly provided inside the inlet section 201, and a destructible rupture disc 3 is fixedly provided inside the installation frame 301.

[0033] To facilitate the installation of the fire filter bag 8, in this embodiment, the fire filter bag 8 is fixedly connected and communicates with the tail end of the connecting shell 2 via a flange.

[0034] It should be noted that the rupture disc 3 is a thin metal film (such as stainless steel or nickel-based alloy). Under normal operating conditions, the rupture disc 3 remains intact, isolating the inner cavity of the explosion-proof housing 1 from the various sections of the pressure relief and flame extinguishing assembly (filter section 202, heat absorption section 203, flame extinguishing section 204, and backflow prevention section 205). When a short circuit occurs at the cable joint, the pressure inside the explosion-proof housing 1 rises sharply and reaches the set burst pressure of the rupture disc 3. The rupture disc 3 then ruptures instantly, opening the pressure relief channel, allowing the high-temperature, high-pressure airflow to quickly enter the filter section 202 and subsequent functional sections.

[0035] In this embodiment, the filter bag 8 is fixedly connected and communicates with the tail end of the connecting shell 2 via a flange. Specifically, a flange is fixedly installed at the outlet of the tail end of the connecting shell 2, and a corresponding flange is also installed at the inlet end of the flexible filter bag 8. The two flanges are fastened together with bolts and nuts, and a high-temperature resistant sealing gasket (such as an expanded graphite composite gasket or a ceramic fiber gasket) is placed on the sealing surface of the flange to ensure a reliable airtight connection. The flange connection method is convenient to install, has good sealing performance, and facilitates on-site replacement of the filter bag 8.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A pressure relief and flame suppression structure for an explosion-proof cable joint box, characterized in that: It includes an explosion-proof housing (1) with an internal cavity, and multiple pressure relief and flame extinguishing components connected to the periphery of the explosion-proof housing (1), with the ends of the cables at both ends extending into the explosion-proof housing (1) for connection; The pressure relief and flame extinguishing assembly includes a connecting shell (2) that communicates with the explosion-proof shell (1) and a fire filter bag (8) that is connected to the tail end of the connecting shell (2). The connecting shell (2) is provided with an inlet section (201), a filter section (202), a heat absorption section (203), a flame extinguishing section (204), and a backflow prevention section (205) in sequence from the top to the tail end. The filter section (202) is provided with a filter layer (4), the heat absorption section (203) is provided with a heat absorption layer (5), the flame extinguishing section (204) is provided with a flame arrestor plate (6), and the backstop section (205) is provided with a backstop assembly (7).

2. The pressure relief and flame suppression structure for an explosion-proof cable joint box according to claim 1, characterized in that: The backstop assembly (7) includes a retaining ring (701), a baffle plate (702), a guide rod (703), a spring (704), and a connecting rod (706). The fixing ring (701) is fixedly disposed on the inner side wall of the non-return section (205). The outer circumference of the fixing ring (701) conforms to the inner contour of the non-return section (205). The end of the guide rod (703) is fixedly connected to the fixing ring (701) through the connecting rod (706). The shielding plate (702) is slidably connected to the guide rod (703). The spring (704) is sleeved on the guide rod (703). The other end of the guide rod (703) is fixedly provided with a base plate (705). One end of the spring (704) is fixedly connected to the shielding plate (702), and the other end is fixedly connected to the base plate (705).

3. A pressure relief and flame extinguishing structure for an explosion-proof cable joint box according to claim 1 or 2, characterized in that: An installation frame (301) is fixedly provided inside the inlet section (201), and a rupture disc (3) that can be destroyed is fixedly provided inside the installation frame (301).

4. The pressure relief and flame suppression structure for an explosion-proof cable joint box according to claim 1, characterized in that: The cross-section of the fire-retardant sheet (6) is wavy and has multiple pieces spaced apart.

5. The pressure relief and flame suppression structure for an explosion-proof cable joint box according to claim 1, characterized in that: The fire filter bag (8) is fixedly connected to the tail end of the connecting shell (2) via a flange and is in communication with it.

6. A pressure relief and flame extinguishing structure for an explosion-proof cable joint box according to any one of claims 1 or 5, characterized in that: The fire filter bag (8) is folded when not in use.

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