Positive pressure type electrical cabinet explosion-proof device

Abstract

This utility model relates to the field of electrical cabinet technology and discloses a positive pressure type explosion-proof device for electrical cabinets. It includes an electrical cabinet and a cabinet door hinged to the front of the electrical cabinet. An inner cabinet body is connected internally to the electrical cabinet, and an inner door is hinged to the front of the inner cabinet body. A sealing strip is installed on the inner wall of the inner door, and an explosion-proof sealing mechanism is provided on the inner wall of the inner cabinet body. The sealing mechanism includes a limiting frame, an elastic airbag, an air supply pipe, and a metal spring. This positive pressure type explosion-proof device for electrical cabinets, by using an elastic airbag that remains inflated, combined with the arc-shaped metal spring, continuously provides stable adhesion pressure to the sealing strip. Even if the sealing strip shows slight aging due to long-term use, the elastic recovery ability of the metal spring and the supporting effect of the elastic airbag can compensate for the decrease in elasticity of the sealing strip, maintaining a tight fit between the sealing strip and the contact surface, and ensuring the sealing performance of the electrical cabinet.

Description

Technical Field

[0001] This utility model belongs to the field of electrical cabinet technology, specifically, it relates to a positive pressure type explosion-proof device for electrical cabinets. Background Technology

[0002] In flammable and explosive hazardous locations such as petroleum, chemical, and coal mines, positive pressure electrical cabinets are key equipment to ensure the safe operation of electrical equipment. Their core principle is to maintain the air pressure inside the cabinet higher than that of the external environment, thereby preventing flammable and explosive gases from entering the cabinet and thus avoiding explosions caused by sparks generated by the operation of electrical components.

[0003] A common problem with existing positive-pressure electrical cabinets is the degradation of their sealing performance over long-term use. Traditional positive-pressure electrical cabinets rely heavily on a single rubber sealing strip to seal the cabinet body and door. With prolonged use, this sealing strip gradually ages, deforms, and loses elasticity due to environmental temperature fluctuations (such as heat generated by electrical components and changes in ambient temperature), mechanical wear from frequent opening and closing of the cabinet door, and corrosion from oil and corrosive gases in hazardous locations. This leads to a continuous increase in the gap between the sealing strip and the cabinet body and door, significantly deteriorating the cabinet's sealing performance and making it impossible to maintain a stable positive pressure environment. If flammable or explosive gases from the outside enter the cabinet through the sealing gaps and come into contact with sparks generated by the electrical components, an explosion can easily occur, seriously threatening the safety of on-site equipment and personnel. This also shortens the overall lifespan of the electrical cabinet and increases the company's maintenance costs. Utility Model Content

[0004] The purpose of this invention is to provide a positive pressure type explosion-proof device for electrical cabinets to solve the problems mentioned in the background art.

[0005] An explosion-proof device for a positive pressure electrical cabinet includes an electrical cabinet and a cabinet door hinged to the front of the electrical cabinet. An inner cabinet is connected to the interior of the electrical cabinet. An inner door is hinged to the front of the inner cabinet. A sealing strip is installed on the inner wall of the inner door. An explosion-proof sealing mechanism is provided on the inner wall of the inner cabinet.

[0006] The sealing mechanism includes a limiting frame, an elastic airbag, an air supply pipe, and a metal spring. The limiting frame is fixedly connected to the inner wall of the inner cabinet, the elastic airbag is fixedly connected to the inner wall of the limiting frame, the air supply pipe is fixedly connected to the back of the elastic airbag, and the metal spring is fixedly connected to the side of the elastic airbag away from the limiting frame.

[0007] In a preferred embodiment of this utility model, the metal spring is made of spring steel, has an arc-shaped structure, and has elastic restoring capability. The elastic airbag is filled with nitrogen gas, and the micro protrusions on the outer wall of the metal spring are tightly fitted with the sealing strip.

[0008] In a preferred embodiment of this utility model, the inner wall of the inner cabinet is connected to a memory metal frame, which is located between the elastic airbag and the sealing strip. The phase change temperature of the memory metal frame is set to 55°C. When the internal temperature of the cabinet rises to 55°C due to the heating of electrical components, the memory metal frame automatically contracts.

[0009] In a preferred embodiment of this utility model, a load-bearing frame is fixedly connected to the left and right sides of the inner wall of the inner cabinet. A partition and a connecting frame are fixedly connected to the inner wall of the load-bearing frame. An installation plate is fixedly connected to the inner wall of the connecting frame. Electrical components are installed on the back of the installation plate.

[0010] In a preferred embodiment of this utility model, a glass door is installed at the center of the front of the cabinet door, and the glass door is made of tempered explosion-proof glass.

[0011] In a preferred embodiment of this utility model, a lower housing is fixedly installed at the bottom of the electrical cabinet. The lower housing is connected to the bottom of the electrical cabinet through a partition plate. A through hole is provided on the surface of the partition plate. An air tank is fixedly installed inside the lower housing. A connecting pipe is connected to the output end of the air tank. The end of the connecting pipe away from the air tank passes through the through hole and is connected to the air supply pipe. An electrically controlled one-way valve is provided on the air supply pipe.

[0012] In a preferred embodiment of this utility model, a vent is provided on the left side of the electrical cabinet, and a return pipe is connected inside the vent. A solenoid valve is installed at one end of the return pipe, and the other end of the return pipe extends into the interior of the gas storage tank. A one-way valve is installed on the return pipe.

[0013] Compared with the prior art, the present invention has the following advantages: 1. This positive pressure type electrical cabinet explosion-proof device, by setting up an elastic airbag that can always be inflated, together with the arc-shaped metal spring, continuously provides stable contact pressure for the sealing strip. Even if the sealing strip shows slight aging due to long-term use, the elastic restoring ability of the metal spring and the supporting effect of the elastic airbag can compensate for the loss of elasticity of the sealing strip, maintain the tight contact between the sealing strip and the contact surface, and ensure the sealing performance of the electrical cabinet.

[0014] 2. The positive pressure type electrical cabinet explosion-proof device automatically contracts when the internal temperature of the cabinet rises to a set value through the memory metal frame, further squeezing the sealing strip to enhance the sealing effect, avoid the problem of the sealing gap increasing due to temperature changes, and delay the decay of sealing performance.

[0015] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings. Attached Figure Description

[0016] In the attached diagram: Figure 1 This is a schematic diagram of the front structure of the electrical cabinet of this utility model; Figure 2 This is a schematic diagram of the side structure of the electrical cabinet of this utility model; Figure 3 This is a schematic diagram of the internal structure of the electrical cabinet of this utility model; Figure 4 This is a disassembled schematic diagram of the internal installation structure of the electrical cabinet of this utility model; Figure 5 for Figure 4 Enlarged schematic diagram of the structure at point A in the middle; Figure 6 This is a schematic diagram of the internal structure of the lower housing of this utility model.

[0017] In the diagram: 1. Electrical cabinet; 101. Inner cabinet; 102. Partition; 103. Load-bearing frame; 104. Connecting frame; 105. Mounting plate; 106. Electrical components; 107. Limiting frame; 108. Elastic airbag; 109. Air supply pipe; 110. Memory metal frame; 111. Metal spring; 112. Sealing strip; 2. Cabinet door; 3. Glass door; 4. Lower cabinet; 401. Divider plate; 402. Through hole; 403. Air tank; 404. Connecting pipe; 405. Return pipe; 406. One-way valve; 407. Solenoid valve. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate this utility model.

[0019] Example 1 To address the problem that the sealing strips of existing positive pressure electrical cabinets age after prolonged use, resulting in a decrease in the sealing effect, such as... Figures 1 to 6 As shown, a positive pressure type explosion-proof device for electrical cabinets includes an electrical cabinet 1 and a cabinet door 2 hinged to the front of the electrical cabinet 1. A glass door 3 is installed at the center of the front of the cabinet door 2. The glass door 3 is made of tempered explosion-proof glass. An inner cabinet 101 is connected inside the electrical cabinet 1. An inner door is hinged to the front of the inner cabinet 101. A sealing strip 112 is installed on the inner wall of the inner door. An explosion-proof sealing mechanism is provided on the inner wall of the inner cabinet 101.

[0020] The sealing mechanism includes a limiting frame 107, an elastic airbag 108, an air supply pipe 109, and a metal spring 111. The limiting frame 107 is fixedly connected to the inner wall of the inner cabinet 101. The elastic airbag 108 is fixedly connected to the inner wall of the limiting frame 107. The air supply pipe 109 is fixedly connected to the back of the elastic airbag 108. The metal spring 111 is fixedly connected to the side of the elastic airbag 108 away from the limiting frame 107. The metal spring 111 is made of spring steel, has an arc-shaped structure, and has elastic reset capability. The elastic airbag 108 is filled with nitrogen. The micro protrusions on the outer wall of the metal spring 111 are tightly fitted with the sealing strip 112.

[0021] A lower housing 4 is fixedly installed at the bottom of the electrical cabinet 1. The lower housing 4 is connected to the bottom of the electrical cabinet 1 through a partition plate 401. A through hole 402 is opened on the surface of the partition plate 401. An air tank 403 is fixedly installed inside the lower housing 4. A connecting pipe 404 is connected to the output end of the air tank 403. The end of the connecting pipe 404 away from the air tank 403 passes through the through hole 402 and is connected to the air supply pipe 109. An electrically controlled one-way valve is installed on the air supply pipe 109. A vent is opened on the left side of the electrical cabinet 1. A return pipe 405 is connected inside the vent. A solenoid valve 407 is installed at one end of the return pipe 405. The other end of the return pipe 405 extends into the interior of the air tank 403. A one-way valve 406 is installed on the return pipe 405.

[0022] The inner wall of the inner cabinet 101 is fixedly connected to the left and right sides of the inner wall with a load-bearing frame 103. The inner wall of the load-bearing frame 103 is fixedly connected to a partition 102 and a connecting frame 104. The inner wall of the connecting frame 104 is fixedly connected to a mounting plate 105. Electrical components 106 are installed on the back of the mounting plate 105.

[0023] Example 2 Based on Example 1, in order to further enhance the sealing performance of the sealing strip, a memory metal frame 110 is connected to the inner wall of the inner cabinet 101. The memory metal frame 110 is located between the elastic airbag 108 and the sealing strip 112. The phase change temperature of the memory metal frame 110 is set to 55°C. When the internal temperature of the cabinet rises to 55°C due to the heating of electrical components, the memory metal frame automatically contracts.

[0024] The 110 memory metal frame is made of titanium-nickel alloy (Ti-50.8at%Ni). The phase change temperature is set at 55℃±2℃, the shrinkage rate is 8-10%, and the recovery rate is not less than 98%. The phase change temperature of 55℃ is compatible with the normal operating heating range of electrical components. When the internal temperature of the cabinet reaches this value, the frame shrinks, which can cause the sealing strip to tighten, enhancing the sealing effect. The 8-10% shrinkage rate ensures sufficient tightening force, while the ≥98% recovery rate ensures that the frame returns to its initial shape after the temperature drops, without affecting the normal opening and closing of the cabinet door.

[0025] The elastic airbag 108 is made of aging-resistant nitrile rubber, the metal spring 111 is made of 65Mn spring steel with a thickness of 0.8-1mm. The arc radius is controlled between R50-R80mm, and the elastic deformation range is ±0.5mm. The sealing strip 112 is made of fluororubber with a cross-sectional dimension of 10mm×8mm. The air tank 403 is made of Q235 carbon steel, the connecting pipe 404 is made of 304 stainless steel, the valve body of the electrically controlled check valve is made of brass, the seal is made of nitrile rubber, and the nominal diameter is DN8. The return pipe 405 is made of 304 stainless steel, and the interface with the air tank and electrical cabinet adopts a double compression fitting sealing structure. The solenoid valve 407 is a two-position two-way direct-acting solenoid valve with a valve body made of 304 stainless steel and a seal made of fluororubber. The check valve 406 adopts a vertical lifting structure with a valve body made of brass and a seal made of nitrile rubber.

[0026] The inner cabinet 101 is equipped with a high-precision pressure sensor with a range of 0-0.1MPa and an accuracy of ±0.2%FS. It collects the internal air pressure value in real time and transmits it to the controller. The controller is a PLC controller, model S7-200SMART.

[0027] When the pressure sensor detects that the air pressure in the inner cabinet is lower than 0.03MPa, the controller outputs a signal to open the outlet valve of the air tank 403 and the electrically controlled check valve on the air supply pipe 109, while adjusting the valve opening to increase the air supply flow rate; when the air pressure rises back to 0.035MPa, the valve opening is reduced to decrease the air supply flow rate; when the air pressure reaches 0.04MPa, the electrically controlled check valve and the outlet valve of the air tank are closed to stop the air supply.

[0028] When the gas pressure in the inner cabinet expands due to the heating of electrical components or when the amount of gas replenished exceeds 0.04MPa, the controller controls the solenoid valve 407 on the return pipe 405 to open, and the excess gas flows into the gas storage tank through the return pipe; when the gas pressure drops to 0.035MPa, the solenoid valve closes and the gas return stops.

[0029] A pressure sensor is also installed inside the gas storage tank, with a range of 0-0.2MPa and an accuracy of ±0.2%FS. When the gas pressure inside the storage tank is lower than 0.08MPa, the controller triggers an audible and visual alarm to issue a low-pressure alarm, reminding staff to replenish the storage tank with protective gas in time. When the gas pressure inside the storage tank is higher than 0.15MPa, a high-pressure alarm is triggered to prevent the storage tank from being damaged by overpressure.

[0030] A temperature sensor is installed inside the cabinet, with a range of -20℃ to 100℃ and an accuracy of ±0.5℃, to monitor the internal temperature in real time and transmit the data to the controller.

[0031] When the temperature sensor detects that the temperature of the inner cabinet has risen to 55℃, the controller records the temperature data and monitors the sealing status at the sealing strip. If the sealing gap is detected to be increasing, the controller does not need to perform any additional operation. It relies on the shrinkage of the memory metal frame to tighten the sealing strip and enhance the sealing effect. If the temperature continues to rise to 60℃, the controller triggers the audible and visual alarm to issue a high temperature alarm, reminding staff to check whether the electrical components are overheating abnormally.

[0032] When the temperature drops below 50℃, the controller monitors whether the memory metal skeleton has returned to its initial shape. If the skeleton has not fully returned to its original shape and the sealing gap is greater than 0.1mm, the controller can briefly open the air supply pipe's electrically controlled one-way valve to slightly increase the pressure inside the elastic airbag 108, assisting in pushing the metal spring to ensure that the sealing strip fits tightly.

[0033] Assembly of Electrical Cabinet 1: First, fix the main frame of electrical cabinet 1 in the preset installation position to ensure the cabinet is placed stably. Next, weld the load-bearing frame 103 to the left and right sides of the inner wall of the inner cabinet 101. The load-bearing frame 103 is made of Q235 steel plate with a thickness of 5mm to ensure sufficient load-bearing capacity. Then, fix the partition 102 and the connecting frame 104 to the inner wall of the load-bearing frame 103 with bolts. The spacing of the partition 102 is adjusted according to the height of the electrical components 106 to be installed, generally set to 30-50cm. The connecting frame 104 is connected to the load-bearing frame 103 with M8 bolts, and the tightening torque is controlled at 25-30N·m to ensure a firm connection. Finally, fix the mounting plate 105 to the inner wall of the connecting frame 104, and then install the electrical components 106 on the back of the mounting plate 105 with screws. During the installation process, ensure that there is a heat dissipation gap of at least 2cm between the electrical components 106.

[0034] First, the limiting frame 107 is fixed to the inner wall of the inner cabinet 101 by welding. The limiting frame 107 is made of stainless steel and its size is adapted to the inner wall of the inner cabinet 101 to ensure a tight fit. Then, the elastic airbag 108 is attached to the inner wall of the limiting frame 107. The elastic airbag 108 is made of aging-resistant rubber. Before attachment, the inner wall of the limiting frame 107 needs to be sanded and rust-free, and a special adhesive needs to be applied to ensure that the elastic airbag 108 is firmly connected to the limiting frame 107 and there is no risk of falling off. Next, one end of the air supply pipe 109 is welded to the interface on the back of the elastic airbag 108, and the other end is left outside the inner cabinet 101 for easy connection to the connecting pipe 404 later. The air supply pipe 109 is made of copper pipe with a diameter of 8mm, and an electrically controlled one-way valve is installed on the air supply pipe 109. The electrically controlled one-way valve is a DN8 model to ensure normal opening and closing. Next, the metal spring piece 111 is fixed to the side of the elastic airbag 108 away from the limiting frame 107 by rivets. The metal spring piece 111 is made of spring steel and has an arc-shaped structure with an arc controlled between R50 and R80. The rivet spacing is set to 20cm to ensure that the metal spring piece 111 is fixed stably and has good elastic reset capability. Finally, a memory metal frame 110 is installed on the inner wall of the inner cabinet 101, between the elastic airbag 108 and the sealing strip 112. The memory metal frame 110 is made of titanium-nickel alloy and is connected to the inner wall of the inner cabinet 101 by buckles. Its phase change temperature is preset to 55℃. During installation, it is necessary to ensure that the memory metal frame 110, the elastic airbag 108, and the sealing strip 112 are all in close contact.

[0035] Cabinet door 2 is hinged to the front of electrical cabinet 1 using stainless steel hinges to ensure smooth rotation. The gap between cabinet door 2 and electrical cabinet 1 is controlled at 1-2mm when closed. A mounting hole for a glass door 3 is made in the center of the front of cabinet door 2. The tempered explosion-proof glass door 3 is inserted into the mounting hole. A weather-resistant rubber sealing strip is used to seal the gap between the glass door 3 and cabinet door 2 to ensure no gas leakage. A lower enclosure 4 is welded to the bottom of electrical cabinet 1. The lower enclosure 4 is made of cold-rolled steel plate with a thickness of 4mm. The lower enclosure 4 is connected to the bottom of electrical cabinet 1 via a partition plate 401. A 10mm diameter through hole 402 is formed on the surface of the partition plate 401 for a connecting pipe 404 to pass through. An air tank 403 is fixedly installed inside the lower housing 4. The air tank 403 is made of carbon steel, and its volume is set according to the size of the electrical cabinet 1, generally 50-100L. The air tank 403 is connected to the inner wall of the lower housing 4 by a bracket, and the bracket is fixed to the lower housing 4 by welding. One end of the connecting pipe 404 is welded to the output end of the air tank 403, and the other end passes through the through hole 402 on the partition plate 401 and is connected to the air supply pipe 109 by thread. The connecting pipe 404 is made of stainless steel and has a diameter of 8mm. After connection, the airtightness of the interface must be tested to ensure that there is no air leakage. A vent is made on the left side of electrical cabinet 1. One end of the return pipe 405 is installed in the vent and sealed with a gasket. The other end extends into the gas storage tank 403. A one-way valve 406 and a solenoid valve 407 are installed on the return pipe 405 in sequence. The one-way valve 406 is a DN8 model to ensure that gas can only flow from electrical cabinet 1 to gas storage tank 403. The solenoid valve 407 is a DN8 model and is used to control the opening and closing of the return pipe 405.

[0036] Close the inner door and cabinet door 2. Inflate the elastic airbag 108 with nitrogen gas through the gas tank 403, controlling the inflation pressure at 0.02-0.03 MPa. Observe whether the elastic airbag 108 expands evenly and whether the micro protrusions on the outer wall of the metal spring 111 are tightly fitted with the sealing strip 112. Use an airtightness tester to test the electrical cabinet 1 and the inner cabinet 101. Set the test pressure to 0.05 MPa and the pressure holding time to 30 minutes. If the pressure drop does not exceed 0.002 MPa, the sealing performance is qualified. If the pressure drop exceeds the standard, check whether the elastic airbag 108 is damaged and whether all connection interfaces are well sealed until the sealing performance meets the standard.

[0037] The internal temperature of the inner cabinet 101 is gradually increased to 55°C using a heating device. The shape memory metal frame 110 is then observed to automatically contract, and its contraction is checked to ensure it can further adhere to the sealing strip 112, enhancing the sealing effect. After the temperature drops to room temperature, the shape memory metal frame 110 is checked to see if it returns to its initial shape. If the shape memory metal frame 110 does not contract when the temperature reaches 55°C or does not return to its initial shape after the temperature drops to room temperature, it needs to be replaced to ensure its temperature response performance is normal.

[0038] Open the valve of the gas storage tank 403 to supply gas to the inner cabinet 101 through the connecting pipe 404 and the gas supply pipe 109, maintaining the internal gas pressure of the inner cabinet 101 at 0.03-0.04 MPa. When the internal gas pressure of the inner cabinet 101 exceeds 0.04 MPa, open the solenoid valve 407 and observe whether the gas can smoothly flow back to the gas storage tank 403 through the return pipe 405, and whether the one-way valve 406 can effectively prevent the gas from flowing backward. Repeat the gas pressure increase and return cycle test 3-5 times to ensure that the gas pressure regulation system works stably and that the valves operate accurately and reliably.

[0039] Working principle: When the device is operating normally and the internal temperature of the inner cabinet 101 is below 55°C, the nitrogen filling the elastic airbag 108 keeps it inflated, pushing the metal spring 111 outward. The micro-protrusions on the outer wall of the metal spring 111 fit tightly against the sealing strip 112 on the inner wall of the inner door, forming the first line of defense to prevent flammable and explosive gases from entering the inner cabinet 101. At the same time, the limiting frame 107 limits the elastic airbag 108, preventing it from over-expanding and causing structural damage, thus ensuring a stable seal.

[0040] The sealing enhancement mechanism during temperature rise: When the electrical components 106 inside the inner cabinet 101 generate heat, causing the internal temperature of the inner cabinet 101 to rise to 55°C, the shape memory metal frame 110 undergoes a phase change and automatically contracts. Since the shape memory metal frame 110 is located between the elastic airbag 108 and the sealing strip 112, its contraction will generate an inward squeezing force on the sealing strip 112, making the sealing strip 112 even tighter against the contact surface between the inner door and the inner cabinet 101, reducing the sealing gap, enhancing the sealing effect, forming a second sealing defense line, effectively coping with the slight deformation of the sealing strip 112 that may be caused by temperature rise, and avoiding a decrease in sealing performance.

[0041] If, during long-term use, the elastic airbag 108 experiences slight leakage, causing a drop in internal pressure and affecting the sealing effect, air can be replenished through the air tank 403. Open the valve on the air tank 403 and the electrically controlled check valve on the air replenishment pipe 109. Gas from the air tank 403 enters the elastic airbag 108 through the connecting pipe 404 and the air replenishment pipe 109 until the internal pressure of the elastic airbag 108 returns to the normal range of 0.02-0.03 MPa. Then close the electrically controlled check valve and the valve on the air tank 403 to ensure the elastic airbag 108 remains in a good expanded and sealed state.

[0042] During operation of the internal cabinet pressure maintenance device, to ensure that the interior of the internal cabinet 101 is always under positive pressure and to prevent the entry of flammable and explosive gases from the outside, the gas storage tank 403 continuously supplies gases such as nitrogen, dry air, or other inert or clean gases into the internal cabinet 101 through the connecting pipe 404 and the gas supply pipe 109. The internal pressure of the internal cabinet 101 is monitored in real time by a pressure sensor. When the internal pressure of the internal cabinet 101 is lower than 0.03 MPa, the gas storage tank 403 is controlled to increase the gas output; when the internal pressure of the internal cabinet 101 is higher than 0.04 MPa, the gas output is reduced, so that the internal pressure of the internal cabinet 101 is stabilized within the safe range of 0.03-0.04 MPa.

[0043] The principle of gas recovery and utilization is as follows: When the internal gas pressure of the inner cabinet 101 exceeds the upper limit of 0.04 MPa due to excessive gas replenishment or gas expansion caused by the heating of electrical components 106, the controller controls the solenoid valve 407 on the return pipe 405 to open. Excess gas inside the inner cabinet 101 flows to the gas storage tank 403 through the return pipe 405. The one-way valve 406 on the return pipe 405 prevents gas in the gas storage tank 403 from flowing back into the inner cabinet 101, ensuring one-way gas return. Through gas recovery and utilization, not only can the internal gas pressure of the inner cabinet 101 be maintained stably, but gas waste can also be reduced, operating costs lowered, and the potential environmental impact of direct gas emissions avoided.

Claims

1. A positive pressure type explosion-proof device for electrical cabinets, comprising an electrical cabinet (1) and a cabinet door (2) hinged to the front of the electrical cabinet (1), characterized in that: The electrical cabinet (1) is internally connected to an inner cabinet (101). The front of the inner cabinet (101) is hinged to an inner door. A sealing strip (112) is installed on the inner wall of the inner door. An explosion-proof sealing mechanism is provided on the inner wall of the inner cabinet (101). The sealing mechanism includes a limiting frame (107), an elastic airbag (108), an air supply pipe (109), and a metal spring (111). The limiting frame (107) is fixedly connected to the inner wall of the inner cabinet (101). The elastic airbag (108) is fixedly connected to the inner wall of the limiting frame (107). The air supply pipe (109) is fixedly connected to the back of the elastic airbag (108). The metal spring (111) is fixedly connected to the side of the elastic airbag (108) away from the limiting frame (107).

2. The positive pressure type explosion-proof device for electrical cabinets according to claim 1, characterized in that: The metal spring (111) is made of spring steel and has an arc-shaped structure with elastic restoring capability. The elastic airbag (108) is filled with nitrogen gas. The micro protrusions on the outer wall of the metal spring (111) are tightly fitted with the sealing strip (112).

3. The positive pressure type explosion-proof device for electrical cabinets according to claim 1, characterized in that: The inner wall of the inner cabinet (101) is connected to a memory metal frame (110). The memory metal frame (110) is located between the elastic airbag (108) and the sealing strip (112). The phase change temperature of the memory metal frame (110) is set to 55°C. When the internal temperature of the cabinet rises to 55°C due to the heating of electrical components, the memory metal frame (110) automatically contracts.

4. The positive pressure type explosion-proof device for electrical cabinets according to claim 1, characterized in that: The inner wall of the inner cabinet (101) is fixedly connected to the left and right sides of the inner wall of the cabinet. The inner wall of the load-bearing frame (103) is fixedly connected to the partition (102) and the connecting frame (104). The inner wall of the connecting frame (104) is fixedly connected to the mounting plate (105). Electrical components (106) are installed on the back of the mounting plate (105).

5. The positive pressure type explosion-proof device for electrical cabinets according to claim 1, characterized in that: A glass door (3) is installed at the center of the front of the cabinet door (2), and the glass door (3) is made of tempered explosion-proof glass.

6. The positive pressure type explosion-proof device for electrical cabinets according to claim 1, characterized in that: The bottom of the electrical cabinet (1) is fixedly installed with a lower box (4). The lower box (4) is connected to the bottom of the electrical cabinet (1) through a partition plate (401). The surface of the partition plate (401) is provided with a through hole (402). A gas storage tank (403) is fixedly installed inside the lower box (4). The output end of the gas storage tank (403) is connected to a connecting pipe (404). The end of the connecting pipe (404) away from the gas storage tank (403) passes through the through hole (402) and is connected to the gas supply pipe (109). An electrically controlled one-way valve is provided on the gas supply pipe (109).

7. The positive pressure type explosion-proof device for electrical cabinets according to claim 6, characterized in that: The electrical cabinet (1) has a vent hole on its left side. A return pipe (405) is connected inside the vent hole. A solenoid valve (407) is installed at one end of the return pipe (405). The other end of the return pipe (405) extends into the interior of the gas storage tank (403). A one-way valve (406) is installed on the return pipe (405).

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