An explosion-proof voltage transformer cabinet

Abstract

The invention discloses an explosion-proof voltage transformer cabinet, and relates to the technical field of voltage transformer cabinets. The invention comprises a switch door, on which a common password lock and a reinforced password lock are installed; and an upper pressure relief box is also included, in which an air bag which is only connected with the inside of a PT cabinet is installed, and in an initial state, the air bag is in a contracted state, and a push switch is also installed in the upper pressure relief box, and the push switch is electrically connected with the reinforced password lock. When the air pressure inside the PT cabinet rises, the air bag expands to a predetermined position inside the upper pressure relief box, and contacts the push switch to energize the reinforced password lock, and at this time, the reinforced password lock is in a working state; in the invention, the common password lock and the reinforced password lock are used to solve the problem of insufficient stability of the switch door of the PT cabinet during explosion, and the trouble in normal application can be avoided, and fire extinguishing can be automatically triggered at the same time, which can avoid deflagration on the one hand, and extinguish the fire as quickly as possible to reduce losses on the other hand.

Description

Technical Field

[0001] The invention relates to the technical field of voltage transformer cabinets, in particular to an explosion-proof voltage transformer cabinet. Background Art

[0002] Voltage transformer cabinet, usually called PT cabinet, is a device for installing voltage transformers for measurement, protection and synchronization purposes. Common explosion-proof types of PT cabinets include flameproof type and increased safety type. The flameproof type means that when an explosion occurs inside the equipment, the flame and explosives cannot be transmitted to the outside through the flameproof shell of the equipment.

[0003] The partition material of the explosion-proof PT cabinet is usually aluminum alloy profile, which has excellent explosion-proof performance. However, in order to open and close the PT cabinet, the cabinet body must be equipped with a switch door, and the switch door is the weakest part of the entire explosion-proof PT cabinet. Generally, the switch door will be locked with a set of electromagnetic locks. However, when the explosion is about to occur, the internal temperature of the PT cabinet rises rapidly, causing the internal air pressure to rise accordingly. Once the impact force generated by the explosion is very large, the switch door locked by a single set of electromagnetic locks is less safe from the explosion impact. Setting multiple electromagnetic locks requires locking multiple electromagnetic locks every time the switch door is closed, which is more troublesome. Summary of the invention

[0004] The object of the present invention is to provide an explosion-proof voltage transformer cabinet to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides an explosion-proof voltage transformer cabinet, comprising a switch door, on which a common password lock and a reinforced password lock are installed;

[0006] It also includes an upper pressure relief box, in which an air bag connected only to the PT cabinet is installed. In the initial state, the air bag is in a contracted state. A push switch is also installed in the upper pressure relief box, and the push switch is electrically connected to the reinforced password lock. When the air pressure inside the PT cabinet rises and the air bag expands to a predetermined position inside the upper pressure relief box, it contacts the push switch to power on the reinforced password lock. At this time, the reinforced password lock is in a working state.

[0007] Furthermore, it also includes a lower pressure relief box, and the switch door is divided into an upper sealed door and a lower sealed door. Both the upper sealed door and the lower sealed door are equipped with common password locks and reinforced password locks. The press switch in the upper pressure relief box triggers the operation of one of the reinforced password locks on the upper sealed door, and the press switch in the lower pressure relief box controls the operation of one of the reinforced password locks on the lower sealed door.

[0008] Furthermore, the upper sealed door and the lower sealed door are both hinged on an explosion-proof voltage transformer cabinet through three sets of hinges, and there are two reinforced password locks on the upper sealed door and the lower sealed door. The two reinforced password locks are mirror-imaged about the hinge at the middle position, and the spacing between the reinforced password lock and its two adjacent hinges is equal.

[0009] Furthermore, a pressure relief groove is provided on the inner wall of the upper pressure relief box, a push switch is provided in the pressure relief groove, a slider is slidably installed in the pressure relief groove, the slider is connected to the airbag, and when the airbag expands and drives the slider to slide horizontally, the push switch will be pressed to control the operation of the reinforced password lock.

[0010] Furthermore, a transmission rod is slidably mounted on the slider, the transmission rod is connected to the slider via a spring, a low-friction ball is rotatably mounted on the end of the transmission rod, and the low-friction ball is in contact with the inner wall of the pressure relief groove in the initial state of the spring.

[0011] Furthermore, it also includes a top partition, on which a dry powder box is installed, in which dry powder is stored, and in which a powder outlet extending vertically and a sliding cavity communicating with the powder outlet is provided;

[0012] It also includes a blocking plate located directly below the dry powder box and blocking the bottom of the dry powder box. The blocking plate can be slidably arranged in the sliding cavity. When the airbag expands due to heat, the blocking plate is pulled to slide in the sliding cavity through the transmission component so that the blocking plate and the bottom of the dry powder box are offset so that the dry powder falls into an explosion-proof voltage transformer cabinet.

[0013] Furthermore, the transmission assembly includes a pull rope connected to the sealing plate, and a sliding opening is provided on the top of the upper pressure relief box. The pull rope passes through the sliding opening and extends into the upper pressure relief box and is fixedly connected to the sliding block.

[0014] Furthermore, a contact switch is installed on the side of the sliding cavity away from the pull rope, and the blocking plate is in conflict with the contact switch in the initial state.

[0015] Furthermore, one end of the slider and the end of the sealing plate away from the pull rope are connected to a reset rope, and a winding chamber is provided in the upper pressure relief box and the top partition, and a winding roller is rotatably installed in the winding chamber, the reset rope is wound on the winding roller, and a spring device is installed on the winding roller. When the slider slides horizontally due to the expansion of the airbag, the reset rope is pulled out from the winding roller, and at this time the spring device is compressed to accumulate elastic potential energy.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. In the present invention, the upper pressure relief box, the middle pressure relief box and the lower pressure relief box respectively control the common password lock and the reinforced password lock to work together, which improves the stability of the PT cabinet door opening and closing when the PT explodes without affecting normal use, thereby improving the explosion-proof effect, and the structure is simple while the safety factor is high.

[0018] 2. In the present invention, the dry powder in the dry powder box can participate in the fire extinguishing of the PT in the PT cabinet and can be automatically triggered, which can avoid deflagration on the one hand and extinguish the fire as quickly as possible to reduce losses on the other hand. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the PT cabinet in Example 1;

[0020] Figure 2 This is a schematic diagram of the structure inside the PT cabinet in Example 1;

[0021] Figure 3 It is a right side view of the PT cabinet in the first embodiment;

[0022] Figure 4 It is a schematic diagram of the structure inside the upper pressure relief box in the first embodiment;

[0023] Figure 5 for Figure 4 A magnified view of the structure at center A;

[0024] Figure 6 It is a structural schematic diagram of the PT cabinet in the second embodiment;

[0025] Figure 7 It is a schematic diagram of the structure of the fire extinguishing assembly in the second embodiment.

[0026] In the figure: 1. frame; 2. side partition; 3. upper sealing door; 4. lower sealing door; 5. common password lock; 6. reinforced password lock; 7. top partition; 8. sliding mouth; 9. harness hole; 10. vent; 11. voltage transformer; 12. upper air vent; 13. middle air vent; 14. lower air vent; 15. crossbeam; 16. upper pressure relief box; 17. middle pressure relief box; 18. lower pressure relief box; 19. air bag; 20. pressure relief groove; 21. slider; 22. push switch; 23. low friction ball; 24. spring; 25. transmission rod; 26. dry powder box; 27. dry powder; 28. blocking plate; 29. ​​contact switch; 30. powder outlet; 31. pull rope; 32. pulley; 33. sliding cavity; 34. ball seat. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example

[0028] See also Figure 1 and Figure 2 A explosion-proof voltage transformer cabinet comprises a frame 1 and side partitions 2 integrally connected to the left and right sides of the frame 1, the back of the PT cabinet is an integrally connected back partition, the front of the frame 1 is a switch door, the switch door is hinged on the PT cabinet, and a common password lock 5 and a reinforced password lock 6 are installed on the switch door. The common password lock 5 is in a continuous working state, and the reinforced password lock 6 is in a standby state under normal conditions.

[0029] Three voltage transformers 11 are installed in the PT cabinet. The three voltage transformers 11 are placed in sequence from top to bottom. An upper air vent 12 is opened on the back partition at a height corresponding to the upper voltage transformer 11 .

[0030] See also Figure 3 and Figure 4 The PT cabinet also includes an upper pressure relief box 16, in which an air bag 19 connected only to the inside of the PT cabinet is installed. In the initial state, the air bag 19 is in a contracted state. A push switch 22 is also installed in the upper pressure relief box 16. The push switch 22 is electrically connected to the reinforced password lock 6. When the air pressure inside the PT cabinet rises and the air bag 19 expands to a predetermined position inside the upper pressure relief box 16, it contacts the push switch 22 to energize the reinforced password lock 6. At this time, the reinforced password lock 6 is in a working state.

[0031] Specifically, the upper pressure relief box 16 is integrally formed with the PT cabinet, and the upper pressure relief box 16 closes the upper air leakage port 12. The airbag 19 is made of nylon, polyester, polyamide or other materials coated with silicone coating on the surface. The airbag 19 is in the air leakage cavity provided in the upper pressure relief box 16, and its deformation process is guided by the air leakage cavity. The end of the airbag 19 is fixed on the back partition and connected with the PT cabinet. When the PT fails and short-circuits and catches fire, the temperature inside the PT cabinet will rise rapidly, and the air will expand due to heat, causing the air pressure inside the PT cabinet to rise rapidly. , and then the expanded air enters the airbag 19 through the upper air vent 12 to expand the airbag 19, and then triggers the press switch 22 to make the reinforced password lock 6 work during the process of the airbag 19 expanding and changing in volume. At this time, the door is locked on the PT cabinet through the common password lock 5 and the reinforced password lock 6, which is more stable, so as to cope with the explosion that may be caused by the combustion of PT, and improve the explosion-proof performance of the PT cabinet. At the same time, there is no need to manually close the reinforced password lock 6 during normal use, so that the opening and closing process of the PT cabinet will not become more troublesome.

[0032] Furthermore, a harness hole 9 is provided on the side partition 2, and the wiring for connecting the voltage transformer 11 enters from the harness hole 9 on one side and passes through the harness hole 9 on the other side. The actual height of the harness hole 9 is not limited and only needs to meet the installation standard of the PT cabinet wiring hole.

[0033] In addition, a plurality of vent holes 10 are provided on the side partition plate 2 to assist ventilation in the PT cabinet, which is beneficial to the heat dissipation of the voltage transformer to a certain extent. The number of vent holes 10 is small and the aperture is small. When a fire occurs in the PT cabinet, the exhaust rate is slow, and the expansion process of the airbag 19 is less affected. The normal operation of the present invention is guaranteed under the premise of ensuring a certain degree of heat dissipation.

[0034] See also Figure 3 Furthermore, the PT cabinet also includes a lower pressure relief box 18, and the switch doors are divided into an upper sealed door 3 and a lower sealed door 4. Both the upper sealed door 3 and the lower sealed door 4 are equipped with a common password lock 5 and a reinforcement password lock 6. The press switch 22 in the upper pressure relief box 16 triggers one of the reinforcement password locks 6 on the upper sealed door 3 to work, and the press switch 22 in the lower pressure relief box 18 controls one of the reinforcement password locks 6 on the lower sealed door 4 to work.

[0035] See also Figure 2A lower air vent 14 is provided on the back partition at a height position corresponding to the lower voltage transformer 11, and the lower pressure relief box 18 seals the lower air vent 14. The lower pressure relief box 18 is integrally formed with the PT cabinet, and the internal structure of the lower pressure relief box 18 is consistent with the internal structure of the upper pressure relief box 16. When the push switch 22 in the upper pressure relief box 16 is triggered, the push switch 22 controls the reinforced password lock 6 located above the upper sealing door 3 to work. When the push switch 22 in the lower pressure relief box 18 is triggered, the push switch 22 controls the reinforced password lock 6 located below the lower sealing door 4 to work. At this time, the upper sealing door 3 and the lower sealing door 4 are locked on the PT cabinet together by a common password lock 5 and a reinforced password lock 6.

[0036] For further information, see Figure 2 and Figure 3 A middle air relief port 13 is provided at the middle height of the back partition, and a middle pressure relief box 17 is integrally formed on the PT cabinet. The middle pressure relief box 17 is located between the upper pressure relief box 16 and the lower pressure relief box 18. The internal structure of the middle pressure relief box 17 is consistent with that of the upper pressure relief box 16. The difference is that two push switches 22 are provided in the middle pressure relief box 17. The two push switches 22 are respectively used to control the two reinforced password locks 6 located in the middle of the upper sealing door 3 and the lower sealing door 4.

[0037] Since the main factor of the explosion in the PT cabinet is the fire caused by the short circuit fault of the PT, an upper pressure relief box 16, a middle pressure relief box 17 and a lower pressure relief box 18 are respectively arranged at the heights corresponding to the three voltage transformers 11, and the air bag 19 is close to the PT cabinet. The side is fitted along the inner contours of the upper pressure relief box 16, the middle pressure relief box 17 and the lower pressure relief box 18, and is fixed by positioning parts including nuts, etc. The upper pressure relief box 16, the middle pressure relief box 17 and the lower pressure relief box 18 and the air bag 19 are fixed to the upper pressure relief box 16, the middle pressure relief box 17 and the lower pressure relief box 18. The size of the bag 19 is only for illustration in the accompanying drawings. Its actual size and proportion can be selected according to the material, combustion characteristics, gas release rate, etc. of the voltage transformer 11 in the PT cabinet. This application does not impose any restrictions. When any PT explodes, the reinforced password locks 6 of similar heights are triggered to work, thereby ensuring the stability of the upper sealing door 3 and the lower sealing door 4 close to the explosion position. A crossbeam 15 is integrally arranged on the back partition at the upper air vent 12, the middle air vent 13 and the lower air vent 14 to increase the strength.

[0038] For further information, see Figure 1The upper sealing door 3 and the lower sealing door 4 are both hinged on an explosion-proof voltage transformer cabinet through three sets of hinges, and the number of reinforced password locks 6 on the upper sealing door 3 and the lower sealing door 4 is two, and the two reinforced password locks 6 are mirror-imaged about the hinge at the middle position, and the spacing between the reinforced password lock 6 and its two adjacent hinges is equal, which can improve the stability of the upper sealing door 3 or the lower sealing door 4 and the PT cabinet at the installation hinge to avoid the hinge installation position becoming a breakthrough point for explosion. At the same time, the reinforced password lock 6 does not work in the normal state and will not affect the operation of the hinge.

[0039] See also Figure 4 and Figure 5 A pressure relief groove 20 is provided on the inner wall of the upper pressure relief box 16, a push switch 22 is provided in the pressure relief groove 20, a slider 21 is slidably installed in the pressure relief groove 20, and the slider 21 is connected to the airbag 19. When the airbag 19 expands and drives the slider 21 to slide horizontally, the push switch 22 will be pressed to control the operation of the reinforced password lock 6.

[0040] The width of the pressure relief groove 20 is slightly larger than the slider 21, and the slider 21 can only slide horizontally in the pressure relief groove 20 along the length direction of the pressure relief groove 20. After the slider 21 slides to the right to trigger the press switch 22, the left side of the press switch 22 is lifted up. When the airbag 19 returns to its initial state, the press switch 22 can close the reinforced password lock 6 again.

[0041] In this embodiment, a transmission rod 25 is slidably mounted on the slider 21, and the transmission rod 25 is connected to the slider 21 through a spring 24. A low-friction ball 23 is rotatably mounted on the end of the transmission rod 25. In the initial state of the spring 24, the low-friction ball 23 is in contact with the inner wall of the pressure relief groove 20.

[0042] A ball seat 34 is installed at the bottom of the transmission rod 25, and the low-friction ball 23 is rotatably installed on the ball seat 34. The low-friction ball 23 presses against the pressure relief groove 20 and can roll when the slider 21 moves. An assembly cavity is provided in the slider 21, and the spring 24 is connected in the assembly cavity. The transmission rod 25 can only slide vertically along the assembly cavity, which is beneficial to reducing the friction resistance encountered by the slider 21 during the sliding process, and the low-friction ball 23 can be affected by the elastic force of the spring 24. When the low-friction ball 23 rolls to the press switch 22, the elastic force of the spring 24 enables the low-friction ball 23 to press the press switch 22 so that the press switch 22 is triggered. Example

[0043] See also Figure 6 The PT cabinet further comprises a top partition 7, on which a dry powder box 26 is mounted, in which dry powder 27 is stored, and a powder outlet 30 extending vertically through the top partition 7 and a sliding cavity 33 communicating with the powder outlet 30 are provided;

[0044] In addition, the PT cabinet also includes a blocking plate 28 located directly below the dry powder box 26 and blocking the bottom of the dry powder box 26. The blocking plate 28 is slidably arranged in the sliding cavity 33. When the airbag 19 expands due to heat, the blocking plate 28 is pulled to slide in the sliding cavity 33 through the transmission component so that the blocking plate 28 and the bottom of the dry powder box 26 are offset so that the dry powder 27 falls into an explosion-proof voltage transformer cabinet.

[0045] Among them, the powder outlet 30 is located at the middle height of the top partition 7, and there is a funnel-shaped cavity inside the dry powder box 26 for accommodating dry powder 27, and the bottom of the cavity has an opening. The dry powder 27 can pass through the powder outlet 30 through the opening and enter the PT cabinet to participate in fire extinguishing. However, under normal conditions, the bottom of the powder outlet 30 is closed by a blocking plate 28. When the airbag 19 is heated and expanded, the transmission component is used to pull the blocking plate 28 to slide in the sliding cavity 33 so that the blocking plate 28 and the bottom of the dry powder box 26 are offset so that the dry powder 27 falls into an explosion-proof voltage transformer cabinet to participate in fire extinguishing. The dry powder fire extinguishing agent in the dry powder fire extinguisher is a fine solid powder formed by drying, crushing and mixing inorganic salts with fire extinguishing efficiency and a small amount of additives. This fire extinguishing agent is not conductive, so it can be safely used to extinguish fires caused by live equipment. At the same time, it relies on volatile decomposition products such as inorganic salts to suppress and negatively catalyze the free radicals generated by the object when it is on fire, so that the combustion chain is interrupted to achieve the purpose of fire extinguishing. In addition, dry powder can also adhere to the surface of the gas, forming a glass-like covering layer after a chemical reaction, isolating oxygen and achieving the effect of extinguishing the fire.

[0046] In this embodiment, see Figure 7 The transmission assembly includes a pull rope 31 connected to the blocking plate 28 , and a sliding opening 8 is opened on the top of the upper pressure relief box 16 . The pull rope 31 passes through the sliding opening 8 and extends into the upper pressure relief box 16 and is fixedly connected to the slider 21 .

[0047] The sliding port 8 is connected to the pressure relief groove 20, and the width of the blocking plate 28 matches the width of the sliding cavity 33. Figure 7 The pull rope 31 slides the blocking plate 28 to the left and right directions, and the blocking plate 28 slides until the blocking plate 28 and the dry powder box 26 are staggered, so that the dry powder 27 can enter the PT cabinet to participate in fire extinguishing.

[0048] Furthermore, a contact switch 29 is installed on the side of the sliding cavity 33 away from the pull rope 31. In the initial state, the blocking plate 28 contacts the contact switch 29, and the contact switch 29 can assist the staff in determining whether the blocking plate 28 is in the position as shown in FIG. Figure 7 The position indicated can ensure that the dry powder 27 blocks the bottom of the dry powder box 26 in the initial state. A signal light or other prompting electrical device can be connected to the contact switch 29 to assist the staff in making judgments.

[0049] A pulley 32 is installed on the back partition, and the pull rope 31 is overlapped on the pulley 32. When the pull rope 31 slides, the pulley 32 rotates, thereby reducing the friction resistance of the pull rope 31 during the sliding process.

[0050] As another preferred implementation manner of this embodiment, one end of the slider 21 and the end of the sealing plate 28 away from the pull rope 31 are connected with a reset rope, and a winding chamber is provided in the upper pressure relief box 16, the middle pressure relief box 17, the lower pressure relief box 18 and the top partition 7. A winding roller is rotatably installed in the winding chamber, the reset rope is wound on the winding roller, and a spring device is installed on the winding roller. When the slider 21 slides horizontally due to the expansion of the airbag 19, the reset rope is pulled out from the winding roller. At this time, the spring device is compressed to accumulate elastic potential energy (not shown in the figure).

[0051] The winding chamber in the top partition 7 can be set on the side close to the contact switch 29, and the winding chambers on the upper pressure relief box 16, the middle pressure relief box 17 and the lower pressure relief box 18 can be set at the position between the back partition and the pressure relief groove 20. In order to avoid the contact switch 29 affecting the connecting rope in the top partition 7, two reset ropes can be set. The two reset ropes are mirrored with respect to the contact switch 29. The clockwork device can convert the elastic potential energy into kinetic energy when the air pressure in the airbag 19 returns to its initial state, thereby pulling the blocking plate 28 or the slider 21 back to its initial position.

Claims

1. An explosion-proof voltage transformer cabinet, characterized in that: It comprises a switch door, on which a common password lock (5) and a reinforced password lock (6) are installed; The device further comprises an upper pressure relief box (16), wherein an air bag (19) connected only to the inside of the PT cabinet is installed in the upper pressure relief box (16), wherein the air bag (19) is in a contracted state in an initial state, and a push switch (22) is also installed in the upper pressure relief box (16), wherein the push switch (22) is electrically connected to the reinforced password lock (6), and when the air pressure inside the PT cabinet rises and the air bag (19) expands to a predetermined position inside the upper pressure relief box (16), the push switch (22) contacts the reinforced password lock (6), thereby energizing the reinforced password lock (6), and the reinforced password lock (6) is in a working state; The inner wall of the upper pressure relief box (16) is provided with a pressure relief groove (20), a push switch (22) is provided in the pressure relief groove (20), a slider (21) is slidably installed in the pressure relief groove (20), the slider (21) is connected to the airbag (19), and when the airbag (19) expands and drives the slider (21) to slide horizontally, the push switch (22) is pressed to control the operation of the reinforced password lock (6); It also includes a top partition (7), a dry powder box (26) is mounted on the top partition (7), dry powder (27) is stored in the dry powder box (26), and a powder outlet (30) extending vertically through the top partition (7) and a sliding cavity (33) communicating with the powder outlet (30) is formed in the top partition (7); It also includes a blocking plate (28) located directly below the dry powder box (26) and blocking the bottom of the dry powder box (26). The blocking plate (28) is slidably arranged in the sliding cavity (33). When the air bag (19) is heated and expanded, the blocking plate (28) is pulled by the transmission component to slide in the sliding cavity (33) so that the blocking plate (28) and the bottom of the dry powder box (26) are offset so that the dry powder (27) falls into an explosion-proof voltage transformer cabinet. The transmission assembly comprises a pull rope (31) connected to the sealing plate (28); a sliding opening (8) is provided at the top of the upper pressure relief box (16); the pull rope (31) passes through the sliding opening (8) and extends into the upper pressure relief box (16) and is fixedly connected to the sliding block (21).

2. An explosion-proof voltage transformer cabinet according to claim 1, characterized in that: The invention also comprises a lower pressure relief box (18), wherein the switch door is divided into an upper sealing door (3) and a lower sealing door (4), and both the upper sealing door (3) and the lower sealing door (4) are equipped with a common password lock (5) and a reinforced password lock (6), wherein a press switch (22) in the upper pressure relief box (16) triggers one of the reinforced password locks (6) on the upper sealing door (3) to operate, and a press switch (22) in the lower pressure relief box (18) controls one of the reinforced password locks (6) on the lower sealing door (4) to operate.

3. An explosion-proof voltage transformer cabinet as claimed in claim 2, characterized in that: The upper sealed door (3) and the lower sealed door (4) are both hinged to an explosion-proof voltage transformer cabinet via three sets of hinges, and the number of reinforced password locks (6) on the upper sealed door (3) and the number of reinforced password locks (6) on the lower sealed door (4) are both two, the two reinforced password locks (6) are mirror-imaged with respect to the hinge at the middle position, and the spacing between the reinforced password lock (6) and its two adjacent hinges is equal.

4. An explosion-proof voltage transformer cabinet according to claim 1, characterized in that: A transmission rod (25) is slidably mounted on the slider (21), the transmission rod (25) being connected to the slider (21) via a spring (24), a low-friction ball (23) being rotatably mounted on the end of the transmission rod (25), and the spring (24) causes the low-friction ball (23) to contact the inner wall of the pressure relief groove (20) in an initial state.

5. An explosion-proof voltage transformer cabinet according to claim 1, characterized in that: A contact switch (29) is installed on the side of the sliding cavity (33) facing away from the pull rope (31), and in an initial state, the blocking plate (28) contacts the contact switch (29).

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