Pressure relief valve

Abstract

The present application relates to the field of release valve, specifically to a pressure release valve, including valve body, the side of valve body has pressure hole, the lower end of valve body has mounting hole, the valve body is provided with the valve cavity that penetrates axially, the valve cavity is communicated with pressure hole and mounting hole, the upper end of valve body is equipped with adjusting bolt, the lower end of adjusting bolt is equipped with spring cover, spring cover is equipped with reset spring in, the lower end of reset spring is equipped with pressure membrane disc, the inside of mounting hole is equipped with outer sleeve ring, outer sleeve ring is connected with mounting hole by screw thread, the upper end surface of outer sleeve ring is equipped with inner sleeve ring, a plurality of hydraulic channels are arranged in inner sleeve ring, connecting rib is arranged in hydraulic channel, hydraulic channel is equipped with jacking piece, the upper end of jacking piece is in contact with pressure membrane disc, the lower end of inner sleeve ring is equipped with pressure assembly, when the jacking piece in hydraulic channel is lifted up by the deformation of pressure assembly through temperature rise, to pressure membrane disc is opened state, when pressure membrane disc meets sudden high pressure, only needs short distance to move and can fast pressure relief, greatly improves the response speed of pressure relief and action stability.

Description

Technical Field

[0001] This invention relates to the field of relief valves, specifically a pressure relief valve. Background Technology

[0002] Pressure relief valves, as a key component for the safety protection of sealed pressure vessels, are widely used in ultra-high voltage power transmission and transformation facilities, urban power distribution network nodes, and industrial power supply systems. Their safety and reliability directly affect the protection capabilities of core equipment. Arc discharge caused by internal faults in sealed containers can lead to the decomposition of the medium, instantaneously generating a large amount of high-pressure gas and creating an overpressure impact. Without a dedicated relief valve, this can easily cause damage to the container structure, leakage of high-temperature media, and secondary accidents, posing a significant safety hazard. Therefore, pressure relief valves, as the core passive safety device for containers, rapidly open to release pressure when the internal pressure reaches a preset opening value, discharging the high-temperature, high-pressure media, protecting the container structure and internal components. After pressure relief is complete, the valve automatically resets and closes, isolating residual media and preventing secondary combustion and explosion. Currently, due to the limited discharge area of ​​pressure relief valves, multiple valves are required to potentially prevent serious accidents such as container rupture and explosion.

[0003] To address the aforementioned issues, existing technologies offer several solutions. For instance, patent application CN201911153761.X discloses an explosion-proof valve. This application outlines the following solution: a diaphragm disc, a two-stage spring, and a ball-operated locking mechanism are designed within the explosion-proof valve. The diaphragm disc and the primary spring enable precise pressure relief and early warning for conventional overpressure. The diaphragm disc pushes a push rod to unlock the locking mechanism, triggering the secondary spring to fully open the cover, achieving rapid pressure relief with high flow under extreme fault conditions. The two-stage opening pressure can be calibrated in stages, balancing sealing stability and explosion-proof protection capabilities. However, this solution has certain limitations in practical use: the multiple moving parts require extremely high assembly precision and media cleanliness; impurities and deposits can easily cause movement jamming, leading to the secondary mechanism refusing to operate or being falsely triggered. The frictional lag between the series-connected multi-stage action link and the locking mechanism results in a large inherent response delay for secondary pressure relief, failing to meet the explosion-proof requirements of millisecond-level overpressure in container faults. The dynamic response accuracy is poor, and pressure relief lag is likely to occur under extreme conditions. Summary of the Invention

[0004] The purpose of this invention is to provide a pressure relief valve to solve the problem of insufficient pressure relief capacity of pressure relief valves, and at the same time solve the problem of slow response speed of existing technology.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A pressure relief valve includes a valve body with a pressure relief hole on its side and a mounting hole at its lower end. The valve body has an axially penetrating valve cavity that communicates with the pressure relief hole and the mounting hole. An end cap is located at the upper end of the valve cavity, and an adjusting bolt is positioned at the center of the end cap. A spring cover is located at the lower end of the adjusting bolt, and a return spring is housed within the spring cover. A pressure-bearing diaphragm is coaxially positioned at the lower end of the return spring, and the edge of the pressure-bearing diaphragm is sealed to the valve body. An outer ring is located within the mounting hole and is threadedly connected to the mounting hole. An inner ring is provided on the upper end face of the outer ring, and multiple hydraulic channels are provided in the inner ring. Multiple connecting ribs are provided in the hydraulic channels, and the multiple connecting ribs are circumferentially distributed in the hydraulic channels. The height of the connecting ribs is the same as the height of the hydraulic channels. Each of the multiple hydraulic channels is provided with a lifting plate. The upper end of the multiple lifting plates is in contact with the lower end face of the pressure diaphragm. A pressure component is provided at the lower end of the inner ring. The pressure component deforms when heated and acts on the hydraulic channels, causing the lifting plates to rise. The lifting height of the lifting plates is insufficient to open the pressure relief hole of the pressure diaphragm.

[0006] A valve cavity, axially penetrating the valve body and connected to the side pressure relief hole and the lower mounting hole, forms the basic flow channel for pressure transmission and relief. An end cap, adjusting bolt, spring cap, and return spring are sequentially installed at the upper end of the valve cavity. The lower end of the return spring is coaxially connected to a pressure-bearing diaphragm that seals with the valve body. The preload of the return spring can be adjusted by adjusting the adjusting bolt to precisely set the valve opening pressure, ensuring reliable sealing of the valve body under normal conditions. An outer ring is threaded into the mounting hole, and an inner ring is installed on its upper end face. The inner ring has multiple hydraulic channels, with connecting ribs of the same height distributed around the circumference of each channel. This strengthens the structural strength of the hydraulic channels without hindering the flow of the internal medium. A lifting plate, whose upper end contacts the lower end face of the pressure-bearing diaphragm, is installed within the hydraulic channels. A lifting plate is installed at the lower end of the inner ring to facilitate the lifting... After the temperature changes, the pressure component acting on the hydraulic channel causes the lifting plate to rise. The pressure component, due to the temperature change, compresses the space in the hydraulic channel, causing the lifting plate to rise, so that the pressure diaphragm is in a ready-to-open state in advance. In the event of sudden high pressure, only a small pressure change is needed to quickly open the pressure diaphragm to release pressure, which greatly improves the pressure relief response speed. At the same time, the setting that the lifting plate cannot open the pressure diaphragm alone effectively avoids the situation of accidental oil leakage when there is only high temperature without high pressure. It realizes pressure relief triggered by both temperature and pressure, which takes into account both the speed of pressure relief and the safety of use. The threaded connection between the outer ring and the mounting hole facilitates the disassembly and maintenance of the inner ring and supporting components. The synchronous contact of multiple lifting plates also makes the pressure diaphragm more evenly stressed, ensuring the stability of valve operation.

[0007] Preferably, the hydraulic channel is connected to the pressure assembly, which includes a metal deformation plate. The metal deformation plate is annular, and both its outer and inner edges are fixedly connected to the lower end of the inner ring. The middle part of the metal deformation plate is in contact with the hydraulic channel. The metal deformation plate is made of shape memory metal, and its deformation direction is upward. The axial deformation of the metal deformation plate when heated from 25°C to 200°C is 5-10 mm.

[0008] By connecting the hydraulic channel to the pressure assembly, which employs a ring-shaped metal deformation plate structure, the outer and inner edges of the metal deformation plate are fixedly connected to the lower end of the inner ring, with the center in contact with the hydraulic channel. The metal deformation plate is made of shape memory metal and its deformation direction is set upwards. This metal deformation plate can produce a deformation of 5-10 mm when heated from 25℃ to 200℃. The shape memory metal material gives the metal deformation plate a sensitive and stable response to temperature changes, ensuring the accuracy and repeatability of the deformation. The ring structure combined with the edge fixing method ensures that when the metal deformation plate heats up, the limiting effect causes only the center to deform upwards with the preset deformation amount, preventing deformation deviation from affecting the applied force. The design incorporates a metal deformation plate with its center in contact with and connected to the hydraulic channel. This allows the upward deformation of the plate to directly and evenly compress the medium within the hydraulic channel, efficiently transferring the deformation force to the lifting plate. The preset deformation of 5-10mm provides sufficient lifting force to stably raise the lifting plate to a preset height, thereby pushing the pressure diaphragm into a ready-to-open state. This prepares the equipment for rapid pressure relief under high pressure conditions. Furthermore, this structural design allows the pressure component to precisely lift the lifting plate solely through temperature deformation. Combined with the overall setting that the lifting plate's height is insufficient to open the pressure diaphragm, this effectively prevents accidental oil leakage in situations where high temperature is present without high pressure.

[0009] Preferably, a hydraulic cavity is provided between the inner sleeve and the metal deformation plate, the horizontal projection of the hydraulic cavity is annular, the metal deformation plate is installed at the bottom of the hydraulic cavity, and the hydraulic cavity is connected to multiple hydraulic channels.

[0010] By setting a horizontally annular hydraulic cavity between the inner ring and the metal deformation plate, and installing the metal deformation plate at the bottom of the hydraulic cavity, while connecting the hydraulic cavity to multiple hydraulic channels, the structure of the annular hydraulic cavity is adapted to the deformation characteristics of the annular metal deformation plate. This allows the metal deformation plate to generate a uniform extrusion force on the medium inside the cavity when it heats up and deforms upward, avoiding uneven local stress. The connection design between the hydraulic cavity and multiple hydraulic channels can synchronously and smoothly transmit this uniform extrusion force to each hydraulic channel, ensuring that the lifting plates in each hydraulic channel receive consistent lifting power. This achieves synchronous and equal-height lifting of multiple lifting plates, ensuring uniform force on the lower end face of the pressure diaphragm, effectively preventing problems such as uneven wear and jamming of the pressure diaphragm. At the same time, the annular hydraulic cavity can maximize the deformation range of the metal deformation plate, improve the efficiency of pressure transmission, and allow the temperature-triggered deformation force to be transmitted more smoothly and accurately to the lifting plates, providing a reliable hydraulic power transmission guarantee for the pressure diaphragm to be stably in the ready-to-open state.

[0011] Preferably, a limiting platform is provided at the upper end of the hydraulic channel, and a buckle is provided at the lower end of the lifting plate. When the limiting platform and the buckle are engaged, the axial distance between the lower end face of the pressure-bearing diaphragm and the lower end opening edge of the pressure discharge hole is 1-2 mm.

[0012] By setting a limiting platform at the upper end of the hydraulic channel and a corresponding buckle at the lower end of the lifting plate, and ensuring that the lower end face of the pressure-bearing diaphragm is 1-2mm away from the bottom end of the pressure discharge hole when the two are in contact, the maximum lifting height of the lifting plate is strictly controlled by the mechanical cooperation of the limiting platform and the buckle. This prevents excessive lifting that could cause the pressure-bearing diaphragm to accidentally open the pressure discharge hole, thus avoiding accidental oil leakage under high temperature and no high pressure conditions. This stabilizes the pressure relief mode triggered by both temperature and pressure, and the extremely small gap of 1-2mm ensures that the pressure-bearing diaphragm... After the pressure diaphragm is lifted by the lifting plate, it is in a state very close to opening the pressure relief hole. When the equipment experiences a sudden high pressure, the pressure diaphragm only needs to move upward a very short distance to quickly open the pressure relief hole and release pressure, which greatly shortens the pressure relief stroke and effectively improves the valve's millisecond-level response speed to sudden high pressure. At the same time, this limiting structure can keep the maximum lifting height of multiple lifting plates uniform, ensuring that each lifting plate is raised synchronously and at the same height, so that the lower end face of the pressure diaphragm is evenly stressed, avoiding problems such as uneven wear and jamming.

[0013] Preferably, the inner wall of the valve body is provided with a clearance hole, and when the pressure-bearing diaphragm is in contact with the upper end face of the inner sleeve, the lower end face of the clearance hole is flush with the upper end face of the pressure-bearing diaphragm.

[0014] By providing clearance holes on the inner wall of the valve body, and ensuring that the lower end face of the clearance holes is flush with the upper end face of the pressure diaphragm disc when it is in contact with the upper end face of the inner ring under normal operating conditions, the clearance holes are prevented from interfering with the pressure diaphragm disc during normal operation. This ensures the stability and reliability of the sealing fit between the pressure diaphragm disc and the valve body. Furthermore, when the pressure diaphragm disc is lifted by the lifting plate and moves upward under high pressure to open the pressure relief hole, sufficient space is provided for the upward lifting and axial movement of the pressure diaphragm disc. This effectively prevents the pressure diaphragm disc from scraping, contacting, or even getting stuck with the inner wall of the valve body during its upward movement, ensuring smooth and unobstructed lifting and pressure relief actions, and guaranteeing timely pressure relief response.

[0015] Preferably, the lower part of the side wall of the pressure-bearing diaphragm is provided with a guide surface, which is arc-shaped.

[0016] By setting an arc-shaped guide surface on the lower side wall of the pressure diaphragm, this arc-shaped structure transforms the contact between the pressure diaphragm and the inner wall of the valve body into a smooth arc-shaped surface contact during the process of the pressure diaphragm moving upward under the action of the lifting plate and high pressure to open the pressure relief hole, and during the process of the pressure diaphragm moving downward under the action of the return spring after pressure relief. This significantly reduces the frictional resistance and abrasive wear between the two, while also providing precise guidance and correction for the axial movement of the pressure diaphragm, effectively preventing the pressure diaphragm from deviating or jamming during operation. This ensures that its lifting and resetting actions are always smooth and stable, guaranteeing the timeliness of pressure relief response and the reliability of sealing resetting. Furthermore, the design of this arc-shaped guide surface will not cause structural interference to the normal sealing fit between the pressure diaphragm and the valve body, thus stabilizing the basic sealing performance of the valve body and extending the overall service life of the pressure diaphragm.

[0017] Preferably, a weight-reducing groove is provided at the center of the pressure-bearing membrane tray, and the pressure-bearing membrane tray is made of stainless steel.

[0018] By using stainless steel to construct the pressure-bearing diaphragm and incorporating a weight-reducing groove at its center, the diaphragm is made of stainless steel. Stainless steel possesses excellent high-temperature resistance, oil corrosion resistance, and deformation resistance, making it suitable for high-temperature, high-pressure oil and gas impact conditions during transformer faults. This ensures the reliability of the sealing fit between the pressure-bearing diaphragm and the valve body, as well as structural strength, meeting the requirements for long-term contact with insulating oil. The central weight-reducing groove effectively lowers the overall weight of the diaphragm without compromising its core pressure-bearing capacity and sealing performance. This reduces the resistance to the diaphragm's upward lifting under high pressure, allowing for faster pressure relief and improving the sensitivity of the pressure relief action. It also reduces the load on the return spring, ensuring the smoothness and stability of the diaphragm's reset action after pressure relief. The combination of these two aspects balances the diaphragm's adaptability to various operating conditions, structural reliability, and operational flexibility.

[0019] Preferably, a copper ring is provided at the lower middle part of the metal deformation sheet, and a plurality of deformation grooves are provided on the ring body of the copper ring along the circumferential direction, and the thickness of the copper ring is 1 to 2 mm.

[0020] By setting a copper ring with a deformation groove and a thickness of 1-2mm at the lower middle part of the metal deformation plate, the excellent thermal conductivity of copper can quickly transfer the high temperature inside the equipment to the metal deformation plate, improving the sensitivity of the metal deformation plate to temperature changes and allowing it to deform upwards more promptly. The thin design of 1-2mm ensures that the copper ring has a certain structural support, which can help enhance the structural strength of the middle part of the metal deformation plate, avoid fatigue damage caused by repeated heating and deformation, and extend its service life. At the same time, the deformation groove on the copper ring allows the copper ring to adapt to the upward deformation of the metal deformation plate, avoiding deformation interference between the copper ring and the metal deformation plate, which would affect the normal deformation of the metal deformation plate and the transmission of deformation force. This ensures that the deformation force of the metal deformation plate can be stably and efficiently transmitted to the hydraulic channel, providing a reliable guarantee for the stable lifting of the lifting plate.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The design utilizes the temperature deformation of the pressure component to raise the lifting plate to the ready-to-open state. Combined with the lifting height limit of the lifting plate and the dual temperature and pressure triggering logic of the pressure-bearing diaphragm plate and the pressure discharge hole with a spacing of 1-2mm, and the interconnected structure of the annular hydraulic chamber and multiple hydraulic channels, it avoids the problem of accidental oil leakage under high temperature without high pressure conditions. It realizes the linkage of temperature pre-triggered and pressure main triggered pressure relief. The extremely small spacing of 1-2mm allows the pressure-bearing diaphragm plate to quickly relieve pressure with only a short distance when encountering sudden high pressure. It meets the explosion-proof requirements of millisecond-level overpressure in transformer faults. The annular hydraulic chamber can also make multiple lifting plates rise synchronously at the same height, so that the pressure-bearing diaphragm plate is subjected to uniform force, effectively preventing jamming and uneven wear, and greatly improving the pressure relief response speed and operation stability.

[0022] 2. The pressure setting structure, which adjusts the preload of the return spring by adjusting the bolts, is combined with a stainless steel pressure-bearing diaphragm disc with a weight-reducing groove, an arc-shaped guide surface, and a clearance hole for motion adaptation. This, along with the automatic reset function of the return spring, avoids the problem of the pressure-bearing diaphragm disc rubbing against the inner wall of the valve body during operation, achieving precise setting of the valve opening pressure. The stainless steel material is suitable for transformer high-temperature, high-pressure oil and gas impact conditions. The weight-reducing groove lowers the weight of the diaphragm disc and improves the sensitivity of the pressure relief action. The guide surface and clearance hole ensure smooth and unobstructed lifting and reset of the pressure-bearing diaphragm disc. After pressure relief, the return spring can drive the diaphragm disc to quickly reset and close, isolating residual oil and gas inside to prevent secondary combustion and explosion. Simultaneously, the threaded connection between the outer ring and the mounting hole enables modular assembly, significantly improving the valve's adaptability to operating conditions and the convenience of disassembly and maintenance.

[0023] 3. By using a ring-shaped metal deformation plate made of shape memory metal in combination with a 1-2mm thick copper ring with deformation groove, and a circumferentially distributed equal-height connecting rib structure in the hydraulic channel, problems such as deformation interference of the metal deformation plate, overpressure deformation of the hydraulic channel, and uneven pressure transmission are avoided. The excellent thermal conductivity of the copper ring improves the sensitivity of the metal deformation plate to temperature changes. The deformation groove is adapted to the upward deformation of the metal deformation plate. The shape memory metal ensures the accuracy and repeatability of deformation. The connecting ribs strengthen the structural strength of the hydraulic channel without hindering the flow of the medium, ensuring that the deformation force of the pressure component is efficiently and smoothly transmitted to the lifting plate. The coordinated operation of each component extends the overall service life of the valve and improves the reliability of pressure relief power transmission, thereby ensuring the safe and stable operation of the oil-immersed power transformer. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the pressure relief valve of the present invention; Figure 2 This is a front view of the pressure component of the present invention when it is not in use; Figure 3 for Figure 2 A sectional view of AA; Figure 4 for Figure 3 Enlarged view of point B in the middle; Figure 5 This is a front view of the pressure component of the present invention in operation; Figure 6 for Figure 5 A cross-sectional view of CC; Figure 7 for Figure 6 Enlarged view at point D; Figure 8 This is a schematic diagram of the inner ring structure.

[0025] In the diagram: 1. Valve body; 101. Pressure relief hole; 102. Mounting hole; 103. Valve cavity; 104. Adjusting bolt; 105. Clearance hole; 106. End cap; 107. Screw; 108. Star handle; 2. Spring cover; 201. Return spring; 3. Pressure diaphragm; 301. Guide surface; 302. Weight reduction groove; 4. Outer ring; 5. Inner ring; 501. Hydraulic channel; 502. Connecting rib; 503. Lifting plate; 504. Limiting platform; 505. Buckle; 6. Metal deformation plate; 7. Hydraulic cavity; 8. Copper ring; 801. Deformation groove. Detailed Implementation

[0026] Please see Figures 1 to 8 This invention provides a pressure relief valve, the technical solution of which is as follows: For details, please refer to Figures 1 to 8A pressure relief valve includes a valve body 1, a pressure relief hole 101 on the side of the valve body 1, a mounting hole 102 at the lower end of the valve body 1, and an axially penetrating valve cavity 103 communicating with the pressure relief hole 101 and the mounting hole 102. An end cap 106 is provided at the upper end of the valve cavity 103, and the end cap 106 is fixedly connected to the valve body 1 by screws 107. An adjusting bolt 104 is provided at the center of the end cap 106, a star-shaped handle 108 is installed at the upper end of the adjusting bolt 104, and a spring cover 2 is provided at the lower end of the adjusting bolt 104. A return spring 201 is provided inside the spring cover 2, and a pressure-bearing diaphragm 3 is coaxially provided at the lower end of the return spring 201. The edge of the pressure-bearing diaphragm 3 is sealed to the valve body 1, and the lower part of the side wall of the pressure-bearing diaphragm 3... A guide surface 301 is provided, which is arc-shaped. A weight-reducing groove 302 is provided at the center of the pressure diaphragm 3. The pressure diaphragm 3 is made of stainless steel. An outer ring 4 is provided in the mounting hole 102, and the outer ring 4 is threaded to the mounting hole 102. An inner ring 5 is provided on the upper end face of the outer ring 4. An clearance hole 105 is provided on the inner side wall of the valve body 1. When the pressure diaphragm 3 is in contact with the upper end face of the inner ring 5, the lower end face of the clearance hole 105 is flush with the upper end face of the pressure diaphragm 3. Multiple hydraulic channels 501 are provided in the inner ring 5, and multiple connecting ribs 502 are provided in the hydraulic channels 501. The multiple connecting ribs 502 are circumferentially distributed in the hydraulic channels 501, and the height of the connecting ribs 502 is the same as the height of the hydraulic channels 501. Each hydraulic channel 501 is equipped with a lifting plate 503. The upper ends of the lifting plates 503 are in contact with the lower end face of the pressure diaphragm 3. A limiting platform 504 is provided at the upper end of the hydraulic channel 501, and a buckle 505 is provided at the lower end of the lifting plate 503. When the limiting platform 504 and the buckle 505 are in contact, the axial distance between the lower end face of the pressure diaphragm 3 and the lower end opening edge of the pressure discharge hole 101 is 2mm. A pressure assembly is provided at the lower end of the inner ring 5. The hydraulic channel 501 is connected to the pressure assembly. The pressure assembly includes a metal deformation plate 6. The metal deformation plate 6 is annular, and both the outer and inner edges of the metal deformation plate 6 are fixedly connected to the lower end of the inner ring 5. The middle part of the metal deformation plate 6 is in contact with the hydraulic channel 501. A copper ring 8 is provided at the end. Multiple deformation grooves 801 are opened on the ring body of the copper ring 8 along the circumference. The thickness of the copper ring 8 is 1mm. A hydraulic cavity 7 is provided between the inner ring 5 and the metal deformation plate 6. The horizontal projection of the hydraulic cavity 7 is annular. The metal deformation plate 6 is installed at the bottom of the hydraulic cavity 7. The hydraulic cavity 7 is connected to multiple hydraulic channels 501. The metal deformation plate 6 is made of shape memory metal. The deformation direction of the metal deformation plate 6 is upward. When the metal deformation plate 6 is heated from 25℃ to 200℃, the axial deformation is 10mm. The pressure component deforms due to heating and acts on the hydraulic channel 501, causing the lifting plate 503 to rise. The lifting height of the lifting plate 503 is insufficient to open the pressure relief hole 101 of the pressure diaphragm 3.

[0027] Working principle: Please refer to Figures 1 to 8Under normal operating conditions of an oil-immersed power transformer, the pressure relief valve is fixed to the transformer tank cavity through the mounting hole 102 at the lower end of the valve body 1. The valve cavity 103, which runs axially through the valve body 1, is connected to the tank cavity and the side pressure relief hole 101. The end cover 106 at the upper end of the valve cavity 103 is fixed by screws 107. The preload of the return spring 201 inside the spring cover 2 is adjusted by rotating the star handle 108 at the upper end of the adjusting bolt 104. A pressure-bearing diaphragm 3 is coaxially arranged at the lower end of the return spring 201, and its edge is sealed to the valve body 1. The lower end face of the pressure-bearing diaphragm 3 is tightly fitted with the upper end face of the inner sleeve 5. The lower end face of the clearance hole 105 on the inner side wall of the valve body 1 is flush with the upper end face of the pressure-bearing diaphragm 3, without structural interference. Mounting hole 102 The outer ring 4 with internal thread connection and the inner ring 5 set on the upper end face are kept fixed. The lifting plate 503 in the hydraulic channel 501 in the inner ring 5 is in the initial low position. The upper end of the lifting plate 503 is in contact with the lower end face of the pressure diaphragm 3. The connecting ribs 502 distributed around the circumference in the hydraulic channel 501 ensure the structural strength of the channel throughout. The pressure component at the lower end of the inner ring 5 is in the initial state. At room temperature of 25℃, the annular metal deformation plate 6 made of shape memory metal does not deform upward. The volume of the annular hydraulic cavity 7 between the inner ring 5 and the metal deformation plate 6 is stable. There is no pressure fluctuation in the medium in the cavity. The 1mm thick copper ring 8 at the lower end of the middle of the metal deformation plate 6 is not triggered by heat conduction. The entire valve is in a reliable sealed standby state, isolating the insulating oil and oil gas in the transformer oil tank and ensuring the normal operation of the equipment.

[0028] When the transformer experiences abnormal operating conditions and the internal temperature of the oil tank continues to rise, the copper ring 8, with its excellent thermal conductivity, quickly transfers the high temperature inside the oil tank to the metal deformation plate 6. As the temperature of the metal deformation plate 6 rises from 25℃ to 200℃, it undergoes a 10mm directional upward deformation. The outer and inner edges of the metal deformation plate 6 are fixed to the lower end of the inner ring 5, with only the middle part deforming upward and compressing the internal space of the annular hydraulic cavity 7. The hydraulic cavity 7 is fully connected to multiple hydraulic channels 501. The deformation and compressive force is synchronously and evenly transmitted to each hydraulic channel 501 through the medium inside the cavity, pushing the hydraulic channels 501. The lifting plate 503 inside 1 is raised upward. When the buckle 505 at the lower end of the lifting plate 503 is in contact with the limiting platform 504 at the upper end of the hydraulic channel 501, a mechanical limit is formed, which strictly controls the maximum lifting height of the lifting plate 503. At this time, the pressure diaphragm 3 is raised synchronously by the lifting plate 503. The axial distance between its lower end face and the lower end hole edge of the pressure discharge hole 101 is maintained at 2mm. The lifting height is insufficient to open the pressure discharge hole 101 of the pressure diaphragm 3, so as to avoid accidental oil leakage under the condition of high temperature without high pressure. The pressure diaphragm 3 is in a state of being very close to opening and ready to be triggered, thus completing the temperature pre-trigger preparation.

[0029] When a fault occurs inside the transformer and an arc discharge causes a momentary overpressure impact, the high-pressure oil and gas in the tank enters the valve chamber 103 through the mounting hole 102 and directly acts on the pressure-bearing diaphragm 3, which is in the waiting-to-open state. The pressure-bearing diaphragm 3 only needs to move upward by a very short stroke of 2mm to quickly open the connecting channel of the pressure relief hole 101, realizing large-flow pressure relief. During the upward movement of the pressure-bearing diaphragm 3, the arc-shaped guide surface 301 on the lower part of its side wall forms a smooth guide, which greatly reduces the frictional resistance with the inner wall of the valve body 1 and avoids deviation and jamming. The clearance hole 105 on the inner side wall of the valve body 1 provides sufficient space for the axial movement of the pressure-bearing diaphragm 3, ensuring that the lifting action is smooth and unobstructed. The weight-reducing groove 302 in the center of the pressure-bearing diaphragm 3 effectively reduces its own weight, further improving the response sensitivity of the pressure relief action, matching the explosion-proof requirements of millisecond-level overpressure of transformer faults. High-temperature and high-pressure oil and gas are quickly discharged through the valve chamber 103 and the pressure relief hole 101, avoiding overpressure damage to the tank cavity and oil and gas leakage and explosion.

[0030] After the pressure relief valve completes the pressure relief operation and the internal pressure and temperature of the transformer tank return to normal, the return spring 201 releases the compressed elastic return force, pushing the pressure-bearing diaphragm 3 downward to slide smoothly back to its original position along the axial direction. The edge of the pressure-bearing diaphragm 3 and the valve body 1 re-form a sealing fit, isolating residual oil and gas inside the tank and preventing secondary combustion and explosion. As the internal temperature of the tank decreases, the metal deformation plate 6 returns to its initial flat state due to the shape memory metal properties, the volume of the annular hydraulic chamber 7 returns to normal, the pressure of the medium inside the chamber drops, and the lifting plate 503 slides down synchronously with the return of the medium and its own weight. Upon resetting, the latch 505 disengages from the limit table 504 and returns to its initial low position within the hydraulic channel 501. As the temperature decreases, the copper ring 8 at the lower end of the metal deformation plate 6 returns to its initial state. The deformation groove 801 on the copper ring 8 adapts to the deformation and reset of the metal deformation plate 6 throughout the process. The pressure diaphragm 3 re-fits with the upper end face of the inner ring 5. All components, including the adjusting bolt 104, spring cover 2, reset spring 201, hydraulic channel 501, and pressure assembly, return to their initial sealed standby state, ready to respond to the next temperature and pressure triggering action, ensuring the long-term safe and stable operation of the transformer.

[0031] The specific embodiment of the present invention has been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the embodiments described above. For those skilled in the art, various changes, modifications, substitutions, and variations made to these embodiments without departing from the principles and ideas of the present invention should still fall within the protection scope of the present invention.

Claims

1. A pressure relief valve, comprising a valve body (1), wherein a pressure relief hole (101) is provided on the side of the valve body (1), and a mounting hole (102) is provided at the lower end of the valve body (1). The valve body (1) has an axially penetrating valve cavity (103), the valve cavity (103) communicating with the pressure relief hole (101) and the mounting hole (102). An end cap (106) is provided at the upper end of the valve cavity (103), an adjusting bolt (104) is provided at the center of the end cap (106), a spring cover (2) is provided at the lower end of the adjusting bolt (104), a return spring (201) is provided inside the spring cover (2), and a pressure-bearing diaphragm (3) is coaxially provided at the lower end of the return spring (201). The edge of the pressure-bearing diaphragm (3) is sealed to the valve body (1). An outer ring (4) is provided inside the mounting hole (102), and the outer ring (4) is threadedly connected to the mounting hole (102). An inner ring (5) is provided on the upper end face of the outer ring (4). A plurality of hydraulic channels (501) are provided in the inner ring (5), and a plurality of connecting ribs (502) are provided in the hydraulic channels (501). The plurality of connecting ribs (502) are circumferentially distributed in the hydraulic channels (501), and the height of the connecting ribs (502) is perpendicular to the height of the hydraulic channels (501). 501) The height is consistent, and each of the multiple hydraulic channels (501) is provided with a lifting plate (503). The upper end of the multiple lifting plates (503) is in contact with the lower end face of the pressure diaphragm (3). The lower end of the inner ring (5) is provided with a pressure component. The pressure component deforms by heating and acts on the hydraulic channel (501) to lift the lifting plate (503) upward. The lifting height of the lifting plate (503) is not enough to make the pressure diaphragm (3) open the pressure relief hole (101).

2. A pressure relief valve according to claim 1, characterized in that, The hydraulic channel (501) is connected to the pressure assembly, which includes a metal deformation plate (6). The metal deformation plate (6) is annular, and the outer and inner edges of the metal deformation plate (6) are fixedly connected to the lower end of the inner ring (5). The middle part of the metal deformation plate (6) is in contact with the hydraulic channel (501). The metal deformation plate (6) is made of shape memory metal, and the deformation direction of the metal deformation plate (6) is upward. The axial deformation of the metal deformation plate (6) when heated from 25°C to 200°C is 5-10 mm.

3. A pressure relief valve according to claim 2, characterized in that, A hydraulic cavity (7) is provided between the inner sleeve (5) and the metal deformation plate (6). The horizontal projection of the hydraulic cavity (7) is annular. The metal deformation plate (6) is installed at the bottom of the hydraulic cavity (7). The hydraulic cavity (7) is connected to multiple hydraulic channels (501).

4. A pressure relief valve according to claim 1, characterized in that, The upper end of the hydraulic channel (501) is provided with a limiting platform (504), and the lower end of the lifting plate (503) is provided with a buckle (505). When the limiting platform (504) and the buckle (505) are in contact, the axial distance between the lower end face of the pressure bearing diaphragm (3) and the lower end opening edge of the pressure discharge hole (101) is 1-2 mm.

5. A pressure relief valve according to claim 4, characterized in that, The valve body (1) has an clearance hole (105) on its inner side wall. When the pressure diaphragm (3) is in contact with the upper end face of the inner sleeve (5), the lower end face of the clearance hole (105) is flush with the upper end face of the pressure diaphragm (3).

6. A pressure relief valve according to claim 5, characterized in that, The lower part of the side wall of the pressure-bearing diaphragm (3) is provided with a guide surface (301), which is arc-shaped.

7. A pressure relief valve according to claim 1, characterized in that, The pressure-bearing membrane plate (3) is provided with a weight-reducing groove (302) at the center, and the pressure-bearing membrane plate (3) is made of stainless steel.

8. A pressure relief valve according to claim 2, characterized in that, A copper ring (8) is provided at the lower middle part of the metal deformation sheet (6). Multiple deformation grooves (801) are provided on the ring body of the copper ring (8) and distributed in the circumferential direction. The thickness of the copper ring (8) is 1-2 mm.

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