A pressure relief valve

Abstract

This application relates to a pressure protection device for transformers, specifically a pressure relief valve, comprising a housing and a valve assembly. The valve assembly integrates the pressure cap and support plate onto a connector, which in turn interlocks with a positioning post on the valve plate. This allows the entire valve assembly to be easily removed by simply removing the fixing screws connecting the pressure cap and the housing, significantly reducing maintenance time. Furthermore, the valve assembly design ensures that the spring preload is precisely set at the factory, eliminating the need for readjustment after maintenance. Single-person operation is possible, greatly lowering the maintenance threshold. Additionally, the positioning post ensures precise alignment of the diaphragm, support ring, and valve plate, and, combined with the downwardly recessed diaphragm design, achieves a reliable sealing effect.

Description

Technical Field

[0001] This application relates to a pressure protection device for a transformer, specifically a pressure relief valve. Background Technology

[0002] Pressure relief valves are critical safety protection devices for oil-immersed electrical equipment and require regular maintenance to ensure their reliability. However, traditional pressure relief valves typically consist of multiple independent parts such as valve seat, valve disc, spring, adjusting screw, and valve cover. Maintenance requires disassembling bolts and removing individual parts one by one. After replacing the rupture diaphragm, reassembly and adjustment of the spring preload are also necessary. The entire process is time-consuming, complex, and prone to errors.

[0003] To address the cumbersome process of valve cover disassembly and assembly, some improvements have emerged in existing technologies. For example, Chinese patent application CN219866525U discloses a transformer pressure relief valve that uses a snap-fit ​​mechanism to quickly open the valve cover without removing multiple bolts. However, this structure only shortens the time of "exposing the interior." After accessing the internal core components, diaphragm replacement still requires disassembling the pressure ring with tools, and the valve disc, valve stem, and spring assembly remain in separate parts, requiring individual disassembly, realignment, and adjustment of the spring preload. Therefore, it fails to achieve complete disassembly and assembly of the internal core components, and the improvement in maintenance efficiency remains limited.

[0004] It is evident that, regardless of whether the existing pressure relief valve has a traditional bolt-fixed structure or an improved structure with a quick-release cover, its internal core components such as valve discs, springs, and diaphragms are all assembled in a decentralized manner. This results in a tedious process of "disassembling layer by layer, disassembling and reassembling one by one, and re-adjusting" during on-site maintenance, leading to long maintenance time, high tool dependence, and poor operational consistency. Summary of the Invention

[0005] The purpose of this application is to provide a pressure relief valve that integrates core components such as springs and diaphragms inside the housing into one unit, thereby facilitating the disassembly of the integrated structure, shortening disassembly time, and improving maintenance efficiency and reliability.

[0006] To achieve the above objectives, this application provides a pressure relief valve, comprising: a housing, wherein the interior of the housing has an installation space, and the bottom of the housing has an opening; A valve assembly, which is located within the installation space, includes: a connector (3) and a pressure cap, a spring assembly, a bearing plate, a support ring, a diaphragm and a valve disc arranged sequentially from top to bottom; The pressure cap is screwed to the outer shell. The bottom of the connector has a slot. The connector passes through the pressure cap and the support plate in sequence and extends downward to the support plate. The connector is detachably connected to the support plate. The connector can slide relative to the pressure cap in the vertical direction. The spring assembly is located between the pressure cap and the support plate. Both the valve plate and the support ring have holes for the diaphragm to pass through. The valve plate has a positioning post that passes through the diaphragm and the support ring and is inserted into the slot. The valve plate abuts against the bottom of the outer shell. The diaphragm is recessed downward and partially protrudes from the bottom opening of the outer shell to form a seal at the bottom of the outer shell.

[0007] As a preferred technical solution, the pressure cap has a first connecting hole, the support plate has a second connecting hole, the connector passes through the first connecting hole and the second connecting hole and is inserted into the positioning post, and the connector is slidably connected to the first connecting hole, and is detachably connected to the support plate at the second connecting hole; the spring assembly is closer to the center of the support plate than the connector.

[0008] As a preferred technical solution, the diameter of the first connecting hole is d1, and the diameter of the connector is d2, wherein 1mm≤d1-d2≤2mm.

[0009] As a preferred technical solution, the connector includes a guide rod and a transmission rod. The upper end of the guide rod passes through the first connecting hole and is slidably connected to the pressure cap. The lower end of the guide rod passes through the second connecting hole and is screwed to the transmission rod. The bearing plate abuts against the upper end face of the transmission rod. The slot is opened at the bottom of the transmission rod, and the transmission rod is inserted into the positioning post.

[0010] As a preferred technical solution, it further includes: a fastener, which passes through the support ring and abuts against the diaphragm.

[0011] As a preferred technical solution, the spring assembly includes: a first spring and a second spring, wherein the diameter of the second spring is larger than the diameter of the first spring, the first spring is located at the center of the bearing plate, and the second spring is sleeved on the outer periphery of the first spring.

[0012] As a preferred technical solution, the load-bearing plate is provided with a first protrusion and a second protrusion arranged concentrically along the direction close to the pressure cover. The first protrusion is located at the center of the load-bearing plate, and the diameter of the first protrusion is smaller than that of the second protrusion. The second protrusion is located on the outer periphery of the first protrusion. The first spring is located between the first protrusion and the second protrusion, and the second spring is located on the outer side of the second protrusion.

[0013] As a preferred technical solution, the pressure cap is provided with a first groove and a second groove that are interconnected along the direction close to the bearing plate. The second groove is located on the outer periphery of the first groove, the first spring is located in the first groove, and the second spring is located in the second groove.

[0014] As a preferred technical solution, the housing includes: a shell and a top cover and a base respectively screwed to the upper and lower ends of the shell, the opening is formed on the base, the valve disc abuts against the base, the diaphragm portion protrudes from the base to form a seal at the bottom of the base, and the top cover, the shell and the inner peripheral wall of the base together define the installation space.

[0015] As a preferred technical solution, the pressure relief valve further includes: an indicator rod, a third connecting hole at the center of the pressure cap, a warning port at the center of the top cover, the indicator rod passing through the warning port, the third connecting hole, and the spring assembly in sequence and connected to the bearing plate, and the indicator rod can slide relative to the pressure cap and the top cover in the up-down direction.

[0016] As a preferred technical solution, the marker pole is bonded to the load-bearing plate with an adhesive.

[0017] The pressure relief valve provided by the above technical solution has the following advantages compared with the prior art: The valve assembly of this application integrates the gland and the bearing plate onto the connector, and the connector forms an insertion connection with the positioning pin on the valve plate. This allows the entire valve assembly to be pulled out at once simply by removing the fixing screws connecting the gland and the housing, significantly shortening maintenance time. Simultaneously, the valve assembly design ensures that the spring preload is precisely set at the factory, eliminating the need for readjustment after maintenance. Single-person operation is possible, greatly reducing the maintenance threshold. Furthermore, the positioning pin passing sequentially through the diaphragm and support ring ensures precise alignment of the diaphragm, support ring, and valve plate. Combined with the downwardly recessed diaphragm design, a reliable sealing effect is achieved.

[0018] Furthermore, the separate design of the guide rod and the transmission rod not only ensures the smoothness of the sliding guidance but also realizes the effective transmission of force, thereby improving the reliability of the action.

[0019] Furthermore, the gap between the connector and the first connecting hole is controlled within the range of 1-2mm, which ensures both the flexibility of sliding and avoids excessive looseness that could affect the sealing performance.

[0020] Furthermore, fasteners are installed on the support ring to additionally secure the diaphragm, preventing displacement or damage under high pressure and improving its service life.

[0021] Furthermore, this application employs a double-spring structure with a large and a small spring interlocking, which ensures sufficient opening pressure and provides good recovery performance, resulting in more stable and reliable operation. Limiting structures are also provided on the bottom surface of the pressure cap and the top surface of the support plate to ensure that the springs do not shift during compression and recovery deformation, further ensuring the reliability of spring operation.

[0022] Furthermore, the indicator pole design provides clear visual indications after valve operation, making it easier for maintenance personnel to promptly identify and handle faults. Attached Figure Description

[0023] The present application will be further described in detail below with reference to the accompanying drawings and preferred embodiments. However, those skilled in the art will appreciate that these drawings are drawn only for the purpose of explaining the preferred embodiments and therefore should not be construed as limiting the scope of the present application. Furthermore, unless specifically indicated, the drawings are intended only to conceptually represent the composition or structure of the described objects and may contain exaggerated representations, and the drawings are not necessarily drawn to scale.

[0024] Figure 1 This is a schematic diagram of the pressure relief valve in this application; Figure 2 This is a top view of the pressure relief valve of this application; Figure 3 This is a schematic diagram of the pressure relief valve of this application after the housing has been removed; Figure 4 This is a cross-sectional view of the interior of the pressure relief valve in this application; Figure 5 For this application Figure 4 Enlarged view of point A in the middle; Figure 6 This is another cross-sectional view of the interior of the pressure relief valve in this application; Figure 7 This is a cross-sectional view of the connector in this application; Figure 8 This is a schematic diagram of the cap after it has been flipped over; Figure 9 This is a structural schematic diagram of the load-bearing plate in this application; Figure 10 This is a schematic diagram of the support ring structure of this application; The components are as follows: 1. Outer shell; 11. Housing; 12. Top cover; 121. Warning port; 13. Base; 2. Valve assembly; 21. Pressure cap; 211. First connecting hole; 212. First groove; 213. Second groove; 214. Third connecting hole; 22. Spring assembly; 221. First spring; 222. Second spring; 23. Support plate; 231. Second connecting hole; 232. First protrusion; 233. Second protrusion; 24. Support ring; 241. Second positioning hole; 242. Fixing hole; 25. Diaphragm; 251. First positioning hole; 26. Valve disc; 261. Positioning post; 3. Connector; 31. Guide rod; 32. Transmission rod; 321. Slot; 4. Fastener; 5. Marking rod; 6. Fixing screw. Detailed Implementation

[0025] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0026] In the description of this application, it should be understood that the terms "front," "rear," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, in the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0027] Please see Figure 1 , 3 A pressure relief valve provided in this application embodiment includes: a housing 1 and a valve assembly 2; The interior of the outer casing 1 has an installation space (not shown in the attached drawings), and the bottom of the outer casing 1 has an opening; Valve assembly 2 is disposed within the installation space. Valve assembly 2 includes: a connector 3 and, from top to bottom, a pressure cap 21, a spring assembly 22, a support plate 23, a support ring 24, a diaphragm 25, and a valve disc 26. The pressure cap 21 is screwed to the outer shell 1. The pressure cap 21 has a first connection hole 211. The support plate 23 has a second connection hole 231. The connector 3 has a slot 321 at its bottom and passes through the first connection hole 211 and the second connection hole 231 in sequence, extending downwards from the support plate 23. The connector 3 is detachably connected to the support plate 23. The connector 3 is detachable from the pressure cap 21. Sliding in the up-down direction, the spring assembly 22 is located between the pressure cover 21 and the support plate 23. Both the valve plate 26 and the support ring 24 have holes for the diaphragm 25 to pass through. The valve plate 26 is provided with a positioning post 261. The diaphragm 25 has a first positioning hole 251 and the support ring 24 has a second positioning hole 241. The positioning post 261 passes through the first positioning hole 251 and the second positioning hole 241 in sequence and is inserted into the slot 321. The valve plate 26 abuts against the bottom of the outer shell 1. The diaphragm 25 is recessed downward and partially protrudes from the bottom opening of the outer shell 1 to form a seal at the bottom of the outer shell 1.

[0028] In this embodiment, the pressure cap 21, the support plate 23, the support ring 24, the diaphragm 25, and the valve disc 26 are connected in series to form an integral module via the connector 3. The pressure cap 21 serves as the top fixing point of the valve assembly 2 and is detachably connected to the outer shell 1. The connector 3 is connected to the positioning post 261 on the valve disc 26 via a plug-in method, enabling quick connection and separation of the valve disc 26 from the upper structure. The spring assembly 22 is pre-installed between the pressure cap 21 and the support plate 23, and its compression is determined by the distance between the two. In actual operation, the oil tank is connected to the bottom of the outer casing 1. When the pressure inside the oil tank rises sharply, it impacts the diaphragm 25 at the bottom of the outer casing 1. Under the impact force, the diaphragm 25 drives the support ring 24 and valve disc 26 to move upward axially. Simultaneously, under the connection of the connector 3, the bearing plate 23 and the pressure cap 21 move upward synchronously, and the spring assembly 22 is compressed. At this time, a gap appears between the valve disc 26 and the bottom of the outer casing 1, and the oil in the oil tank enters the outer casing 1 through this gap to reduce the pressure inside the oil tank. After the pressure inside the oil tank decreases, the elastic reset action of the spring assembly 22 drives the entire valve assembly 2 to reset, and the valve disc 26 re-fits the bottom of the outer casing 1 to form a seal. When the oil tank pressure is too high and the diaphragm 25 is damaged and requires maintenance, simply remove the fixing screw 6 between the pressure cap 21 and the outer casing 1, and the entire valve assembly 2 can be pulled out axially from the installation space of the outer casing 1 in one go. After extraction, simply separate the connector 3 from the positioning post 261 to easily replace the diaphragm 25. This structure integrates the core components inside the outer casing 1 into a module, enabling maintenance modes of overall extraction and partial replacement. On-site maintenance time is significantly shortened compared to traditional pressure relief valves, and there is no need to readjust the spring preload, greatly improving maintenance efficiency and ease of operation.

[0029] Please see Figure 7 In some embodiments, the connector 3 includes a guide rod 31 and a transmission rod 32. The upper end of the guide rod 31 passes through the first connecting hole 211 and is slidably connected to the pressure cap 21. The lower end of the guide rod 31 passes through the second connecting hole 231 and is screwed to the transmission rod 32. The bearing plate 23 abuts against the upper end face of the transmission rod 32. The slot 321 is opened at the bottom of the transmission rod 32. The transmission rod 32 is inserted into the positioning post 261.

[0030] In this embodiment, by configuring the connector 3 as a separate guide rod 31 and transmission rod 32, not only is processing and assembly easier, but the functional division is also optimized. The guide rod 31 primarily handles the sliding fit with the pressure cap 21, providing precise axial guidance; the transmission rod 32 is used for the detachable connection with the support plate 23 and the insertion into the positioning post 261 on the valve plate 26. The guide rod 31 and transmission rod 32 are connected by threads, making the entire force transmission path clear and more flexible when different specifications of the transmission rod 32 need to be replaced to adapt to different valve plates 26, thus enhancing the maintainability and adaptability of the structure.

[0031] In some embodiments, the diameter of the first connecting hole 211 is d1, and the diameter of the connector 3 is d2, wherein 1mm ≤ d1 - d2 ≤ 2mm. This embodiment sets the diameter difference between the connector 3 and the first connecting hole 211 on the pressure cap 21 between 1mm and 2mm. This ensures that the connector 3 can slide freely and smoothly up and down within the first connecting hole 211 of the pressure cap 21, preventing jamming due to excessively small gaps, while also ensuring guiding accuracy and limiting radial wobbling of the connector 3. Furthermore, this gap range is an optimal value derived by the inventors after comprehensively considering machining tolerances, thermal expansion, and actuation sensitivity. This effectively ensures that the valve disc 26 and the bearing disc 23 can move stably along the axis during the opening and closing of the pressure relief valve, avoiding sealing failure or uneven spring force due to misalignment.

[0032] To prevent gaps from forming between the diaphragm 25 and the valve disc 26 and support ring 24 when the diaphragm 25 moves under high pressure, thus negatively impacting the sealing performance, some embodiments further include a fastener 4. The support ring 24 also has a fixing hole 242, which is spaced apart from the second positioning hole 241. The fastener 4 passes through the fixing hole 242 and abuts against the diaphragm 25. (See also...) Figure 6 , 10 In this embodiment, by providing fixing holes 242 on the support ring 24 and using fasteners 4 to pre-fix the diaphragm 25 to the support ring 24, during the assembly of the valve assembly 2, the diaphragm 25 is first positioned by the positioning pin 261, and then the fasteners 4 are used to temporarily fix the diaphragm 25 to the support ring 24. This prevents the diaphragm 25 from rotating or shifting during the subsequent installation of the connector 3. This arrangement makes the assembly process of the entire valve assembly 2 more stable and reliable, avoiding the problem that the positioning pin 261 cannot be accurately inserted into the slot 321 due to the displacement of the diaphragm 25, thus improving assembly efficiency. At the same time, it can increase the reliability of the connection between the diaphragm 25, the valve disc 26, and the support ring 24, avoiding gaps between the three under high pressure impact, which would affect the sealing performance of the pressure relief valve. When it is necessary to remove the diaphragm, simply pull out the connector 3 and remove the fasteners 4 to remove the diaphragm, which is simple and quick.

[0033] To improve the reliability of the pressure relief valve, in some embodiments, the spring assembly 22 includes a first spring 221 and a second spring 222, wherein the diameter of the second spring 222 is larger than the diameter of the first spring 221, the first spring 221 is located at the center of the bearing plate 23, and the second spring 222 is sleeved on the outer periphery of the first spring 221. See also... Figure 4 , 6 This embodiment employs a combination of large and small springs in series to form a spring system with two levels of stiffness. In the initial stage of pressure relief valve opening, the first spring 221 is compressed first, providing softer stiffness and enabling the valve to respond quickly. As the valve disc 26 opens further, the second spring 222 begins to work, providing greater stiffness, limiting the maximum lift of the valve disc 26, and storing sufficient reseating energy. This dual-spring structure makes the opening and reseating characteristic curves of the pressure relief valve smoother and more controllable, avoiding the problems of inaccurate opening pressure or excessive reseating impact that may occur with a single spring, thus improving the product's operational performance and reliability.

[0034] To prevent radial displacement or interference of the springs during operation, ensure that the line of action of the spring force coincides with the axis, and further improve the stability and consistency of the action, in some embodiments, the load-bearing plate 23 has a first protrusion 232 and a second protrusion 233 concentrically arranged along the direction close to the pressure cover 21. The first protrusion 232 is located at the center of the load-bearing plate 23, and the diameter of the first protrusion 232 is smaller than that of the second protrusion 233. The second protrusion 233 is located on the outer periphery of the first protrusion 232. The first spring 221 is located between the first protrusion 232 and the second protrusion 233, and the second spring 222 is located on the outside of the second protrusion 233. Please refer to [link / reference]. Figure 9 This stepped protrusion structure provides precise mounting positioning for two springs of different diameters, effectively preventing the aforementioned situation from occurring.

[0035] To further limit the movement space of the spring, in some embodiments, the pressure cap 21 has a first groove 212 and a second groove 213 that are interconnected along the direction close to the bearing plate 23. The second groove 213 is located on the outer periphery of the first groove 212, the first spring 221 is located in the first groove 212, and the second spring 222 is located in the second groove 213. Please refer to [link / reference]. Figure 8In this embodiment, a first groove 212 and a second groove 213 corresponding to the protrusion on the support plate 23 are provided on the pressure cover 21. The first groove 212 is used to accommodate and position the upper end of the first spring 221, and the second groove 213 is used to accommodate and position the upper end of the second spring 222. The groove on the pressure cover 21 cooperates with the protrusion on the support plate 23 to form a stable spring receiving cavity, ensuring that the first spring 221 and the second spring 222 are always on the same axis during compression and reset, and avoiding spring displacement.

[0036] Please see Figure 1 To facilitate assembly, in some embodiments, the outer casing 1 includes a housing 11 and a top cover 12 and a base 13 respectively screwed to the upper and lower ends of the housing 11. The opening is formed on the base 13, the valve disc 26 abuts against the base 13, and the diaphragm 25 partially protrudes from the base 13 to form a seal at the bottom of the base 13. The top cover 12, the housing 11, and the inner peripheral walls of the base 13 together define the installation space. During factory assembly, the valve assembly 2 is pre-assembled, then inserted from the bottom of the housing 11, and finally the base 13 is tightened to complete the overall assembly. During on-site maintenance, the base 13 can be removed to directly access and remove the valve assembly 2. This split-type housing 1 structure not only reduces the assembly difficulty but also provides more operating space for subsequent maintenance and parts replacement, enhancing the convenience of maintenance.

[0037] To facilitate maintenance personnel in determining whether the valve has been activated without disassembling it, in some embodiments, the pressure relief valve further includes: an indicator rod 5; a third connecting hole 214 is provided at the center of the pressure cap 21; an alarm port 121 is provided at the center of the top cover 12; the indicator rod 5 passes sequentially through the alarm port 121, the third connecting hole 214, and the spring assembly 22 to connect with the load-bearing plate 23; and the indicator rod 5 can slide vertically relative to the pressure cap 21 and the top cover 12. Please refer to [link to relevant documentation]. Figure 2-4 When the valve actuates, the load-bearing plate 23 moves the indicator rod 5 upward, and the top of the indicator rod 5 extends out of the alarm port 121, forming a clear visual indication. Maintenance personnel can intuitively and quickly determine whether the pressure relief valve has been activated simply by observing whether the indicator rod 5 extends out of the alarm port 121, without disassembling the equipment. This provides a visual basis for equipment condition assessment and maintenance decisions, effectively improving the convenience of operation and maintenance.

[0038] The adhesive connection method is simple and reliable, ensuring both synchronous movement of the marker rod 5 and the support plate 23, and facilitating replacement. Therefore, in some embodiments, the marker rod 5 is bonded to the support plate 23 using adhesive.

[0039] In summary, the pressure relief valve provided in this embodiment connects the pressure cap 21, the support plate 23, the support ring 24, the diaphragm 25, and the valve disc 26 into a single module via the connector 3. The pressure cap 21 serves as the top fixing point of the valve assembly 2 and is detachably connected to the outer casing 1. The connector 3 is plugged into and connected to the positioning post 261 on the valve disc 26, enabling quick connection and separation of the valve disc 26 from the upper structure. The spring assembly 22 is pre-installed between the pressure cap 21 and the support plate 23, and its compression is determined by the distance between them. In actual operation, the oil tank is connected to the bottom of the outer casing 1. When the pressure inside the oil tank rises sharply, it impacts the diaphragm 25 at the bottom of the outer casing 1. Under the impact force, the diaphragm 25 drives the support ring 24 and the valve disc 26 to move upward axially. At the same time, under the connection of the connector 3, the bearing plate 23 and the pressure cap 21 move upward synchronously. At this time, a gap appears between the valve disc 26 and the bottom of the outer casing 1, and the oil in the oil tank enters the outer casing 1 through this gap to reduce the pressure inside the oil tank. After the pressure inside the oil tank decreases, the diaphragm 25 drives the entire valve assembly 2 to reset, and a seal is formed again at the bottom of the outer casing 1. When the pressure in the oil tank is too high and the diaphragm 25 is damaged and requires maintenance, simply remove the fixing screw 6 between the pressure cap 21 and the outer casing 1, and the entire valve assembly 2 can be pulled out axially from the installation space of the outer casing 1 in one go. After being pulled out, simply separate the connector 3 from the positioning column 261 to easily replace the diaphragm 25. This structure integrates the core components inside the outer casing 1 into a module, enabling maintenance modes of overall extraction and partial replacement. On-site maintenance time is significantly shortened compared to traditional pressure relief valves, and there is no need to readjust the spring preload, greatly improving maintenance efficiency and ease of operation.

[0040] This specification discloses the present application with reference to the accompanying drawings and also enables those skilled in the art to implement the application, including making and using any device or system, employing suitable materials, and using any combination of methods. The scope of this application is defined by the claimed technical solution and includes other instances that would occur to those skilled in the art. Such other instances shall be considered to fall within the scope of protection defined by the claimed technical solution, provided that they include structural elements that are not different from the literal language of the claimed technical solution, or contain equivalent structural elements that are not substantially different from the literal language of the claimed technical solution.

Claims

1. A pressure relief valve, characterized in that, include: The outer casing (1) has an interior space for installation and an opening at the bottom. The valve assembly (2) is located in the installation space and includes: a connector (3) and a pressure cap (21), a spring assembly (22), a bearing plate (23), a support ring (24), a diaphragm (25) and a valve disc (26) arranged from top to bottom. The pressure cap (21) is screwed to the outer shell (1). The bottom of the connector (3) is provided with a slot (321). The connector (3) passes through the pressure cap (21) and the support plate (23) in sequence and extends downward to the support plate (23). The connector (3) is detachably connected to the support plate (23). The connector (3) can slide relative to the pressure cap (21) in the vertical direction. The spring assembly (22) is located between the pressure cap (21) and the support plate (23). Between them, the valve disc (26) and the support ring (24) are both provided with holes for the diaphragm (25) to pass through. The valve disc (26) is provided with a positioning post (261). The positioning post (261) passes through the diaphragm (25) and the support ring (24) and is inserted into the slot (321). The valve disc (26) abuts against the bottom of the outer shell (1). The diaphragm (25) is recessed downward and partially protrudes from the bottom opening of the outer shell (1) to form a seal at the bottom of the outer shell (1).

2. The pressure relief valve as described in claim 1, characterized in that, The pressure cap (21) has a first connecting hole (211), and the bearing plate (23) has a second connecting hole (231). The connector (3) passes through the first connecting hole (211) and the second connecting hole (231) and is inserted into the positioning post (261). The connector (3) is slidably connected to the first connecting hole (211) and is detachably connected to the bearing plate (23) at the second connecting hole (231). The spring assembly (22) is closer to the center of the bearing plate (23) than the connector (3).

3. The pressure relief valve as described in claim 2, characterized in that, The diameter of the first connecting hole (211) is d1, and the diameter of the connector (3) is d2, wherein 1mm≤d1-d2≤2mm.

4. The pressure relief valve as described in claim 2, characterized in that, The connector (3) includes a guide rod (31) and a transmission rod (32). The upper end of the guide rod (31) passes through the first connecting hole (211) and is slidably connected to the pressure cap (21). The lower end of the guide rod (31) passes through the second connecting hole (231) and is screwed to the transmission rod (32). The bearing plate (23) abuts against the upper end face of the transmission rod (32). The slot (321) is opened at the bottom of the transmission rod (32), and the transmission rod (32) is inserted into the positioning post (261).

5. The pressure relief valve as described in claim 1, characterized in that, Also includes: Fastener (4) passes through the support ring (24) and abuts against the diaphragm (25).

6. The pressure relief valve as described in claim 1, characterized in that, The spring assembly (22) includes a first spring (221) and a second spring (222), wherein the diameter of the second spring (222) is larger than the diameter of the first spring (221), the first spring (221) is located at the center of the bearing plate (23), and the second spring (222) is sleeved on the outer periphery of the first spring (221).

7. The pressure relief valve as described in claim 6, characterized in that, The bearing plate (23) has a first protrusion (232) and a second protrusion (233) arranged concentrically along the direction close to the pressure cover (21). The first protrusion (232) is located at the center of the bearing plate (23), and the diameter of the first protrusion (232) is smaller than that of the second protrusion (233). The second protrusion (233) is located on the outer periphery of the first protrusion (232). The first spring (221) is located between the first protrusion (232) and the second protrusion (233), and the second spring (222) is located on the outer side of the second protrusion (233).

8. The pressure relief valve as described in claim 6, characterized in that, The pressure cap (21) has a first groove (212) and a second groove (213) connected to each other in sequence along the direction close to the bearing plate (23). The second groove (213) is located on the outer periphery of the first groove (212), the first spring (221) is located in the first groove (212), and the second spring (222) is located in the second groove (213).

9. The pressure relief valve as described in claim 1, characterized in that, The outer casing (1) includes: a housing (11) and a top cover (12) and a base (13) respectively screwed to the upper and lower ends of the housing (11). The opening is formed on the base (13). The valve disc (26) abuts against the base (13). The diaphragm (25) protrudes from the base (13) to form a seal at the bottom of the base (13). The inner peripheral walls of the top cover (12), the housing (11) and the base (13) together define the installation space.

10. The pressure relief valve as described in claim 9, characterized in that, Also includes: The signpost (5) has a third connecting hole (214) at the center of the pressure cover (21) and a warning port (121) at the center of the top cover (12). The signpost (5) passes through the warning port (121), the third connecting hole (214), and the spring assembly (22) in sequence and is connected to the bearing plate (23). The signpost (5) can slide relative to the pressure cover (21) and the top cover (12) in the up and down direction.

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