Frictionless spring safety valve

Abstract

A frictionless spring-loaded safety valve, belonging to the field of pressure vessel protection, addresses the problem of high friction on large-diameter valve stems in steam turbine extraction pipelines. It includes an upper guide assembly and a lower guide assembly. The upper guide assembly includes a second permanent magnet ring, and the lower guide assembly includes a first permanent magnet ring. An upper magnetic ring is fitted onto the upper part of the valve stem assembly, and a lower magnetic ring is fitted onto the lower part. All three permanent magnet rings—the first, second, lower, and upper—are axially magnetized. The upper and lower magnetic rings are arranged with the same pole facing each other, and the polarity directions of the upper and second permanent magnet rings are the same, forming a magnetic gap between them. Similarly, the lower magnetic ring and the first permanent magnet ring have the same polarity direction, also forming a magnetic gap. The radial magnetic force of the second permanent magnet ring on the upper magnetic ring points towards the axis of the upper guide assembly, and the radial magnetic force of the first permanent magnet ring on the lower magnetic ring points towards the axis of the lower guide assembly. The valve stem assembly has zero friction.

Description

Technical Field

[0001] This invention belongs to the field of pressure vessel protection, and particularly relates to a frictionless spring-loaded safety valve. Background Technology

[0002] Spring-loaded safety valves are installed on the turbine extraction line of the unit. They automatically release a certain amount of steam when the steam pressure exceeds the design value, preventing overpressure in the extraction line and protecting the normal operation of the turbine. A qualified spring-loaded safety valve can quickly rise to its full stroke under the set pressure; when the pressure drops to the specified range, the safety valve quickly returns to its seat and seals.

[0003] During normal operation, the spring-loaded safety valve used in traditional steam turbine extraction pipelines maintains a seal by balancing the force of the medium, the sealing force, and the frictional force between the valve stem and guide components (spring preload F1 ≥ set pressure P). set ×Valve disc action area A + Frictional force F f +Sealing force F m ).

[0004] When the turbine extraction pipeline experiences overpressure to a certain level, the steam force overcomes the combined force of the spring's full opening force, the sealing force, and the valve stem friction, causing the valve to open. The system overpressure standard is no more than 1.03 times the set pressure, i.e., the spring's full opening force F1 ≤ 1.03 times the set pressure P. set ×Valve disc action area A - Friction force F f -Sealing force F m .

[0005] When the pressure in the protected container is released and the system pressure drops sufficiently, the spring force can overcome the combined force of the medium force and the valve stem friction, maintaining a certain sealing force on the sealing surface to ensure a seal after the valve reseating. The standard is that this preload should be no less than 90% of the set pressure, i.e., the spring preload F1 ≥ 0.9 times the set pressure P. set ×Valve disc action area A - Friction force F f -Sealing force F m .

[0006] With the continuous development of generating units, the diameter of safety valves in turbine extraction pipelines is becoming increasingly larger. Due to the larger spring size and the increasing difficulty in machining the guide components, the friction between the valve stem and the guide components is increasing, resulting in excessively large opening and closing pressure differentials and overpressure coefficients that fail to meet standards. Furthermore, the larger the spring size, the greater the spring eccentricity, and the greater the friction.

[0007] Therefore, the safety valves in the turbine extraction pipelines of current generating units need to overcome the friction of the valve stem during both opening and reseating. The lower the valve stem friction, the smaller the valve opening and closing pressure difference and overpressure coefficient. However, due to the eccentricity of the spring and the continuously increasing size of the valve opening, the friction between the valve stem and the guide sleeve in existing spring-type safety valves is too large, resulting in a large valve opening and closing pressure difference and an excessively large overpressure coefficient, leading to serious steam waste. Summary of the Invention

[0008] The purpose of this invention is to provide a frictionless spring-loaded safety valve to solve the problem of increasing friction between the valve stem and guide components as the diameter of safety valves in turbine extraction pipelines becomes larger. The technical solution adopted by this invention is as follows:

[0009] A frictionless spring-loaded safety valve includes a stationary component and a movable component. The stationary component includes a spring cover, a cooler, and a valve body connected sequentially from top to bottom. The valve body is a three-way component, with a lower opening for the medium inlet and a right opening for the medium outlet. A valve seat is provided on the lower opening of the valve body, and a lower guide component is provided in the upper opening of the valve body. The lower guide component includes a support plate, and a first magnetic isolation ring, a first permanent magnet ring, and a guide sleeve are provided in the inner hole of the support plate. The first permanent magnet ring and the first magnetic isolation ring are inner and outer sleeved together in the upper part of the inner hole of the support plate. The top of the first magnetic isolation ring has a retaining structure extending in the axial direction, which abuts against and blocks the upper end face of the first permanent magnet ring. The guide sleeve is located in the lower part of the inner hole of the support plate, and the first permanent magnet ring and the guide sleeve are coaxially abutted together. The spring cover is a hollow component with a lower opening. An upper guide assembly is provided on the top wall. The upper guide assembly includes an adjusting screw. The inner hole of the adjusting screw contains a second permanent magnet ring and a second magnetic isolation ring that are coaxially opposed. The movable assembly includes a valve stem assembly. An upper magnetic ring is sleeved on the upper part of the valve stem assembly. A lower magnetic ring and a third magnetic isolation ring that are opposed are sleeved on the lower part of the valve stem assembly. The valve stem assembly passes through the inner holes of the lower guide assembly and the upper guide assembly. The lower end of the valve stem assembly is connected to the valve disc. The first permanent magnet ring, the second permanent magnet ring, the lower magnetic ring, and the upper magnetic ring are all axially magnetized magnetic rings. The upper magnetic ring and the lower magnetic ring are arranged with the same pole facing each other. The polarity directions of the upper magnetic ring and the second permanent magnet ring are the same. A magnetic force gap is formed between the outer circumference of the upper magnetic ring and the inner circumference of the second permanent magnet ring. The polarity directions of the lower magnetic ring and the first permanent magnet ring are the same. A magnetic force gap is formed between the outer circumference of the lower magnetic ring and the inner circumference of the first permanent magnet ring.

[0010] Furthermore, a backflush disc is fitted around the outer periphery of the valve disc, the outer periphery of the valve disc is provided with a flange, the inner periphery of the backflush disc is provided with a recessed stop, and the pressure ring is connected to the backflush disc by a first screw, the pressure ring pressing the flange into the recessed stop.

[0011] Furthermore, the upper end of the valve disc is provided with a stroke adjustment sleeve, the lower end of the valve stem assembly is inserted into the stroke adjustment sleeve, and the valve stem assembly and the stroke adjustment sleeve are connected by a cylindrical pin.

[0012] Furthermore, a semi-circular groove is provided on the lower end face of the valve stem assembly, a valve disc pad is provided at the bottom of the stroke adjustment sleeve, a semi-circular groove is provided on the upper end face of the valve disc pad, the upper part of the steel ball mates with the semi-circular groove of the lower valve stem, and the lower part of the steel ball mates with the semi-circular groove of the valve disc pad.

[0013] Furthermore, the valve stem assembly includes an upper valve stem, a middle valve stem, and a lower valve stem connected sequentially from top to bottom. An upper magnetic ring is sleeved on the bottom of the upper valve stem, and a lower magnetic ring and a third magnetic isolation ring are sleeved on the bottom of the middle valve stem.

[0014] Furthermore, the spring cover is provided with an upper spring seat, a return spring and a lower spring seat that abut against each other in sequence, and the return spring is sleeved on the valve stem assembly;

[0015] A first recessed groove is provided on the lower end face of the lower spring seat. A universal pad is provided in the first recessed groove. A conical groove is provided on the lower end face of the universal pad. A retaining ring is sleeved on the valve stem assembly. The upper end face of the retaining ring is a convex spherical surface. The conical surface of the conical groove is tangentially engaged with the convex spherical ring.

[0016] A second recess is provided on the upper end face of the upper spring, and the thrust bearing is set in the second recess. The adjusting screw and the thrust bearing are abutted against each other through the bearing pad.

[0017] Furthermore, the adjusting screw is threadedly connected to the top wall of the spring cover, and a thin nut is threadedly connected to the adjusting screw, which abuts against and locks the top wall of the spring cover.

[0018] Furthermore, the spring cover is equipped with several lifting rings.

[0019] Furthermore, the cooler is a cylindrical component with an opening at the bottom, and several balance holes are provided on the side wall of the cooler and several balance holes are provided on the support plate.

[0020] Furthermore, a small cover is provided at the upper end of the spring cover, and a valve stem nut is provided inside the small cover. The upper end of the valve stem assembly passes through the upper guide assembly and is connected to the valve stem nut. One end of the handle is hinged to the left outer wall of the small cover by a pin, and the other end of the handle is bent downward. The right end of the shift fork is hinged to the right outer wall of the small cover. The shift fork passes through the small cover from below the valve stem nut, and the left end of the shift fork abuts against the upper side of the handle.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] When the valve stem assembly is coaxial with the lower and upper guide assemblies, the resultant radial magnetic force of the second permanent magnet ring on the upper magnetic ring is zero, and the resultant radial magnetic force of the first permanent magnet ring on the lower magnetic ring is zero. The valve stem assembly is suspended, and there is no friction between it and the lower and upper guide assemblies. When the valve stem assembly deviates from the axis of the lower and upper guide assemblies, the resultant radial magnetic force of the second permanent magnet ring on the upper magnetic ring points towards the axis of the upper guide assembly, and the resultant radial magnetic force of the first permanent magnet ring on the lower magnetic ring points towards the axis of the lower guide assembly, causing the valve stem assembly to return to its equilibrium position and re-suspend, eliminating friction. Compared with traditional spring-loaded safety valves, when the turbine extraction pipeline is overpressurized to a certain pressure, the steam force only needs to overcome the full opening force and sealing force of the spring before the valve stem assembly slides upward within the upper and lower guide assemblies, causing the valve to open. This eliminates the friction of the valve stem assembly and results in a smaller overpressure coefficient. When the pressure in the protected container is released and the system pressure drops sufficiently, the spring force only needs to overcome the force of the medium. The valve stem assembly slides downward within the upper and lower guide assemblies, and the valve returns to its seat. Compared with traditional spring-loaded safety valves, the opening and closing pressure difference is smaller. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the present invention;

[0024] Figure 2 This is a structural schematic diagram of the valve stem assembly;

[0025] Figure 3 This is a structural schematic diagram of the upper guide component;

[0026] Figure 4 This is a schematic diagram of the structure of the lower guide component.

[0027] In the diagram: 1-Valve body, 2-Recoil plate, 3-Screw, 4-Pressure ring, 5-Valve disc, 6-Cylindrical pin, 7-Stroke adjustment sleeve, 8-Lower guide assembly, 81-Support plate, 82-Second screw, 83-Guide sleeve, 84-Third screw, 85-First magnetic isolation ring, 86-First permanent magnet ring, 9-Cooler, 10-Double-ended screw, 11-Fasting nut, 12-Spring cover, 13-Handle, 14-Thrust bearing, 15-Bearing pad, 16-Lifting eye, 17-Thin nut, 18-Small cover, 19- 20-Pin, 21-Fork, 22-Valve stem nut, 22-Upper guide assembly, 221-Second magnetic isolation ring, 222-Second permanent magnet ring, 223-Adjusting screw, 23-Upper spring seat, 24-Return spring, 25-Valve stem assembly, 251-Lower valve stem, 252-Third magnetic isolation ring, 253-Lower magnetic ring, 254-Middle valve stem, 255-Upper magnetic ring, 256-Upper valve stem, 26-Lower spring seat, 27-Universal pad, 28-Retaining ring, 29-Steel ball, 30-Valve disc pad, 31-Valve seat. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0029] The connections mentioned in this invention are divided into fixed connections and detachable connections. Fixed connections, also known as non-detachable connections, include but are not limited to conventional fixed connection methods such as folded connections, riveted connections, adhesive connections, and welded connections. Detachable connections include but are not limited to conventional disassembly methods such as bolted connections, snap-fit ​​connections, pin connections, and hinged connections. When a specific connection method is not explicitly defined, it is assumed that at least one existing connection method can be found to achieve this function, and those skilled in the art can choose according to their needs. For example, a welded connection can be chosen for fixed connections, and a bolted connection can be chosen for detachable connections.

[0030] The present invention will be further described in detail below with reference to the accompanying drawings. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0031] Example: Figures 1-4As shown, a frictionless spring-type safety valve includes a stationary component and a movable component. The stationary component includes a spring cover 12, a cooler 9, and a valve body 1 connected sequentially from top to bottom. The valve body 1 is a three-way component, with the lower opening of the valve body 1 serving as the medium inlet and the right opening of the valve body 1 serving as the medium outlet. A valve seat 31 is provided on the lower opening of the valve body 1, and a lower guide component 8 is provided in the upper opening of the valve body 1. The lower guide component 8 includes a support plate 81, and a first magnetic isolation ring 85, a first permanent magnet ring 86, and a guide sleeve 83 are provided in the inner hole of the support plate 81. The guide sleeve 83 is slidably engaged with the valve stem assembly 25. The permanent magnet ring 86 and the first magnetic isolation ring 85 are fitted together in the upper part of the inner hole of the support plate 81. The top of the first magnetic isolation ring 85 is provided with a retaining structure extending in the axial direction. The retaining structure abuts against and covers the upper end face of the first permanent magnet ring 86. The guide sleeve 83 is provided in the lower part of the inner hole of the support plate 81. The first permanent magnet ring 86 and the guide sleeve 83 are coaxially abutted together. A number of first threaded holes are drilled and tapped between the first magnetic isolation ring 85 and the support plate 81. A number of third screws 84 are connected to the number of first threaded holes one by one. A number of second threaded holes are drilled and tapped between the guide sleeve 83 and the support plate 81. A plurality of second screws 82 are connected one-to-one with a plurality of second threaded holes. The spring cover 12 is a hollow component with a lower opening. An upper guide assembly 22 is provided on the top wall of the spring cover 12. The upper guide assembly 22 includes an adjusting screw 223. A second permanent magnet ring 222 and a second magnetic isolation ring 221 are provided in the inner hole of the adjusting screw 223. The movable component includes a valve stem assembly 25. An upper magnetic ring 255 is sleeved on the upper part of the valve stem assembly 25. A lower magnetic ring 253 and a third magnetic isolation ring 252 are sleeved on the lower part of the valve stem assembly 25. The valve stem assembly 25 passes through the inner hole of the lower guide assembly 8. The inner hole of the upper guide assembly 22 and the lower end of the valve stem assembly 25 are connected to the valve disc 5. The first permanent magnet ring 86, the second permanent magnet ring 222, the lower magnetic ring 253 and the upper magnetic ring 255 are all axially magnetized magnetic rings. The upper magnetic ring 255 and the lower magnetic ring 253 are arranged opposite each other with the same pole. The polarity directions of the upper magnetic ring 255 and the second permanent magnet ring 222 are the same. A magnetic force gap is formed between the outer periphery of the upper magnetic ring 255 and the inner periphery of the second permanent magnet ring 222. The polarity directions of the lower magnetic ring 253 and the first permanent magnet ring 86 are the same. A magnetic force gap is formed between the outer periphery of the lower magnetic ring 253 and the inner periphery of the first permanent magnet ring 86.

[0032] The lower ends of several double-ended screws 10 are connected to the valve body 1, and the upper ends of several double-ended screws 10 pass through the flange holes of the spring cover 12 and are connected to the fastening nut 11. The cooler 9 is sandwiched between the spring cover 12 and the valve body 1.

[0033] When the valve stem assembly 25 is coaxial with the lower guide assembly 8 and the upper guide assembly 22, the radial magnetic force of the second permanent magnet ring 222 on the upper magnetic ring 255 is zero, and the radial magnetic force of the first permanent magnet ring 86 on the lower magnetic ring 253 is zero. The valve stem assembly 25 is suspended and there is no friction between it and the lower guide assembly 8 and the upper guide assembly 22. When the valve stem assembly 25 deviates from the axis of the lower guide assembly 8 and the upper guide assembly 22, the radial magnetic force of the second permanent magnet ring 222 on the upper magnetic ring 255 points towards the axis of the upper guide assembly 22, and the radial magnetic force of the first permanent magnet ring 86 on the lower magnetic ring 253 points towards the axis of the lower guide assembly 8, so that the valve stem assembly 25 returns to the equilibrium position and the valve stem assembly 25 is resuspended to eliminate friction.

[0034] Compared to traditional spring-loaded safety valves, when the turbine extraction pipeline is overpressurized to a certain level, the steam force only needs to overcome the full opening force and sealing force of the spring. The valve stem assembly 25 then slides upward within the upper guide assembly 22 and lower guide assembly 8, causing the valve to open. This eliminates the frictional force of the valve stem assembly 25, resulting in a smaller overpressure coefficient. When the pressure in the protected vessel is released and the system pressure drops sufficiently, the spring force only needs to overcome the medium force. The valve stem assembly 25 then slides downward within the upper guide assembly 22 and lower guide assembly 8, causing the valve to reseat. This results in a smaller opening and closing pressure differential compared to traditional spring-loaded safety valves.

[0035] A backflush disc 2 is sleeved on the outer periphery of the valve disc 5. The outer periphery of the valve disc 5 is provided with a flange, and the inner periphery of the backflush disc 2 is provided with a recessed stop. The pressure ring 4 is connected to the backflush disc 2 by the first screw 3, and the pressure ring 4 presses the flange into the recessed stop.

[0036] The upper end of the valve disc 5 is provided with a stroke adjustment sleeve 7, and the lower end of the valve stem assembly 25 passes through the stroke adjustment sleeve 7. The valve stem assembly 25 and the stroke adjustment sleeve 7 are connected by a cylindrical pin 6. If there is a machining error, the actual stroke of the safety valve is ensured to match the design stroke by adjusting the actual relative assembly position of the stroke adjustment sleeve 7 and the valve stem assembly 25.

[0037] A semi-circular groove is formed on the lower end face of the valve stem assembly 25. A valve disc pad 30 is provided at the bottom of the stroke adjustment sleeve 7. A semi-circular groove is formed on the upper end face of the valve disc pad 30. The upper part of the steel ball 29 mates with the semi-circular groove of the lower valve stem 251, and the lower part of the steel ball 29 mates with the semi-circular groove of the valve disc pad 30. The valve stem assembly 25 and the valve disc 5 can be automatically aligned through the engagement of the steel ball 29, ensuring the perpendicularity between the axis of the valve stem assembly 25 and the sealing surface of the valve disc 5.

[0038] The valve stem assembly 25 includes an upper valve stem 256, a middle valve stem 254 and a lower valve stem 251 connected sequentially from top to bottom. An upper magnetic ring 255 is sleeved on the bottom of the upper valve stem 256, and a lower magnetic ring 253 and a third magnetic isolation ring 252 are sleeved on the bottom of the middle valve stem 254.

[0039] The spring cover 12 is provided with an upper spring seat 23, a return spring 24 and a lower spring seat 26 that abut against each other in sequence, and the return spring 24 is sleeved on the valve stem assembly 25;

[0040] A first recessed groove is provided on the lower end face of the lower spring seat 26. A universal pad 27 is provided in the first recessed groove. A conical groove is provided on the lower end face of the universal pad 27. A retaining ring 28 is sleeved on the valve stem assembly 25. The upper end face of the retaining ring 28 is a convex spherical surface. The conical surface of the conical groove is tangentially engaged with the convex spherical ring line.

[0041] A second recess is provided on the upper end surface of the upper spring, and the thrust bearing 14 is set in the second recess. The adjusting screw 223 and the thrust bearing 14 abut against each other through the bearing pad 15.

[0042] The adjusting screw 223 is threadedly connected to the top wall of the spring cover 12. A thin nut 17 is threadedly connected to the adjusting screw 223, and the thin nut 17 is locked against the top wall of the spring cover 12.

[0043] The spring cover 12 is provided with several hanging rings 16.

[0044] The cooler 9 is a cylindrical component with an opening at the bottom. Several balance holes are provided on the side wall of the cooler 9 and several balance holes are provided on the support plate 81. Through the several balance holes on the cooler 9 and several balance holes on the support plate 81, the pressure in the valve chamber before the valve is opened can be kept consistent with the atmospheric pressure, thus avoiding the problem that the back pressure at the rear end of the valve disc 5 is too low and the valve is not easy to reseat when fully opened.

[0045] The upper end of the spring cover 12 is provided with a small cover 18, and the valve stem nut 21 is provided inside the small cover 18. The upper end of the valve stem assembly 25 passes through the upper guide assembly 22 and is connected to the valve stem nut 21. One end of the handle 13 is hinged to the left outer wall of the small cover 18 through the pin 19, and the other end of the handle 13 is bent downward. The right end of the shift fork 20 is hinged to the right outer wall of the small cover 18. The shift fork 20 passes through the small cover 18 from below the valve stem nut 21, and the left end of the shift fork 20 abuts against the upper side of the handle 13. When the system needs to be purged, the handle 13 is pulled upward, and the handle 13 pushes the left end of the shift fork 20 upward, which in turn pushes the valve stem nut 21 upward through the shift fork 20, so that the valve stem assembly 25 can drive the valve disc 5 to slide open the valve, thereby realizing the purging and cleaning inside the valve body 1.

[0046] The above embodiments are merely illustrative examples of the present invention and do not limit its scope of protection. Those skilled in the art can make partial changes to them, as long as they do not exceed the spirit and essence of the present invention, they are all within the scope of protection of the present invention.

Claims

1. A frictionless spring-loaded safety valve, characterized in that: It includes a stationary component and a movable component; the stationary component includes a spring cover (12), a cooler (9) and a valve body (1) connected sequentially from top to bottom. The valve body (1) is a three-way component. The lower opening of the valve body (1) is the medium inlet, and the right opening of the valve body (1) is the medium outlet. A valve seat (31) is provided on the lower opening of the valve body (1). A lower guide component (8) is provided in the upper opening of the valve body (1). The lower guide component (8) includes a support plate (81). The inner hole of the support plate (81) is provided with a first magnetic isolation ring (85), a first permanent magnet ring (86) and a guide sleeve (83). The first permanent magnet ring (86) and the first magnetic isolation ring (85) are fitted together in the upper part of the inner hole of the support plate (81). The top of the first magnetic isolation ring (85) is provided with a baffle structure extending in the axial direction. The baffle structure abuts against and blocks the upper end face of the first permanent magnet ring (86). The guide sleeve (83) is provided in the lower part of the inner hole of the support plate (81). The first permanent magnet ring (86) and the guide sleeve (83) are coaxially abutted. The spring cover (12) is a hollow component with a bottom opening. The top wall of the spring cover (12) is provided with an upper guide assembly (22). The upper guide assembly (22) includes an adjustment mechanism. The adjusting screw (223) has a second permanent magnet ring (222) and a second magnetic isolation ring (221) that are coaxially opposed in the inner hole. The movable component includes a valve stem assembly (25). An upper magnetic ring (255) is sleeved on the upper part of the valve stem assembly (25), and a lower magnetic ring (253) and a third magnetic isolation ring (252) that are coaxially opposed in the lower part of the valve stem assembly (25) are sleeved on the lower part of the valve stem assembly (25). The valve stem assembly (25) passes through the inner hole of the lower guide assembly (8) and the inner hole of the upper guide assembly (22). The lower end of the valve stem assembly (25) is connected to the valve disc (5). The first permanent magnet... Ring (86), second permanent magnet ring (222), lower magnetic ring (253) and upper magnetic ring (255) are all axially magnetized magnetic rings. The upper magnetic ring (255) and lower magnetic ring (253) are arranged with the same pole facing each other. The polarity direction of the upper magnetic ring (255) and the second permanent magnet ring (222) is the same. A magnetic force gap is formed between the outer periphery of the upper magnetic ring (255) and the inner periphery of the second permanent magnet ring (222). The polarity direction of the lower magnetic ring (253) and the first permanent magnet ring (86) is the same. A magnetic force gap is formed between the outer periphery of the lower magnetic ring (253) and the inner periphery of the first permanent magnet ring (86). A semi-circular groove is provided on the lower end face of the valve stem assembly (25), and a valve disc pad (30) is provided at the bottom of the stroke adjustment sleeve (7). A semi-circular groove is provided on the upper end face of the valve disc pad (30). The upper part of the steel ball (29) is engaged with the semi-circular groove of the lower valve stem (251), and the lower part of the steel ball (29) is engaged with the semi-circular groove of the valve disc pad (30).

2. The frictionless spring-loaded safety valve according to claim 1, characterized in that: A backflush disc (2) is sleeved on the outer periphery of the valve disc (5). The outer periphery of the valve disc (5) is provided with a flange, and the inner periphery of the backflush disc (2) is provided with a recessed stop. The pressure ring (4) is connected to the backflush disc (2) by a first screw (3). The pressure ring (4) presses the flange into the recessed stop.

3. The frictionless spring-loaded safety valve according to claim 1, characterized in that: The upper end of the valve disc (5) is provided with a stroke adjustment sleeve (7), and the lower end of the valve stem assembly (25) is inserted into the stroke adjustment sleeve (7). The valve stem assembly (25) and the stroke adjustment sleeve (7) are connected by a cylindrical pin (6).

4. A frictionless spring-loaded safety valve according to claim 1, characterized in that: The valve stem assembly (25) includes an upper valve stem (256), a middle valve stem (254) and a lower valve stem (251) connected from top to bottom. An upper magnetic ring (255) is sleeved on the bottom of the upper valve stem (256), and a lower magnetic ring (253) and a third magnetic isolation ring (252) are sleeved on the bottom of the middle valve stem (254).

5. A frictionless spring-loaded safety valve according to claim 1, characterized in that: The spring cover (12) is provided with an upper spring seat (23), a return spring (24) and a lower spring seat (26) that abut against each other in sequence. The return spring (24) is sleeved on the valve stem assembly (25). A first recessed groove is provided on the lower end face of the lower spring seat (26), and a universal pad (27) is provided in the first recessed groove. A conical groove is provided on the lower end face of the universal pad (27). A retaining ring (28) is sleeved on the valve stem assembly (25). The upper end face of the retaining ring (28) is a convex spherical surface. The conical surface of the conical groove is tangentially fitted to the convex spherical ring line. A second recess is provided on the upper end face of the upper spring, and the thrust bearing (14) is set in the second recess. The adjusting screw (223) and the thrust bearing (14) abut against each other through the bearing pad (15).

6. A frictionless spring-loaded safety valve according to claim 1, characterized in that: The adjusting screw (223) is threaded to the top wall of the spring cover (12), and a thin nut (17) is threaded on the adjusting screw (223). The thin nut (17) is locked against the top wall of the spring cover (12).

7. A frictionless spring-loaded safety valve according to claim 1, characterized in that: The spring cover (12) is provided with several hanging rings (16).

8. A frictionless spring-loaded safety valve according to claim 1, characterized in that: The cooler (9) is a cylindrical component with an opening at the bottom. Several balance holes are provided on the side wall of the cooler (9), and several balance holes are provided on the support plate (81).

9. A frictionless spring-loaded safety valve according to any one of claims 1-8, characterized in that: The upper end of the spring cover (12) is provided with a small cover (18), and the small cover (18) is provided with a valve stem nut (21). The upper end of the valve stem assembly (25) passes through the upper guide assembly (22) and is connected to the valve stem nut (21). One end of the handle (13) is hinged to the left outer wall of the small cover (18) through a pin (19). The other end of the handle (13) is bent downward. The right end of the shift fork (20) is hinged to the right outer wall of the small cover (18). The shift fork (20) passes through the small cover (18) from below the valve stem nut (21). The left end of the shift fork (20) abuts against the upper side of the handle (13).

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