A regulating valve with a flow-limiting buffer structure

Abstract

The application discloses a regulating valve with a flow-limiting buffer structure and relates to the technical field of valves.The scheme comprises a valve body, the top of the valve body is fixedly connected with a top cover and a bottom cover respectively, the top of the top cover is slidably connected with a valve rod penetrating through the top cover, the bottom end of the valve rod is fixedly connected with a conical valve core, the inner wall of the valve body is fixedly connected with a partition plate, and the inside of the partition plate is provided with a conical through hole matched with the conical valve core.The first cleaning mechanism, the second cleaning mechanism and the driving mechanism are arranged, so that impurities adhered to the outer surface of the conical valve core and the inner wall of the conical through hole can be automatically cleaned during the use of the regulating valve, the normal use of the regulating valve is avoided from being affected, the flow-limiting buffer mechanism is arranged, when the pressure of a substance increases, the pressure can be buffered, the flow of the substance can be adjusted and limited, the fine control of the fluid flow is realized, and the impact and vibration caused by the excessively fast flow speed are avoided.

Description

Technical Field

[0001] This invention relates to the field of valve technology, specifically to a regulating valve with a flow-limiting and buffering structure. Background Technology

[0002] In industrial fluid transport systems, regulating valves play a crucial role in adjusting fluid parameters such as flow rate and pressure. However, existing regulating valves are prone to water hammer when faced with sudden flow changes, causing impacts on pipelines and equipment and affecting system stability and service life. Furthermore, traditional regulating valves have limited flow limiting and buffering effects, making it difficult to meet the demands of high-precision and high-stability industrial control. A search revealed Chinese Patent Publication No. CN116006741A, which discloses a pressure-reducing regulating valve with flow limiting and buffering functions, specifically relating to the field of natural gas transport technology. The valve includes a connecting pipe port, a first pressure-reducing spring, and an electromagnetic flowmeter. A flow-limiting mechanism is externally connected to the connecting pipe port, and the first pressure-reducing spring is internally located within the flow-limiting mechanism. An electromagnetic flowmeter is fitted externally to the connecting pipe port.

[0003] The above-mentioned technical solution, through the setting of the limiting collar, buffer valve core, worm gear tooth plate and the first worm gear, can maximize the dispersion and guidance of the gas pressure inside the first counterflow channel, so that the pressure reducing valve can adjust the pressure according to the gas pressure and achieve pressure control when the instantaneous flow is too large. However, during use, some substances may contain impurities, which will adhere to the outer surface of the valve core and the inner wall of the valve hole. The above-mentioned technical solution cannot clean the corresponding positions, which will affect normal use. In addition, the valve body structure is fixed, and all the components are installed inside the valve body, which is inconvenient for later disassembly and maintenance. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a regulating valve with a flow-limiting buffer structure, which solves the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a regulating valve with a flow-limiting buffer structure, comprising a valve body, a top cover and a bottom cover fixedly connected to the top of the valve body, a valve stem slidably connected through the top of the top cover, a conical valve core fixedly connected to the bottom end of the valve stem, a partition plate fixedly connected to the inner wall of the valve body, a conical through hole cooperating with the conical valve core being opened inside the partition plate, a first cleaning mechanism cooperating with the conical valve core being installed on the upper surface of the partition plate, a second cleaning mechanism cooperating with the conical through hole being installed inside the conical through hole, a driving mechanism cooperating with the first and second cleaning mechanisms being installed on the top of the bottom cover, an input pipe and an output end fixedly connected to both sides of the outer surface of the valve body, a flow-limiting buffer mechanism being installed inside the input pipe, and a reset mechanism cooperating with the valve stem being installed on the top of the top cover;

[0006] The first cleaning mechanism includes an annular frame rotatably connected to the upper surface of the partition. Two first spring telescopic rods are symmetrically fixedly connected to the top of the annular frame. A first connecting block is fixedly connected to the top of the first spring telescopic rod. A crossbar is slidably connected through the outer surface of the first connecting block. A first scraper that mates with the outer surface of the conical valve core is fixedly connected to one end of the crossbar.

[0007] Through the above technical solution, when the annular frame rotates, it will drive the first scraper to rotate, which can scrape the outer surface of the conical valve core to prevent impurities from adhering to the surface of the conical valve core, thereby affecting the normal use of the regulating valve. The first spring telescopic rod can make the first scraper always keep in contact with the surface of the conical valve core when the conical valve core rises and falls, and push the first scraper to retract when the conical valve core closes.

[0008] Preferably, a baffle is fixedly connected to one end of the crossbar, and a first return spring is fixedly connected between the baffle and the first connecting block.

[0009] Through the above technical solution, the first reset spring can automatically drive the first scraper to reset when the conical valve core rises to a certain height, so that the first scraper can fit against the surface of the conical valve.

[0010] Preferably, the second cleaning mechanism includes a second spring telescopic rod disposed inside the conical through hole, a second connecting block fixedly connected to the top end of the second spring telescopic rod, a second scraper rotatably connected to both sides of the second connecting block and cooperating with the inner wall of the conical through hole, a torsion spring fixedly connected between the outer surface of the second scraper and the second connecting block, and a pressure rod cooperating with the bottom of the conical valve core fixedly connected to the top of the second connecting block.

[0011] Through the above technical solution, the rotation of the second spring telescopic rod can drive the second scraper to rotate, which can scrape off the impurities adhering to the inner wall of the conical through hole, so as to avoid affecting the sealing effect. When the conical valve core descends, the second connecting block is squeezed by the pressure rod, and the second scraper will retract. When the conical valve core rises, the second scraper can contact the inner wall of the conical through hole under the action of the second spring telescopic rod and the torsion spring.

[0012] Preferably, the drive mechanism includes a bracket fixedly connected to the top of the bottom cover, a first rotating shaft rotatably connected transversely through the inside of the bracket, a turbine fixedly connected to one end of the first rotating shaft, the bottom end of the second spring telescopic rod passing through the top of the bracket and rotatably connected to the bracket, a second rotating shaft rotatably connected through the upper surface of the partition, a first bevel gear fixedly connected to the bottom ends of both the second rotating shaft and the second spring telescopic rod, and two second bevel gears meshing with the first bevel gear fixedly connected to the outer surface of the first rotating shaft.

[0013] With the above technical solution, when the material passes through the regulating valve, it will drive the worm gear to rotate, and under the action of the second bevel gear and the first bevel gear, it can drive the second spring telescopic rod and the second rotating shaft to rotate respectively.

[0014] Preferably, a spur gear is fixedly connected to the top end of the second rotating shaft, and an external gear ring that meshes with the spur gear is fixedly connected to the outer surface of the annular frame.

[0015] Through the above technical solution, the rotation of the second rotating shaft can drive the ring frame to rotate via the spur gear and the external gear ring.

[0016] Preferably, the flow limiting buffer mechanism includes a support ring threaded inside the input pipe, a central pipe fixedly connected to one side of the support ring, a plurality of flow limiting holes opened on the outer surface of the central pipe, an adjusting cover slidably fitted on the outer surface of the central pipe, a connecting plate fixedly connected to one end of the adjusting cover, and a second return spring fixedly connected between the connecting plate and the support ring.

[0017] With the above technical solution, when the pressure of the material entering is too high, the regulating cover will be squeezed and buffered by the action of the second reset spring. The squeezing cover will then block the flow-limiting orifice, reducing the area through which the material flows. This achieves precise control of the fluid flow rate, effectively reducing the fluid velocity and avoiding impacts and vibrations caused by excessive flow velocity.

[0018] Preferably, a rotating block is fixedly connected to one side of the central tube.

[0019] Through the above technical solution, the rotating block facilitates the rotation of the central tube, thereby enabling the installation and disassembly of the flow-limiting buffer mechanism.

[0020] Preferably, the reset mechanism includes a support rod fixedly connected to the top of the top cover, a lower shell fixedly connected to the top end of the support rod, a valve stem slidably connected to the bottom of the lower shell, a top plate fixedly connected to the top end of the valve stem, an upper shell fixedly connected to the top of the lower shell, and a third reset spring provided between the upper shell and the top plate.

[0021] Through the above technical solution, the third reset spring will automatically drive the valve stem and conical valve core to reset according to the pressure of the substance, thereby achieving the adjustment effect.

[0022] This invention provides a regulating valve with a flow-limiting buffer structure. It has the following beneficial effects:

[0023] 1. This regulating valve with a flow-limiting buffer structure can automatically clean impurities adhering to the outer surface of the conical valve core and the inner wall of the conical through hole during the use of the regulating valve through a first cleaning mechanism, a second cleaning mechanism and a driving mechanism, so as to avoid affecting the normal use of the regulating valve and thus solve the problem that the existing regulating valve cannot perform internal self-cleaning, which affects its normal use.

[0024] 2. This regulating valve with a flow-limiting and buffering structure can not only buffer the pressure when the material pressure increases, but also regulate and limit the flow of the material, thereby achieving precise control of the fluid flow rate. It can effectively reduce the fluid velocity and avoid the impact and vibration caused by excessive flow velocity.

[0025] 3. This regulating valve with a flow-limiting and buffering structure allows the first cleaning mechanism, the second cleaning mechanism, the drive mechanism, and the flow-limiting and buffering mechanism to be disassembled for maintenance and replacement through the top cover, bottom cover, and rotating block. This not only facilitates maintenance but also reduces maintenance costs. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0027] Figure 2 This is a schematic diagram of the internal structure of the valve body of the present invention;

[0028] Figure 3 This is a partial structural schematic diagram of the present invention;

[0029] Figure 4 This is a schematic diagram of the structure of the first cleaning mechanism, the second cleaning mechanism, and the driving mechanism of the present invention;

[0030] Figure 5 This is a schematic diagram of the current limiting buffer mechanism of the present invention;

[0031] Figure 6This is a schematic diagram of the internal structure of the current limiting buffer mechanism of the present invention;

[0032] Figure 7 This is a schematic diagram of the internal structure of the reset mechanism of the present invention.

[0033] In the diagram, 1. Valve body; 2. Top cover; 3. Bottom cover; 4. Valve stem; 5. Conical valve core; 6. Partition plate; 7. Conical through hole; 8. First cleaning mechanism; 81. Annular frame; 82. First spring telescopic rod; 83. First connecting block; 84. Crossbar; 85. First scraper; 86. Baffle; 87. First return spring; 9. Second cleaning mechanism; 91. Second spring telescopic rod; 92. Second connecting block; 93. Second scraper; 94. Pressure rod; 10. Drive mechanism; 101. Bracket; 102. First rotating shaft; 103. Turbine; 104, Second shaft; 105, First bevel gear; 106, Second bevel gear; 107, Spur gear; 108, External gear ring; 11, Input pipe; 12, Output end; 13, Flow limiting buffer mechanism; 131, Support ring; 132, Central pipe; 133, Flow limiting hole; 134, Adjustment cover; 135, Connecting plate; 136, Second return spring; 137, Rotating block; 14, Reset mechanism; 141, Support rod; 142, Lower shell; 143, Top plate; 144, Upper shell; 145, Third return spring. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1: As Figures 1 to 4As shown, a regulating valve with a flow-limiting buffer structure includes a valve body 1. A top cover 2 and a bottom cover 3 are fixedly connected to the top of the valve body 1. A valve stem 4 is slidably connected through the top of the top cover 2. A conical valve core 5 is fixedly connected to the bottom end of the valve stem 4. A partition 6 is fixedly connected to the inner wall of the valve body 1. A conical through hole 7 that cooperates with the conical valve core 5 is opened inside the partition 6. A first cleaning mechanism 8 that cooperates with the conical valve core 5 is installed on the upper surface of the partition 6. The first cleaning mechanism 8 includes an annular frame 81 rotatably connected to the upper surface of the partition 6. Two first spring telescopic rods 82 are symmetrically fixedly connected to the top of the annular frame 81. A first connecting block 83 is fixedly connected to the top end of the first spring telescopic rod 82. A crossbar 84 is slidably connected through the outer surface of the first connecting block 83. A first scraper 85 that cooperates with the outer surface of the conical valve core 5 is fixedly connected to one end of the crossbar 84. A baffle 86 is fixedly connected to one end of the crossbar 84, and a first return spring 87 is fixedly connected between the baffle 86 and the first connecting block 83.

[0036] When the annular frame 81 rotates, it drives the first scraper 85 to rotate, which can scrape the outer surface of the conical valve core 5 to prevent impurities from adhering to the surface of the conical valve core 5 and thus affecting the normal use of the regulating valve. The first spring telescopic rod 82 can make the first scraper 85 always keep in contact with the surface of the conical valve core 5 when the conical valve core 5 rises and falls, and push the first scraper 85 to retract when the conical valve core 5 closes. The first return spring 87 can automatically drive the first scraper 85 to return to its original position when the conical valve core 5 rises to a certain height, so that the first scraper 85 can keep in contact with the surface of the conical valve.

[0037] A second cleaning mechanism 9 that mates with the tapered through hole 7 is installed inside the tapered through hole 7. The second cleaning mechanism 9 includes a second spring telescopic rod 91 disposed inside the tapered through hole 7. A second connecting block 92 is fixedly connected to the top of the second spring telescopic rod 91. A second scraper 93 that mates with the inner wall of the tapered through hole 7 is rotatably connected to both sides of the second connecting block 92. A torsion spring is fixedly connected between the outer surface of the second scraper 93 and the second connecting block 92. A pressure rod 94 that mates with the bottom of the tapered valve core 5 is fixedly connected to the top of the second connecting block 92.

[0038] The rotation of the second spring telescopic rod 91 causes the second scraper 93 to rotate, which can scrape off impurities adhering to the inner wall of the conical through hole 7, thus avoiding affecting the sealing effect. When the conical valve core 5 descends, the pressure rod 94 squeezes the second connecting block 92, and the second scraper 93 will retract. When the conical valve core 5 rises, the second scraper 93 can contact the inner wall of the conical through hole 7 under the action of the second spring telescopic rod 91 and the torsion spring.

[0039] A drive mechanism 10, which cooperates with the first cleaning mechanism 8 and the second cleaning mechanism 9, is installed on the top of the bottom cover 3. The drive mechanism 10 includes a bracket 101 fixedly connected to the top of the bottom cover 3. A first rotating shaft 102 is rotatably connected through the interior of the bracket 101. A turbine 103 is fixedly connected to one end of the first rotating shaft 102. The bottom end of the second spring telescopic rod 91 passes through the top of the bracket 101 and is rotatably connected to the bracket 101. A second rotating shaft 104 is rotatably connected through the upper surface of the partition 6. A first bevel gear 105 is fixedly connected to the bottom ends of both the second rotating shaft 104 and the second spring telescopic rod 91. Two second bevel gears 106, which mesh with the first bevel gear 105, are fixedly connected to the outer surface of the first rotating shaft 102. A spur gear 107 is fixedly connected to the top of the second rotating shaft 104. An external gear ring 108, which meshes with the spur gear 107, is fixedly connected to the outer surface of the annular frame 81.

[0040] When the material passes through the regulating valve, it will drive the worm gear to rotate. Under the action of the second bevel gear 106 and the first bevel gear 105, the second spring telescopic rod 91 and the second rotating shaft 104 can be rotated respectively. The rotation of the second rotating shaft 104 can drive the annular frame 81 to rotate through the spur gear 107 and the external gear ring 108.

[0041] Example 2: Figure 1 , Figure 5 and Figure 6 As shown, an input pipe 11 and an output end 12 are fixedly connected to both sides of the outer surface of the valve body 1, respectively. A flow-limiting buffer mechanism 13 is installed inside the input pipe 11. The flow-limiting buffer mechanism 13 includes a support ring 131 threadedly connected inside the input pipe 11. A central pipe 132 is fixedly connected to one side of the support ring 131. Multiple flow-limiting holes 133 are opened on the outer surface of the central pipe 132. An adjusting cover 134 is slidably sleeved on the outer surface of the central pipe 132. A connecting plate 135 is fixedly connected to one end of the adjusting cover 134. A second return spring 136 is fixedly connected between the connecting plate 135 and the support ring 131. A rotating block 137 is fixedly connected to one side of the central pipe 132.

[0042] When the pressure of the material entering is too high, it will squeeze the regulating cover 134 and buffer it under the action of the second return spring 136. The squeeze cover will then block the flow limiting hole 133, reducing the area through which the material flows, thereby achieving precise control of the fluid flow rate. This can effectively reduce the fluid velocity and avoid the impact and vibration caused by excessive flow velocity. The rotating block 137 facilitates the rotation of the central tube 132, thereby enabling the installation and disassembly of the flow limiting buffer mechanism 13.

[0043] Example 3: As Figure 1 and Figure 7As shown, a reset mechanism 14 that cooperates with the valve stem 4 is installed on the top of the top cover 2. The reset mechanism 14 includes a support rod 141 fixedly connected to the top of the top cover 2. The top end of the support rod 141 is fixedly connected to the lower shell 142. The valve stem 4 is slidably connected to the bottom of the lower shell 142. The top end of the valve stem 4 is fixedly connected to the top plate 143. The top of the lower shell 142 is fixedly connected to the upper shell 144. A third reset spring 145 is provided between the upper shell 144 and the top plate 143.

[0044] The third return spring 145 will automatically drive the valve stem 4 and the conical valve core 5 to return to their original positions according to the pressure of the substance, thereby achieving the adjustment effect.

[0045] Working principle: The third return spring 145 will automatically drive the valve stem 4 and the conical valve core 5 to return to their original positions according to the pressure of the substance, thereby achieving the adjustment effect.

[0046] When the material passes through the regulating valve, it will drive the worm gear to rotate. Under the action of the second bevel gear 106 and the first bevel gear 105, the second spring telescopic rod 91 and the second rotating shaft 104 can be rotated respectively. The rotation of the second rotating shaft 104 can drive the annular frame 81 to rotate through the spur gear 107 and the external gear ring 108.

[0047] When the annular frame 81 rotates, it drives the first scraper 85 to rotate, which can scrape the outer surface of the conical valve core 5 to prevent impurities from adhering to the surface of the conical valve core 5 and thus affecting the normal use of the regulating valve. The first spring telescopic rod 82 can make the first scraper 85 always keep in contact with the surface of the conical valve core 5 when the conical valve core 5 rises and falls, and push the first scraper 85 to retract when the conical valve core 5 closes. The first return spring 87 can automatically drive the first scraper 85 to return to its original position when the conical valve core 5 rises to a certain height, so that the first scraper 85 can keep in contact with the surface of the conical valve.

[0048] The rotation of the second spring telescopic rod 91 causes the second scraper 93 to rotate, which can scrape off impurities adhering to the inner wall of the conical through hole 7, thus avoiding affecting the sealing effect. When the conical valve core 5 descends, the pressure rod 94 squeezes the second connecting block 92, and the second scraper 93 will retract. When the conical valve core 5 rises, the second scraper 93 can contact the inner wall of the conical through hole 7 under the action of the second spring telescopic rod 91 and the torsion spring.

[0049] When the pressure of the material entering is too high, it will squeeze the regulating cover 134 and buffer it under the action of the second return spring 136. The squeeze cover will then block the flow limiting hole 133, reducing the area through which the material flows, thereby achieving precise control of the fluid flow rate. This can effectively reduce the fluid velocity and avoid the impact and vibration caused by excessive flow velocity. The rotating block 137 facilitates the rotation of the central tube 132, thereby enabling the installation and disassembly of the flow limiting buffer mechanism 13.

[0050] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0051] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A regulating valve with a flow throttling buffer structure, comprising a valve body (1), characterized in that: The top and top of the valve body (1) are fixedly connected with top cover (2) and bottom cover (3), the top of the top cover (2) is slidably connected with valve stem (4), the bottom end of the valve stem (4) is fixedly connected with conical valve core (5), the inner wall of the valve body (1) is fixedly connected with partition (6), the inside of the partition (6) is provided with conical hole (7) matched with conical valve core (5), the upper surface of the partition (6) is provided with first cleaning mechanism (8) matched with conical valve core (5), the inside of the conical hole (7) is provided with second cleaning mechanism (9) matched with conical hole (7), the top of the bottom cover (3) is provided with driving mechanism (10) matched with first cleaning mechanism (8) and second cleaning mechanism (9), the outer surface of the valve body (1) is fixedly connected with input pipe (11) and output end (12) respectively, the inside of the input pipe (11) is provided with flow limiting buffer mechanism (13), the top of the top cover (2) is provided with reset mechanism (14) matched with valve stem (4); The first cleaning mechanism (8) comprises an annular frame (81) rotatably connected to the upper surface of the partition (6), two first spring telescopic rods (82) are fixedly connected to the top of the annular frame (81) in a symmetrical manner, a first connecting block (83) is fixedly connected to the top end of the first spring telescopic rod (82), a cross rod (84) is slidably connected through the outer surface of the first connecting block (83), and a first scraper (85) matched with the outer surface of the conical valve core (5) is fixedly connected to one end of the cross rod (84); One end of the cross rod (84) is fixedly connected with a baffle (86), and a first reset spring (87) is fixedly connected between the baffle (86) and the first connecting block (83); The second cleaning mechanism (9) comprises a second spring telescopic rod (91) arranged in the conical hole (7), a second connecting block (92) is fixedly connected to the top end of the second spring telescopic rod (91), second scrapers (93) matched with the inner wall of the conical hole (7) are rotatably connected to the two sides of the second connecting block (92), torsional springs are fixedly connected between the outer surfaces of the second scrapers (93) and the second connecting block (92), and a pressure rod (94) matched with the bottom of the conical valve core (5) is fixedly connected to the top of the second connecting block (92).

2. The control valve with a flow throttling buffer structure according to claim 1, characterized in that: The driving mechanism (10) includes a support (101) fixedly connected to the top of the bottom cover (3), a first rotating shaft (102) rotatably connected through the inside of the support (101), one end of the first rotating shaft (102) fixedly connected with a turbine (103), the bottom end of the second spring telescopic rod (91) penetrating through the top of the support (101) and rotatably connected with the support (101), the upper surface of the partition (6) rotatably connected with a second rotating shaft (104), the second rotating shaft (104) and the bottom end of the second spring telescopic rod (91) both fixedly connected with a first bevel gear (105), the outer surface of the first rotating shaft (102) fixedly connected with two second bevel gears (106) engaged with the first bevel gear (105).

3. The control valve with a flow-restricting buffer structure according to claim 2, characterized in that: The top end of the second rotating shaft (104) is fixedly connected with a straight gear (107), and the outer surface of the annular frame (81) is fixedly connected with an outer gear ring (108) engaged with the straight gear (107).

4. The control valve with a flow throttling buffer structure according to claim 1, characterized in that: The flow limiting buffer mechanism (13) includes a support ring (131) threadedly connected in the input pipe (11), a center pipe (132) fixedly connected to one side of the support ring (131), a plurality of flow limiting holes (133) formed in the outer surface of the center pipe (132), a adjusting cover (134) slidably sleeved on the outer surface of the center pipe (132), a connecting plate (135) fixedly connected to one end of the adjusting cover (134), and a second reset spring (136) fixedly connected between the connecting plate (135) and the support ring (131).

5. The control valve with a flow throttling buffer structure according to claim 4, characterized in that: One side of the center pipe (132) is fixedly connected with a rotating block (137).

6. The control valve with a flow throttling buffer structure according to claim 1, characterized in that: The reset mechanism (14) includes a support rod (141) fixedly connected to the top of the top cover (2), a lower shell (142) fixedly connected to the top end of the support rod (141), the valve rod (4) penetratingly and slidably connected to the bottom of the lower shell (142), a top plate (143) fixedly connected to the top end of the valve rod (4), an upper shell (144) fixedly connected to the top of the lower shell (142), and a third reset spring (145) arranged between the upper shell (144) and the top plate (143).

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