Double-core blow-down valve

Abstract

The utility model provides a double-core blow-down valve, which relates to the technical field of valves and comprises a valve body, the inside of the valve body comprises a first chamber, a second chamber and a third chamber which can be communicated from top to bottom, the first chamber is funnel-shaped, the upper end of the first chamber is provided with a connecting part, and the diameter of the upper end part of the second chamber is larger than that of the lower end part of the first chamber; a rotary cover plate is arranged at the joint of the second chamber and the third chamber, a sewage discharge gate is arranged in the third chamber and located below the rotary cover plate, the sewage discharge gate can be opened and closed by rotating the rotary cover plate, one side of the third chamber is provided with a communicated sewage discharge pipeline, and the side face of the third chamber is further provided with an adjusting hand wheel and a rotary handle; the valve core is approximately gourd-shaped and comprises an upper core body, a pollution discharge adjusting part and a lower core body which are connected with one another; a mounting groove is axially formed in the valve core; the upper end part of the valve rod is mounted in the mounting groove and is in threaded connection with the mounting groove, a limiting piece in axial limiting fit with the valve rod is arranged in the valve body, and the valve core can be driven to move up and down by rotating the valve rod.

Description

TECHNICAL FIELD

[0001] The utility model relates to valve technical field, specifically, it is a sewage valve. BACKGROUND

[0002] For chemical industry, the sewage deposition pool is provided with sewage valve in the daily cleaning process, and the sewage valve is usually used for sewage by ordinary valve, which is not a professional sewage valve designed for sewage demand, because the sewage valve does not have the effect of sewage, so that the dirt deposited at the bottom of the pool cannot be cleaned alone, but the whole pool needs to be cleaned and sewage, which is a serious waste of resources, and the sewage efficiency is low. CONTENT OF THE UTILITY MODEL

[0003] The utility model discloses a double-core sewage valve, which can solve the problems of poor sewage effect and serious waste of resources.

[0004] To solve the above problems, the utility model provides a double-core sewage valve, which comprises: a valve body, the inside of the valve body comprises a first chamber, a second chamber and a third chamber from top to bottom, the first chamber is funnel-shaped, the diameter gradually increases from bottom to top, the upper end of the first chamber is provided with a connecting part, the connecting part is connected with a sewage treatment equipment, the upper end of the second chamber is larger than the lower end of the first chamber, a rotating cover plate is arranged at the connection between the second chamber and the third chamber, a sewage gate is arranged below the rotating cover plate in the third chamber, the sewage gate can be opened and closed by rotating the rotating cover plate, a sewage pipeline is arranged at one side of the third chamber, an adjusting hand wheel and a rotating handle are arranged on the side of the third chamber; a valve core, which is in the shape of a gourd, comprises an upper core body, a sewage adjusting part and a lower core body; the maximum width of the upper core body is larger than that of the lower core body, the upper core body is located in the first chamber and can be axially limited to cooperate with the first chamber; the lower core body is located in the second chamber and can be axially limited to cooperate with the second chamber; the diameter of the sewage adjusting part is smaller than that of the lower core body, and the sewage adjusting part is configured to move up and down in the first chamber and the second chamber; an installation groove is axially arranged in the valve core; a valve rod is arranged at the upper end of the installation groove and is screwed with the valve rod, a limiting part is arranged in the valve body and axially limited to cooperate with the valve rod, and the valve rod can drive the valve core to move up and down by rotating the valve rod; an adjusting hand wheel is provided with a connecting rod arranged in the valve body, the connecting rod is arranged vertically to the valve rod, a bevel gear set is arranged at the inner end of the connecting rod and the lower end of the valve rod, and the valve rod can be rotated in the installation groove by rotating the adjusting hand wheel; a rotating handle is connected with the rotating cover plate, and the rotating handle can drive the rotating cover plate to rotate.

[0005] Further, the upper end portion of the first chamber is provided with a cleaning mechanism, which comprises a high-pressure water interface and a limiting channel communicated with the high-pressure water interface, a check valve core is arranged in the limiting channel, the upper end of the limiting channel is communicated with a water flow channel extending to the axial direction of the first chamber, the inner end of the water flow channel is connected with a rotary water flushing dragon, and a plurality of water injection holes and a hydraulic push rotation nozzle are arranged on the rotary water flushing dragon.

[0006] Further, the lower end of the third chamber is provided with a gear box, the limiting member is located at the top of the gear box, the limiting member is provided with an opening, the rod body portion of the valve rod is arranged to pass through the opening, the lower end of the valve rod is provided with a first tapered portion located in the gear box, the top surface of the first tapered portion abuts against the limiting member, and the first tapered portion is provided with a first gear on the side wall; a side hole is arranged on the side wall of the gear box, the rod body portion of the connecting rod is arranged to pass through the side hole, the inner end portion of the rod body is provided with a matching portion, the diameter of the matching portion is larger than the diameter of the rod body and is limitedly matched with the side wall, the end of the matching portion is provided with a second tapered portion, the second tapered portion is provided with a second gear on the side wall, and the first gear is engaged with the second gear.

[0007] Further, the rotary cover plate is annular, a downward extending lower sleeve is connected to the inner side of the rotary cover plate, the lower sleeve is sleeved on the outer portion of the valve rod, and a limiting convex portion is arranged at the lower end of the lower sleeve; the rotary handle is provided with a handle connecting rod, a handle sliding groove is arranged on the side wall of the third chamber, the handle connecting rod is arranged in the handle sliding groove, and a limiting clamping groove capable of clamping the limiting convex portion is arranged at the inner end of the handle connecting rod.

[0008] Further, the rotary cover plate is annular, a downward extending lower sleeve is connected to the inner side of the rotary cover plate, the lower sleeve is sleeved on the outer portion of the valve rod, and a limiting convex portion is arranged at the lower end of the lower sleeve; the rotary handle is provided with a handle connecting rod, a handle sliding groove is arranged on the side wall of the third chamber, the handle connecting rod is arranged in the handle sliding groove, and a limiting clamping groove capable of clamping the limiting convex portion is arranged at the inner end of the handle connecting rod.

[0009] Further, the inner side of the upper sleeve is provided with a ring groove, the upper end of the valve rod is provided with a limiting ring, the limiting ring is arranged in the ring groove, and the lower end of the limiting ring abuts against the upper end of the ring groove.

[0010] According to the double-core blowdown valve, the internal structure of the blowdown valve is innovated, quantitative blowdown can be realized, cleaning agent is saved, blowdown effect is improved, due to the quantitative and trace blowdown, the blowdown operation of the cleaning sediment pool is simplified, the liquid in the sediment pool can be efficiently utilized, and resource waste is reduced; in addition, the blowdown valve separates the valve core and the valve rod from the outside of the pressure water, greatly reduces the damage of the rotary motion of the valve rod to the sealing member, thereby causing the dripping failure after abrasion, greatly prolongs the service life of the blowdown valve, reduces the daily valve maintenance amount, and reduces the valve scrap rate. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by the provided drawings without creative labor for those skilled in the art.

[0012] Figure 1 A sectional view of a double-core blowdown valve provided by the embodiment of the present application is provided.

[0013] Figure 2 A structural schematic diagram of a double-core blowdown valve provided by the embodiment of the present application is provided.

[0014] Figure 3 An installation schematic diagram of a double-core blowdown valve provided by the embodiment of the present application is provided.

[0015] Figure 4 A sectional view of an open position of a rotating handle of a double-core blowdown valve provided by the embodiment of the present application is provided.

[0016] Figure 5 A detail view of a double-core blowdown valve provided by the embodiment of the present application is provided.

[0017] Figure 6 A structural change diagram of a blowdown method of a double-core blowdown valve provided by the embodiment of the present application is provided.

[0018] Explanation of reference signs:

[0019] 000 - a blowdown device to be installed;

[0020] 100 - a valve body; 110 - a first chamber; 111 - a connecting part; 120 - a second chamber; 130 - a third chamber; 131 - a blowdown pipeline; 132 - a handle sliding groove; 140 - a rotating cover plate; 141 - a lower sleeve; 142 - a limiting convex part; 143 - an upper sleeve; 150 - a blowdown gate; 160 - a gear box; 161 - a limiting part;

[0021] 200 - a valve core; 201 - a mounting groove; 202 - a mounting pipe groove; 210 - an upper core body; 220 - a blowdown adjusting part; 230 - a lower core body;

[0022] 300 - a valve rod; 310 - a first conical part; 320 - a limiting ring;

[0023] 400 - an adjusting hand wheel; 410 - a connecting rod; 411 - a matching part; 412 - a second conical part; 420 - a bevel gear set; 421 - a first gear; 422 - a second gear;

[0024] 500 - Rotary handle; 510 - Handle linkage; 511 - Limiting slot;

[0025] 600-Cleaning mechanism; 610-High-pressure water interface; 620-Limit channel; 621-Check valve core; 630-Water flow channel; 640-Rotating flushing nozzle; 641-Water jet hole; 642-Hydraulic push-rotating nozzle. Detailed Implementation

[0026] To make the above-mentioned objectives, features, and advantages of this utility model more apparent and understandable, specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of this utility model and are not intended to limit it.

[0027] Currently, most commonly used drain valves are essentially ordinary valves. Even new products only aim to make the valve core flapping speed faster. Their internal structure lacks innovation, the draining effect has not been improved, and they are still prone to corrosion and wear. The 300 seal on the valve stem is prone to defects such as running, leaking, dripping, and seepage. There is a lack of special valves specifically designed for draining in this field.

[0028] To address the above problems, this invention innovates the internal structure of the drain valve, providing a dual-core drain valve, such as... Figures 1-5 As shown, the valve body 100 internally includes a first chamber 110, a second chamber 120, and a third chamber 130 that are interconnected from top to bottom. The first chamber 110 is funnel-shaped, and the upper diameter of the second chamber 120 is larger than the lower diameter of the first chamber 110. The shape of the second chamber 120 is as follows: Figure 1 The lantern-shaped structure shown has a diameter that decreases from the middle section to the top and bottom ends. The upper end of the first chamber 110 is provided with a connection part 111 for connecting to the sewage discharge equipment 000, preferably a connecting flange. A sewage discharge pipe 131 communicating with the outside is provided on one side of the third chamber 130.

[0029] The valve body 100 is equipped with a valve core 200, which is nearly gourd-shaped and includes, from top to bottom, an upper core 210, a drain adjustment part 220, and a lower core 230 connected together. The drain adjustment part 220 has the smallest width and is configured to move up and down at the connection between the first chamber 110 and the second chamber 120. The upper core 210 is installed in the first chamber 110 and can be axially limited to cooperate with the first chamber 110. The lower core 230 is installed in the second chamber 120 and can be axially limited to cooperate with the second chamber 120. By adjusting the position and cooperation relationship of the valve core 200, the connectivity between the first chamber 110, the second chamber 120, and the third chamber 130 is adjusted.

[0030] The valve core 200 has an internal mounting groove 201. The upper part of the valve stem 300 is installed in the mounting groove 201 and threaded. In order to achieve relative fixation of the valve stem 300, a limiting member 161 that can cooperate with the valve stem 300 is provided in the third chamber 130. The limiting member 161 has an opening through which the stem of the valve stem 300 passes. A first tapered part 310 is provided at the lower end of the valve stem 300, and its top surface abuts against the lower end surface of the limiting member 161 to achieve axial limiting.

[0031] Specifically, to facilitate the movement of the valve stem 300, a side hole is provided on the side wall of the third chamber 130. The external adjustment handwheel 400 passes through the side hole via a connecting rod 410 and is installed outside the valve body 100. The inner end of the connecting rod 410 is provided with a mating part 411 that engages with the side hole. The diameter of the mating part 411 is larger than the diameter of the side hole, which can prevent the connecting rod 410 from disengaging from the side hole. The inner end of the mating part 411 is provided with a second conical part 412. A second gear 422 is provided on the second conical part 412, and a first gear 421 is provided on the first conical part 310. The first gear 421 and the second gear 422 form a meshing bevel gear set 420. The valve stem 300 is rotated by the external operation of the adjustment handwheel 400. Due to the threaded connection between the valve stem 300 and the valve core 200, the valve core 200 is further driven to move up and down. Among them, the third chamber 130 is located below the limiting member 161 and has a gearbox 160, with a bevel gear set 420 installed inside the gearbox 160.

[0032] A rotating cover plate 140 is provided at the connection between the second chamber 120 and the third chamber 130. A drain gate 150 is located at the lower end of the rotating cover plate 140. The rotating cover plate 140 has several through holes. By rotating its position, the connection between the through holes and the drain gate 150 is adjusted, thereby opening and closing the drain gate 150. Specifically, a downwardly extending lower sleeve 141 is provided on the inner side of the rotating cover plate 140. It is fitted onto the outside of the valve stem 300 and has a limiting protrusion 142 at its lower end. A handle groove 132 for mounting a rotating handle 500 is provided on the side wall of the third chamber 130. The handle connecting rod 510410 can pass through the handle groove 132. Its inner end has a limiting slot 511 that engages with the limiting protrusion. Therefore, by moving the position of the rotating handle 500, the lower sleeve 141 rotates, thereby rotating the rotating cover plate 140. Figure 5 As shown, this is the position of the handle 500 when the sewage gate is opened at 150.

[0033] To improve the stability of the internal structure, an upwardly extending upper sleeve 143 is provided on the rotating cover plate 140. An installation groove 202 is provided inside the lower end of the valve core 200, located outside the installation groove 201. The upper sleeve 143 is installed inside the installation groove 202 and can rotate within it. An annular groove is provided on the lower inner side of the upper sleeve 143. A limiting ring 320 is provided on the valve stem 300, which can be matched with it for limiting, so that the lower end of the limiting ring 320 abuts against the upper end of the annular groove, thereby making the rotating cover plate 140 and the valve stem 300 relatively stable in the axial direction.

[0034] The present invention also includes a cleaning mechanism 600 capable of cleaning the internal chamber, located above the first chamber 110. A high-pressure water interface 610 for connecting to an external high-pressure water jet device is provided on the side wall of the first chamber 110. This interface 610 has an upwardly extending limiting channel 620, inside which is a spherical check valve core 621200. When connected to high-pressure water, the upward force of the water jet can lift the check valve core 621200. Without the force of the high-pressure water jet, it will remain in contact with the high-pressure water interface 610 under the influence of gravity. The 0-point contact closes the valve. The upper end of the limiting channel 620 is connected to an inwardly extending water flow channel 630. When the check valve core 621200 floats up, water flows from the limiting channel 620 into the water flow channel 630. The inner end of the water flow channel 630 is connected to a rotating flushing nozzle 640, which is provided with several water jet holes 641 and a hydraulically driven nozzle 642. The water jet holes 641 can be in multiple directions. Under the action of the hydraulically driven nozzle 642, the rotating flushing nozzle 640 can rotate to achieve thorough cleaning inside.

[0035] The valve body 100 of this invention uses a corrosion-resistant rigid material, and the valve core 200 is made of rigid corrosion-resistant stainless steel. The sealing line of the valve core 200 is ground with a special valve core 200 tool before leaving the factory or during major overhaul to ensure the tightness of the valve core 200 when closed. Through the innovation of the internal structure, it can achieve the purpose of quantitative sewage discharge, timely stop and reduce the discharge of recyclable solvents, thereby reducing the cost of production material consumption.

[0036] In this embodiment, the dual-core drain valve is installed below the equipment to be drained (000) for draining sewage. Figure 3 As shown, when using this dual-core drain valve for draining, as follows: Figure 6 As shown, the specific operating steps include:

[0037] When slag settles, the second chamber 120 of the dual-core drain valve is closed, and the upper core 210 is in a limiting fit with the first chamber 110, which is the normal state of the dual-core drain valve. When the drain equipment 000 is connected to the first chamber 110, its slag sinks into the first chamber 110.

[0038] When the slag is flushed down, the valve stem 300 is driven to rotate around its own axis in the first direction by adjusting the handwheel 400, which drives the valve core 200 to move upward, disengaging the upper core 210 from the first chamber 110, connecting the first chamber 110 to the second chamber 120, and the deposited slag flows down into the second chamber 120.

[0039] Isolate the slag, rotate the adjusting handwheel 400 to drive the valve stem 300 to rotate around its own circumference in the first direction, drive the valve core 200 to move upward, and the lower core 230 and the second chamber 120 are limited to cooperate, closing the second chamber 120;

[0040] Sludge is discharged. Rotating the rotating handle 500 drives the rotating cover 140 to rotate, opening the sewage gate 150. Sludge flows downward into the third chamber 130 and is discharged through the sewage pipe 131.

[0041] After the waste residue is discharged, the turbidity of the discharged water can be observed, or the inner cavity can be cleaned periodically as needed. Rotating the adjusting handwheel 400 drives the valve stem 300 to rotate around its own circumference in the second direction, releasing the lower core 230 from the second chamber 120, and the upper core 210 is not limited to the first chamber 110, so that the first chamber 110, the second chamber 120 and the third chamber 130 are connected, and flushing is carried out by the downward water flow;

[0042] To restore normal operation, the drain valve 150 is closed by rotating the handle 500, and the valve stem 300 is driven to rotate around itself in the second direction in the opposite direction to the first direction by rotating the adjusting handwheel 400. This causes the valve core 200 to move downward, releasing the lower core 230 from the second chamber 120, and limiting the upper core 210 to the first chamber 110, thus restoring the double-core drain valve to normal operation.

[0043] The drain valve provided by this invention has significant advantages over ordinary valves in the prior art. It can quantitatively discharge sewage, specifically targeting small amounts of sludge at the bottom of the sedimentation tank. The discharged sewage and sludge are collected in containers, filtered, and recycled, filling the gap in specialized sewage discharge valves and solving the problems of current technologies. Furthermore, the drain valve of this invention is self-cleaning, capable of high-pressure water jet cleaning inside the valve and at the bottom of the sedimentation tank. The high-pressure water agitates and washes away dirt, solving the problem that ordinary drain valves, once clogged, require disassembly and repair. Problem: Due to the special structure of the valve stem 300, it can be used for a long time without leakage. The valve core 200 bears the water pressure, which can only lead to a tighter closure of the valve core 200, while the valve stem 300 is isolated from the water. Therefore, the pressure-bearing valve core 200 fits tightly and there is no leakage point. When draining, the water pressure entering the drain chamber has been reduced. Even if there is relative movement between the valve stem 300 and the sleeve, the gap area has been coated and filled with anti-corrosion lubricating grease, forming a very thin oil film that plays a sealing role. The pressure of this oil film is much greater than the drain pressure, so there is no way to leak water.

[0044] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

[0045] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0046] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0047] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A dual-core drain valve, characterized in that, include: The valve body (100) comprises, from top to bottom, three interconnected chambers: a first chamber (110), a second chamber (120), and a third chamber (130). The first chamber (110) is funnel-shaped, with its diameter gradually increasing from bottom to top. A connecting part (111) is provided at its upper end, through which it is connected to the sewage discharge equipment (000). The upper end diameter of the second chamber (120) is larger than that of the lower end diameter of the first chamber (110). A rotating cover plate (140) is provided at the connection with the third chamber (130). A drain gate (150) is provided in the third chamber (130) below the rotating cover plate (140). The drain gate (150) can be opened and closed by rotating the rotating cover plate (140). A drain pipe (131) is provided on one side of the third chamber (130). An adjusting handwheel (400) and a rotating handle (500) are also installed on the side of the third chamber (130). The valve core (200) is nearly gourd-shaped and includes an upper core (210), a drain adjustment part (220), and a lower core (230) connected to each other. The maximum width of the upper core (210) is greater than the maximum width of the lower core (230). The upper core (210) is located in the first chamber (110) and can be axially limited therewith. The lower core (230) is located in the second chamber (120) and can be axially limited therewith. The diameter of the drain adjustment part (220) is smaller than that of the lower core (230) and is configured to move up and down inside the first chamber (110) and the second chamber (120). An axial mounting groove (201) is provided inside the valve core (200). The upper part of the valve stem (300) is installed in the mounting groove (201) and threadedly connected thereto. The valve body (100) is provided with a limiting member (161) that is axially limited to the valve stem (300). Rotating the valve stem (300) can drive the valve core (200) to move up and down. The adjusting handwheel (400) is provided with a connecting rod (410) partially installed inside the valve body (100). The connecting rod (410) is arranged perpendicular to the axial direction of the valve stem (300). The inner end of the connecting rod (410) and the lower end of the valve stem (300) are provided with a bevel gear set (420) that meshes with each other. By rotating the adjusting handwheel (400), the valve stem (300) can be driven to rotate in the mounting groove (201). A rotating handle (500) is connected to the rotating cover plate (140). Rotating the rotating handle (500) can drive the rotating cover plate (140) to rotate.

2. The dual-core drain valve according to claim 1, characterized in that, The upper part of the first chamber (110) is provided with a cleaning mechanism (600), including a high-pressure water interface (610) and a limiting channel (620) connected thereto. The limiting channel (620) is equipped with a check valve core (621) (200). The upper end of the limiting channel (620) is connected to a water flow channel (630) extending towards the central axis of the first chamber (110). The inner end of the water flow channel (630) is connected to a rotating flushing nozzle (640). The rotating flushing nozzle (640) is provided with several water jet holes (641) and a hydraulically driven nozzle (642).

3. The dual-core drain valve according to claim 1, characterized in that, The lower end of the third chamber (130) is provided with a gearbox (160), the limiting member (161) is located at the top of the gearbox (160), and the limiting member (161) is provided with an opening. The rod body of the valve stem (300) is configured to pass through the opening, and the lower end of the valve stem (300) is provided with a first conical part (310) located in the gearbox (160). The top surface of the first conical part (310) abuts against the limiting member (161), and a first gear (421) is provided on the side wall of the first conical part (310). The gearbox (160) has a side hole on its side wall. The rod body of the connecting rod (410) is configured to pass through the side hole. The inner end of the rod body has a mating part (411). The diameter of the mating part (411) is larger than the diameter of the rod body and it is matched with the side wall. The end of the mating part (411) has a second tapered part (412). The side wall of the second tapered part (412) has a second gear (422). The first gear (421) meshes with the second gear (422).

4. The dual-core drain valve according to claim 3, characterized in that, The rotating cover plate (140) is annular, and a downwardly extending lower sleeve (141) is connected to its inner side. The lower sleeve (141) is fitted onto the outside of the valve stem (300), and a limiting protrusion (142) is provided at the lower end of the lower sleeve (141). The rotary handle (500) is provided with handle connecting rods (510) and (410). The side wall of the third chamber (130) is provided with handle slide groove (132). The handle connecting rods (510) and (410) are installed in the handle slide groove (132). The inner end of the handle connecting rods (510) and (410) is provided with a limiting slot (511) that can engage with the limiting protrusion (142).

5. The dual-core drain valve according to claim 4, characterized in that, The rotating cover plate (140) is connected to an upwardly extending upper sleeve (143). The lower part of the valve core (200) is provided with an installation tube groove (202) outside the installation groove (201). The upper sleeve (143) is installed in the installation tube groove (202) and can rotate along the central axis of the valve core (200) under the drive of the rotating handle (500).

6. The dual-core drain valve according to claim 5, characterized in that, The inner side of the upper sleeve (143) is provided with an annular groove, and the upper end of the valve stem (300) is provided with a limiting ring (320). The limiting ring (320) is installed in the annular groove, and the lower end of the limiting ring (320) abuts against the upper end of the annular groove.

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