Natural gas emergency shut-off valve

Abstract

The application relates to the technical field of natural gas pipeline valves, in particular to a natural gas emergency cut-off valve which comprises a valve body, a fastening cover detachably mounted at the upper end of the valve body, a reset cylinder penetrating the inner end of the fastening cover, a valve pipe fixedly installed at the inner end of the valve body, the reset cylinder being located above the valve pipe, a supporting rod fixedly connected to the inner side left end of the valve pipe, a sealing plug penetrating the outer surface of the supporting rod, a cut-off device arranged in the reset cylinder, and a communication pipe fixedly connected to the outer surface of the valve pipe, wherein the input end of the communication pipe penetrates the inside of the reset cylinder. The natural gas flow state dynamic response control is realized through the multistage linkage structure of the pressure plug, the locking ring, the limiting rod and the like arranged in the valve body. When the natural gas flows in the normal pressure range, the mechanical balance is formed between the pressure plug and the sealing sleeve, and the locking ring only has a slight displacement, so that the cut-off mechanism is not triggered by mistake due to the slight fluctuation of the natural gas pressure, and the stability and the anti-interference ability of the system operation are improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of natural gas pipeline valves, in particular to a natural gas emergency cut-off valve. BACKGROUND

[0002] With the continuous popularization and development of city gas systems, natural gas, as an efficient and clean energy, has been widely used in many fields such as industry, commerce and residential life. However, natural gas is a flammable and explosive gas. Once leakage occurs during transportation and use, it is easy to cause fire, explosion and other safety accidents, resulting in personnel casualties and property losses. In order to improve the safety of the gas system, an emergency cut-off valve is usually arranged in the gas pipeline system to quickly cut off the gas source when an abnormal situation occurs, so as to prevent the accident from further expanding.

[0003] After searching, it is found that the prior art with the publication number CN217762130U discloses an improved natural gas emergency cut-off valve. The valve body is fixedly embedded with a shell, the inner wall of the shell is fixedly embedded with a valve core sealing pad, the valve core sealing pad is slidably sleeved with a valve core, the inner wall of the valve body is fixedly embedded with a valve core seat, the valve core is inserted into the valve core seat, the valve core is fixedly provided with a valve rod, the shell is fixedly embedded with a rod sleeve, the valve rod is slidably sleeved with the rod sleeve, the inner wall of the shell is fixedly embedded with a sealing ring, the valve rod is slidably attached to the sealing ring, the outer wall of the shell is fixedly provided with a gas cylinder, the valve rod is fixedly provided with a connecting plate, and the piston rod of the gas cylinder is fixedly connected with the connecting plate. The scheme can detect the air tightness of the joint through the gas sensor, can cooperate with the gas cylinder to open and close the valve core in the case of gas leakage, and the sealing cover adopts a bayonet structure, so that installation and disassembly are facilitated, and the accuracy of the gas detector can be regularly maintained and inspected.

[0004] Therefore, based on the above search and in combination with the existing technology, the emergency cut-off valve can effectively identify and tolerate the slight pressure fluctuation generated during normal natural gas transportation. However, it is easy to misjudge the non-abnormal state as an abnormal state, thereby triggering the cut-off mechanism, causing accidental interruption of natural gas, affecting normal use, and at the same time, many cut-off valves are respectively provided with different reset structures or operation modes when dealing with overpressure and underpressure. The user needs to select the corresponding reset steps according to the trigger reason, the reset logic is complex, and misresetting or device damage may be caused due to judgment errors or improper operation, which has certain use safety hazards. Therefore, the application provides a natural gas emergency cut-off valve. SUMMARY

[0005] The application aims to provide a natural gas emergency cut-off valve to solve the problems in the background art.

[0006] In order to achieve the above object, the present application provides the following technical scheme: a natural gas emergency cut-off valve, comprising a valve body, a fastening cover is detachably installed at the upper end of the valve body, a reset cylinder is arranged at the inner end of the fastening cover, a valve pipe is fixedly installed at the inner end of the valve body, the reset cylinder is located above the valve pipe, a support rod is fixedly connected to the inner side left end of the valve pipe, a sealing plug is arranged at the outer surface of the support rod, a cut-off device is arranged in the reset cylinder, which is used for detecting abnormal gas flow, a gas column is arranged at the inner end of the reset cylinder, when the cut-off device is triggered, the gas column moves upward, a communication pipe is fixedly connected to the outer surface of the valve pipe, and the input end of the communication pipe is arranged in the reset cylinder.

[0007] As a further scheme of the present application, the cut-off device comprises a support frame, which is fixedly installed at the inner end of the reset cylinder, the inner end of the communication pipe is arranged with a center cylinder, and the support frame is fixedly connected with the center cylinder, by arranging the support frame in the reset cylinder and fixing the center cylinder in the communication pipe to the support frame, the stable installation of the internal components of the cut-off device is realized, the action deviation caused by loose structure during gas flow or device triggering is avoided, and the structural strength and working reliability of the device as a whole are improved.

[0008] As a further scheme of the present application, the end of the gas column close to the communication pipe is fixedly installed with a passive plug, the passive plug is arranged in the inner end of the reset cylinder, a plurality of lifting rods are rotatably installed at the outer surface of the center cylinder, the plurality of lifting rods are arranged in a ring shape, and the free ends of the lifting rods all point to the bottom end of the passive plug, by arranging the passive plug at the end of the gas column close to the communication pipe and making it arranged in the inner end of the reset cylinder, and by arranging the plurality of lifting rods in a ring shape at the outer surface of the center cylinder and making the free ends of the lifting rods all point to the bottom end of the passive plug, the precise driving of the passive plug in the triggered state of the device is effectively realized, and the cut-off action is ensured to be fast and stable.

[0009] As a further scheme of the present application, the side of the passive plug close to the lifting rods is provided with a guide rail, the end of the lifting rods close to the passive plug is rotatably installed with a sliding block, and the sliding block is slidably connected with the guide rail, when the lifting rods rotate, the end portions thereof gather towards each other, and the guide rail moves upward under the action, by arranging the guide rail at the side of the passive plug close to the lifting rods and rotatably installing the sliding block at the end portion of the lifting rods, making the sliding block slidably connected with the guide rail, when the lifting rods rotate, the sliding block can gather along the direction of the guide rail and drive the guide rail to move upward, and the stable linkage control of the passive plug is realized.

[0010] As a further scheme of the present application, the reset cylinder is internally provided with a pushing ring, the pushing ring is sleeved on the outside of the plurality of lifting rods, the pushing ring and the reset cylinder are connected through a trigger spring, under the elastic force of the trigger spring, the pushing ring is always subjected to upward force, the pushing ring and the reset cylinder are connected through the trigger spring, the pushing ring always maintains upward pre-tightening force under the spring elastic force, it is ensured that the lifting rod can stably bear force and accurately respond during the triggering process, and the action sensitivity and reliability of the cutting device are improved.

[0011] As a further scheme of the present application, the inner end of the air column is provided with a sealing sleeve, the inner end of the air column is fixedly installed with a through pipe, the through pipe is arranged in the inside of the sealing sleeve, one end of the through pipe away from the air column is fixedly connected with a support plate, and the support plate is fixedly connected with the center cylinder.

[0012] As a further scheme of the present application, the outer surface of the sealing sleeve is fixedly sleeved with a locking ring, the outer surface of the center cylinder is fixedly sleeved with a guide frame, the guide frame and the locking ring are parallel to each other, and a guide groove is formed in the outer periphery of the guide frame, so that the stable cooperation and guidance of the locking ring and the guide frame are realized, the locking ring is guided to move along a predetermined track, deviation and jamming of the locking ring are prevented, the operation stability and sealing performance of the internal mechanism of the valve are improved, and the accurate and reliable emergency cutting action is ensured.

[0013] As a further scheme of the present application, the inner end of the guide frame is provided with a plurality of limiting rods, the limiting rods correspond to the lifting rods, one end of the limiting rods away from the guide frame is fixedly connected with a pressure receiving block, the pressure receiving block is in contact with the outer surface of the locking ring, so that the locking ring can accurately respond to pressure changes during the operation of the device, the pressure is effectively transmitted to the limiting rods and the lifting rods through the pressure receiving block, accurate action control is realized, and the response sensitivity and reliability of the emergency cutting valve are improved.

[0014] As a further scheme of the present application, the inner end of the guide frame is slidably installed with a limiting sliding block, the outer surface of the limiting sliding block is in contact with the outer surface of the lifting rod, the limiting rods are fixedly connected with the limiting sliding block, the inner end of the communication pipe is sleeved with a pressure plug, the outer surface of the pressure plug is provided with a locking rod, and the upper end of the locking rod is fixedly installed with an isolation frame.

[0015] As a further scheme of the present application, the inner end of the valve pipe is fixedly installed with a center rod, the center rod corresponds to the support rod, the outer surface of the center rod is fixedly installed with a center ring, the inner end of the center ring is rotatably installed with a driving cylinder, one end of the center ring away from the center rod is fixedly installed with a support disc, the outer surface of the support disc is slidably installed with a plurality of locking blocks, the locking blocks are arranged in a ring shape and are in contact with the outer surface of the sealing plug.

[0016] Compared with the prior art, the present application has the following advantages:

[0017] 1. The application realizes dynamic response control of natural gas flow state by setting pressure plug, locking ring, limiting rod and other multi-stage linkage structures in the valve body. When natural gas flows in the normal pressure range, mechanical balance is formed between the pressure plug and the sealing sleeve, and the locking ring only has a slight displacement, thereby avoiding false triggering of the cut-off mechanism due to slight fluctuations in natural gas pressure, and improving the stability and anti-interference ability of the system operation.

[0018] 2. In the case of triggering cut-off under natural gas underpressure or overpressure, the application completes resetting through unified resetting structure and operation steps, avoids the hidden danger of inconsistent resetting paths in traditional devices due to different triggering reasons, and effectively reduces system abnormalities or safety risks caused by judgment errors or improper operation in the use process. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of a natural gas emergency cut-off valve;

[0020] Figure 2 It is a structural schematic diagram of the valve body;

[0021] Figure 3 It is a structural schematic diagram of the inside of the resetting cylinder;

[0022] Figure 4 It is a structural schematic diagram of the lifting rod;

[0023] Figure 5 It is a structural schematic diagram of the inside of the center cylinder;

[0024] Figure 6 It is Figure 5 It is a structural schematic diagram of the center cylinder and the communication pipe;

[0025] Figure 7 It is a disassembly diagram of the inside structure of the center cylinder and the communication pipe;

[0026] Figure 8 It is a structural schematic diagram of the inside of the valve pipe;

[0027] Figure 9 It is a structural schematic diagram of the sealing plug and the center ring;

[0028] Figure 10 It is a disassembly diagram of the structure between the locking block and the center ring.

[0029] In the figure: 1, valve body; 2, fastening cover;

[0030] 101, resetting cylinder; 102, gas column; 103, support frame; 104, passive plug; 105, through pipe; 106, sealing sleeve; 107, locking ring; 108, support plate;

[0031] 201. Valve pipe; 202. Center rod; 203. Passive rod; 204. Support rod; 205. Sealing plug; 206. Locking block; 207. Center ring; 208. Support plate; 209. Drive cylinder; 210. Pull rod;

[0032] 301. Connecting pipe; 302. Locking rod; 303. Stabilizing spring; 304. Pressure plug; 305. Isolation frame;

[0033] 401. Center cylinder; 402. Trigger spring; 403. Lifting rod; 404. Push ring; 405. Sliding block; 406. Guide rail; 407. Auxiliary push block; 408. Mating ring; 409. Guide frame; 410. Pressure block; 411. Limiting rod; 412. Limiting slider; 413. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1: Please refer to Figures 1-3 , Figure 7 A natural gas emergency shut-off valve includes a valve body 1, a fastening cover 2 detachably installed on the upper end of the valve body 1, a reset cylinder 101 passing through the inner end of the fastening cover 2, a valve pipe 201 fixedly installed on the inner end of the valve body 1, the reset cylinder 101 being located above the valve pipe 201, a support rod 204 being fixedly connected to the inner left end of the valve pipe 201 by bolts, and a sealing plug 205 passing through the outer surface of the support rod 204. The valve pipe 201 is funnel-shaped, so when the sealing plug 205 moves toward the center of the valve pipe 201, its outer surface will contact the inner wall of the valve pipe 201, thereby achieving the effect of blocking the gas flow.

[0036] The reset cylinder 101 is equipped with a cut-off device to detect abnormal gas flow. An air column 102 passes through the inner end of the reset cylinder 101. When the cut-off device is triggered, the air column 102 moves upward. A connecting pipe 301 is fixedly connected to the outer surface of the valve pipe 201, and the input end of the connecting pipe 301 passes through the inside of the reset cylinder 101.

[0037] like Figures 2-4As shown, the cutting device includes a support frame 103 fixedly installed at the inner end of the reset cylinder 101, the inner end of the communication pipe 301 is provided with a center cylinder 401, and the support frame 103 is fixedly connected with the center cylinder 401. Specifically, the outer surface of the center cylinder 401 is provided with a sealing rubber ring in contact with the inner wall of the center cylinder 401 for increasing air tightness. The air column 102 is fixedly welded with a passive plug 104 at one end close to the communication pipe 301, the passive plug 104 is provided at the inner end of the reset cylinder 101, the outer surface of the center cylinder 401 is rotatably installed with a plurality of lifting rods 403 through a rotating shaft, the plurality of lifting rods 403 are arranged in a ring shape, and the free ends of the lifting rods 403 all point to the bottom end of the passive plug 104;

[0038] The side of the passive plug 104 close to the lifting rods 403 is provided with a guide rail 406, the one end of the lifting rods 403 close to the passive plug 104 is rotatably installed with a sliding block 405, and the sliding block 405 is slidably connected with the guide rail 406. When the lifting rods 403 rotate, the end portions thereof gather towards the one end close to each other, the guide rail 406 moves upward under the action and pushes the passive plug 104 to move. Specifically, the guide rail 406 is provided with a cooperating ring 408 between the guide rail 406 and the passive plug 104, the bottom end of the cooperating ring 408 is fixedly welded with a plurality of auxiliary push blocks 407 arranged in a ring shape, and the auxiliary push blocks 407 correspond to the sliding blocks 405. The auxiliary push blocks 407 are triangular, and when the sliding block 405 moves towards the auxiliary push block 407, the outer surface thereof is in contact with the inclined surface of the auxiliary push block 407 (the sliding block 405 first contacts the auxiliary push block 407, and drives the auxiliary push block 407 to move upward during the continuous movement without moving beyond the auxiliary push block 407). The lifting rods 403 are arranged in an inclined state, and the rotational movement thereof is always limited within a non-perpendicular angle range, so as to ensure that the passive plug 104 has a reliable downward movement space.

[0039] The reset cylinder 101 is provided with a pushing ring 404 inside, the pushing ring 404 is sleeved outside the plurality of lifting rods 403, and the pushing ring 404 is connected with the reset cylinder 101 through the trigger spring 402. Under the elastic force of the trigger spring 402, the pushing ring 404 is always subjected to an upward force.

[0040] Example 2: Please refer to Figures 4-6The natural gas emergency cut-off valve is based on the basis of embodiment 1, the inner end of the air column 102 is provided with a sealing sleeve 106, the outer surface of the sealing sleeve 106 is provided with a sealing rubber ring, and is attached to the inner wall of the air column 102 to increase the air tightness, a closed air pressure space is formed between the sealing sleeve 106 and the air column 102, the gas pressure in the space continuously exerts a downward force on the sealing sleeve 106, the inner end of the air column 102 is fixedly installed with a guide pipe 105, the guide pipe 105 penetrates the inside of the sealing sleeve 106, the end of the guide pipe 105 away from the air column 102 is fixedly connected with a support plate 108, and the support plate 108 is fixedly connected with the center cylinder 401;

[0041] The outer surface of the sealing sleeve 106 is fixedly provided with a locking ring 107, the outer surface of the center cylinder 401 is fixedly provided with a guide frame 409, and the guide frame 409 is parallel to the locking ring 107, a guide groove is formed in the outer periphery of the guide frame 409, and the corresponding part of the lifting rod 403 is arranged in the guide groove, the rotation range of the lifting rod 403 is limited through the groove rail cooperation structure, and the movement of the lifting rod 403 along the set track is ensured, a plurality of limiting rods 411 penetrate the inner end of the guide frame 409, the limiting rods 411 correspond to the lifting rod 403, the limiting rods 411 and the guide frame 409 are connected through a return spring 413, and the end of the limiting rod 411 away from the guide frame 409 is fixedly welded with a pressure receiving block 410, and the pressure receiving block 410 is in contact with the outer surface of the locking ring 107;

[0042] Specifically, the locking ring 107 is spindle-shaped (i.e., thick in the middle and thin at both ends), the pressure receiving block 410 is located at the center of the locking ring 107 in the initial state, so that the return spring 413 is in a compressed state at this time, the inner end of the guide frame 409 is slidingly installed with a limiting slider 412, the outer surface of the limiting slider 412 is in contact with the outer surface of the lifting rod 403, the limiting rod 411 is fixedly connected with the limiting slider 412, when the sealing sleeve 106 moves upward or downward, the pressure receiving block 410 slides towards the upper end or the lower end of the locking ring 107 at this time, and the limiting rod 411 moves away from the guide frame 409 under the elastic force of the return spring 413, in this state, the lifting rod 403 is released from the constraint of the limiting rod 411, and the rotating movement is realized.

[0043] As shown in Figure 3 , Figures 7-8 , the inner end of the communication pipe 301 is provided with a pressure plug 304, the pressure plug 304 is positioned by the symmetrically arranged upper and lower stabilizing springs 303, and under the balance of spring elasticity, the pressure plug 304 is stably kept at the center position of the communication pipe 301, wherein in the process that the natural gas flows through the valve pipe 201, the fluid pressure drives the pressure plug 304 to have an upward trend, at the same time, the closed air pressure space formed between the sealing sleeve 106 and the air column 102 generates a reverse force, and the two form a mechanical balance state;

[0044] The outer surface of the pressure plug 304 is provided with the locking rod 302, and the upper end of the locking rod 302 is fixedly welded with the isolation frame 305, the isolation frame 305 is in a hollow state, and is fixedly connected with the bottom end of the supporting plate 108, so that the movement force of the supporting plate 108 can be better transmitted to the locking rod 302.

[0045] As shown in Figures 8-10 The inner end of the valve pipe 201 is fixedly installed with the center rod 202 through bolts, the center rod 202 corresponds to the supporting rod 204, the outer surface of the center rod 202 is fixedly installed with the center ring 207, the inner end of the center ring 207 is rotatably installed with the driving cylinder 209, the end, away from the center rod 202, of the center ring 207 is fixedly installed with the supporting disc 208, and the outer surface of the supporting disc 208 is slidably installed with a plurality of locking blocks 206, the locking blocks 206 are arranged in a ring shape and are in contact with the outer surface of the sealing plug 205.

[0046] Specifically, the center of the sealing plug 205 is concave, so when the locking blocks 206 move towards the center, the sealing plug 205 moves in the direction of the center ring 207 under the action of pressure, and at this time, the locking blocks 206 are located at the center of the concave center of the sealing plug 205.

[0047] The inner end of the driving cylinder 209 is rotatably installed with a plurality of pulling rods 210, and the end, away from the driving cylinder 209, of the pulling rod 210 is rotatably connected with the outer surface of the locking block 206, in the default state, the pulling rod 210 is horizontally connected with the locking block 206, when the driving cylinder 209 moves in any rotating direction, the locking block 206 can be driven to move in the center direction of the supporting disc 208 through the pulling rod 210, and the outer surface of the driving cylinder 209 is rotatably installed with the passive rod 203 through a rotating shaft, the passive rod 203 is rotatably connected with the bottom end of the locking rod 302.

[0048] The working principle of the present application is as follows:

[0049] When working, the natural gas passes through the valve pipe 201 inside the valve body 1, under normal circumstances, the fluid pressure drives the pressure plug 304 to have an upward trend, at the same time, the reverse force is generated between the sealing sleeve 106 and the air column 102, and the two form a mechanical balance state, when the natural gas appears under-pressure in the flowing process, the pressure inside the air column 102 pushes the sealing sleeve 106 to move downward, and when the overpressure condition occurs, the pressure plug 304 moves upward and drives the sealing sleeve 106 to move upward through the supporting plate 108.

[0050] During the pressure fluctuation of natural gas, the displacement of pressure plug 304 is transmitted to the locking ring 107, only causing a slight fluctuation of the locking ring 107, and the fluctuation amplitude is designed to be controlled to ensure that the displacement of the pressure block 410 is not enough to reach the end position of the locking ring 107 (by customizing the parameters of the locking ring 107, the pressure fluctuation tolerance of the device can be optimized);

[0051] When the pressure of natural gas is too large or too small, the displacement of the locking ring 107 is too large, and the pressure block 410 moves to the end of the locking ring 107 under the elastic force of the reset spring 413, and the limiting rod 411 moves away from the lifting rod 403, at this time, the trigger spring 402 drives the push ring 404 to move upward under the elastic force, and promotes the lifting rod 403 to rotate, and then in the process of rotating the lifting rod 403, the sliding block 405 converges to the center of the guide rail 406, and promotes the passive plug 104 to move upward, because the passive plug 104 moves upward, the gas column 102 also moves upward, and in the process of moving the gas column 102, the locking rod 302 is pulled to move through the through pipe 105;

[0052] In the process of moving the locking rod 302, the passive rod 203 is driven to rotate the driving cylinder 209, and the locking block 206 converges to the center of the support disc 208 under the pulling of the pulling rod 210, at this time, the sealing plug 205 moves to the center of the valve pipe 201 under the pressure of natural gas, and finally cuts off the flow of natural gas.

[0053] When resetting, the top end of the gas column 102 is pressed while the reset cylinder 101 is lifted upward, and the cooperating ring 408 moves to the guide rail 406 direction under the driving force, and the auxiliary push block 407 pushes the sliding block 405 to displace through the cooperation of the inclined surface of the auxiliary push block 407 and the sliding block 405, and in the process of moving the reset cylinder 101, the center cylinder 401 is moved through the support frame 103, and the upper end of the lifting rod 403 in the inclined state is restored to the initial state along the guide rail 406;

[0054] Then the reset cylinder 101 and the gas column 102 are pressed downward to restore to the initial state, and the locking rod 302 also moves downward and drives the driving cylinder 209 to rotate, so that the locking block 206 moves out of the recess in the center of the passive plug 104, and the passive plug 104 returns to the initial position under the action of the force, and natural gas can continue to flow at this time.

[0055] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can make equivalent replacement or change within the technical range disclosed by the present application according to the technical scheme and the inventive concept of the present application, which should be covered within the protection scope of the present application.

Claims

1. A natural gas emergency shut-off valve, comprising a valve body (1), characterized in that: A fastening cover (2) is detachably installed on the upper end of the valve body (1). A reset cylinder (101) is inserted through the inner end of the fastening cover (2). A valve tube (201) is fixedly installed on the inner end of the valve body (1). The reset cylinder (101) is located above the valve tube (201). A support rod (204) is fixedly connected to the inner left end of the valve tube (201). A sealing plug (205) is inserted through the outer surface of the support rod (204). A cutting device is provided inside the reset cylinder (101). For detecting abnormal gas flow, the inner end of the reset cylinder (101) is provided with an air column (102). When the cut-off device is triggered, the air column (102) moves upward. The outer surface of the valve pipe (201) is fixedly connected with a connecting pipe (301), and the input end of the connecting pipe (301) is provided inside the reset cylinder (101). The inner end of the connecting pipe (301) is provided with a central cylinder (401), and the outer surface of the central cylinder (401) is fixedly fitted with a guide frame (409). Multiple limiting rods (411) are provided through the inner end of the guide frame (409), and multiple lifting rods (403) are rotatably installed on the outer surface of the central cylinder (401). A pressure block (410) is fixedly connected to the end of the limiting rod (411) away from the guide frame (409). A sealing sleeve (106) is provided through the inner end of the air column (102), and a locking ring (107) is fixedly sleeved on the outer surface of the sealing sleeve (106). The pressure block (410) is in contact with the outer surface of the locking ring (107). The guide frame (409) has a limit slider (412) slidably installed at its inner end. The outer surface of the limit slider (412) is in contact with the outer surface of the lifting rod (403). The limit rod (411) is fixedly connected to the limit slider (412). The inner end of the connecting pipe (301) is fitted with a pressure plug (304). The outer surface of the pressure plug (304) is fitted with a locking rod (302). The upper end of the locking rod (302) is fixedly fitted with an isolation frame (305).

2. A natural gas emergency shut-off valve according to claim 1, characterized in that: The cutting device includes a support frame (103), which is fixedly installed on the inner end of the reset cylinder (101) and is fixedly connected to the central cylinder (401).

3. A natural gas emergency shut-off valve according to claim 2, characterized in that: A passive plug (104) is fixedly installed at one end of the air column (102) near the connecting pipe (301). The passive plug (104) passes through the inner end of the reset cylinder (101). Multiple lifting rods (403) are arranged in a ring, and the free ends of each lifting rod (403) point to the bottom end of the passive plug (104).

4. A natural gas emergency shut-off valve according to claim 3, characterized in that: The passive plug (104) is provided with a guide rail (406) on the side near the lifting rod (403). The lifting rod (403) is rotatably mounted with a sliding block (405) at the end near the passive plug (104), and the sliding block (405) is slidably connected to the guide rail (406). When the lifting rod (403) rotates, its ends converge toward the end that is close to each other, and the guide rail (406) moves upward under this action.

5. A natural gas emergency shut-off valve according to claim 4, characterized in that: The reset cylinder (101) is provided with a push ring (404) inside. The push ring (404) is sleeved on the outside of multiple lifting rods (403). The push ring (404) and the reset cylinder (101) are connected by a trigger spring (402). Under the action of the elastic force of the trigger spring (402), the push ring (404) is always subjected to an upward force.

6. A natural gas emergency shut-off valve according to claim 2, characterized in that: A guide tube (105) is fixedly installed at the inner end of the air column (102), and the guide tube (105) passes through the inside of the sealing sleeve (106). A support plate (108) is fixedly connected to one end of the guide tube (105) away from the air column (102), and the support plate (108) is fixedly connected to the central cylinder (401).

7. A natural gas emergency shut-off valve according to claim 6, characterized in that: The guide frame (409) is parallel to the locking ring (107), and a guide groove is formed on the outer periphery of the guide frame (409).

8. A natural gas emergency shut-off valve according to claim 1, characterized in that: A central rod (202) is fixedly installed at the inner end of the valve tube (201). The central rod (202) corresponds to the support rod (204). A central ring (207) is fixedly installed on the outer surface of the central rod (202). A driving cylinder (209) is rotatably installed at the inner end of the central ring (207). A support plate (208) is fixedly installed at the end of the central ring (207) away from the central rod (202). A plurality of locking blocks (206) are slidably installed on the outer surface of the support plate (208). The locking blocks (206) are arranged in a ring shape and contact the outer surface of the sealing plug (205).

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