A pipeline self-closing valve for automatic pipeline closing

Abstract

The present invention discloses a pipeline self-closing valve for automatic pipeline closing. A valve core is arranged in a valve body. The valve core includes a sealing compression spring, a sealing shaft, a sealing gasket and a sliding cone body installed in the valve body. A sealing through hole is provided in the valve body. The sealing shaft passes through the sealing through hole and there is a gap between them. The first end of the sealing shaft is fixedly connected to one side of the sealing gasket, and the other side of the sealing gasket is connected to one end of the sealing compression spring. The small end of the sliding cone body with a conical circumferential surface is fixedly connected to the first end of the valve rod. The axial direction of the sliding cone body is the same as that of the valve rod and is perpendicular to the axial direction of the sealing shaft. The second end of the sealing shaft can contact the conical circumferential surface of the sliding cone body. The present invention utilizes the cooperation between the conical circumferential surface of the sliding cone body and the sealing shaft to make the linear motion of the sliding cone body and the linear motion of the sealing shaft coordinate and act synchronously, and finally realizes the purpose of automatically closing the valve and manually opening the valve under the conditions of low gas pressure (including loss of pressure) and overpressure.

Description

Technical Field

[0001] The present invention relates to a pipeline self-closing valve installed on a gas pipeline, and particularly to a pipeline self-closing valve for automatically closing a pipeline. Background Art

[0002] The pipeline self-closing valve, abbreviated as self-closing valve, is installed on the pipeline of a low-pressure gas system. When the gas supply pressure in the pipeline is underpressure or overpressure, without electricity or other external power, the pipeline self-closing valve can automatically close and must be manually opened. The pipeline self-closing valve installed at the connection between the end of the pipeline behind the gas meter and the rubber hose should have the function of closing under pressure loss.

[0003] The basic structure of most pipeline self-closing valves includes a valve body, a valve core, a valve stem, a fixing plate, a valve cover, a handle, a pull shaft, a sealing diaphragm and a magnet. Among them, the fixing plate, the valve cover and the sealing diaphragm are all installed on the valve body, the handle is installed on the valve cover, the handle is connected to the sealing diaphragm through the pull shaft, both ends of the valve stem are connected to the magnet and the valve core respectively, the magnet and the pull shaft are attracted by magnetic force, and there is also a suction force between the magnet and the fixing plate at the same time. The valve core and the valve stem have an elastic stress in the direction away from the handle (this elastic stress includes the stress generated by the spring and the magnet) and this stress changes with the position of the valve core; its basic working principle is: when the pipeline self-closing valve is in the closed state, the magnet and the pull shaft are separated; when manually opening the pipeline self-closing valve, first press the handle towards the direction close to the valve core to overcome the stress of the sealing diaphragm, so that the pull shaft is attracted to the magnet, and then lift the handle away from the valve core, driving the valve stem and the valve core to gradually move synchronously against the elastic stress until the pipeline self-closing valve is opened. During this process, gas gradually enters the valve body and generates a supporting force on the valve core. Finally, the valve core remains in a suspended state under the supporting force of the gas and keeps the pipeline self-closing valve in the open state; when the gas is underpressure or pressure loss, the elastic stress of the valve core is greater than the magnetic force and the gas supporting force in the opposite direction received by the valve stem, and the valve core and the valve stem move away from the handle until the magnet and the pull shaft are separated and the pipeline self-closing valve is closed, realizing the function of automatically closing the valve; when the gas is overpressure, the gas pressure overcomes the stress of the sealing diaphragm and makes the pull shaft move away from the valve core until the pull shaft is separated from the magnet. At this time, the elastic stress of the valve core is greater than the gas supporting force in the opposite direction received by the valve stem, and the valve core and the valve stem move away from the handle until the magnet and the pull shaft are separated and the pipeline self-closing valve is closed, realizing the function of automatically closing the valve. In this way, the automatic closing function of the pipeline self-closing valve under underpressure (including pressure loss) and overpressure can be realized.

[0004] On the premise of ensuring relatively high automatic closing sensitivity, the valve core structure of traditional pipeline gas valves is very complex, with relatively high manufacturing and assembly costs. Moreover, the more parts there are, the greater the likelihood of failure, and subsequent maintenance is also more difficult, which is not conducive to the functional improvement, service life extension, and popularization and application of pipeline self-closing valves. In addition, the sealing diaphragm and the pull shaft of traditional pipeline gas valves are fixedly connected by nuts, which may cause loosening after long-term use and affect the control accuracy of self-closing valves; the switch display structure of the gas switch of traditional pipeline gas valves has many and complex parts, increasing the product cost. Summary of the Invention

[0005] The purpose of the present invention is to provide a pipeline self-closing valve for pipeline automatic closing with a simple valve core structure, reliable valve closing performance, and long service life in order to solve the above problems.

[0006] The present invention achieves the above purpose through the following technical solutions:

[0007] A pipeline self-closing valve for pipeline automatic closing, comprising a valve body, a valve core, a valve rod, a magnet, a valve cover, a handle, a pull shaft, a sealing diaphragm, and a fixed disk. The valve core is arranged in the valve body. The first end of the valve rod is connected to the valve core. The circumferences of the valve cover, the fixed disk, and the sealing diaphragm are all installed on the valve body. The handle is installed on the valve cover. The handle is connected to the middle of the sealing diaphragm through the pull shaft. The second end of the valve rod passes through the central through hole of the fixed disk and is connected to the magnet. The magnet can attract the pull shaft and at the same time has a suction force with the fixed disk. The fixed disk is provided with a gas passing through hole for gas to pass through. The valve core includes a sealing compression spring, a sealing shaft, a sealing gasket, and a sliding cone installed in the valve body. A sealing through hole is provided in the valve body. The sealing shaft passes through the sealing through hole. A gap for gas to pass through is provided between the sealing shaft and the hole wall of the sealing through hole. The first end of the sealing shaft is fixedly connected to one side of the sealing gasket, and the sealing gasket can be in sealed contact connection with one end of the sealing through hole. The other side of the sealing gasket is connected to one end of the sealing compression spring. The small end of the sliding cone with a conical circumferential surface is fixedly connected to the first end of the valve rod. The axial direction of the sliding cone is the same as the axial direction of the valve rod and is perpendicular to the axial direction of the sealing shaft. The second end of the sealing shaft can contact the conical circumferential surface of the sliding cone.

[0008] In the above structure, the sealing compression spring generates an elastic force on the sealing gasket and the sealing shaft, so that the second end of the sealing shaft has a stress to press the sliding cone. At the same time, the sealing shaft and the sealing gasket cooperate to achieve the sealing contact and separation between the sealing gasket and one end of the sealing through hole when the sealing shaft moves, that is, to realize the closing and opening functions of the pipeline self-closing valve; the conical circumferential surface of the sliding cone cooperates with the second end of the sealing shaft, so that the linear motion of the sealing shaft and the linear motion of the sliding cone synchronously with the valve stem are coordinated and synchronized. The linkage between two linear motions perpendicular to each other is skillfully realized by using the sliding cone. Finally, the purpose of automatically closing the valve and manually opening the valve under gas underpressure (including pressure loss) and overpressure is achieved by cooperating with components such as the valve stem, magnet, pull shaft, sealing diaphragm and fixed plate; parameters such as the material, taper, length, and roughness of the sliding cone are determined according to actual needs.

[0009] Preferably, in order to improve the transmission stability and simplify the assembly process, the valve stem and the sliding cone are integrally formed.

[0010] Furthermore, in order to ensure that the valve stem can move accurately, a limiting convex column is provided at a position corresponding to the sliding cone in the valve body, a limiting counterbore is provided on the limiting convex column, and the first end of the valve stem passes through the large end of the sliding cone and is placed in the limiting counterbore.

[0011] Preferably, in order to save materials and improve the stability of the gas generating a supporting force on the sliding cone, a conical inner cavity is provided in the sliding cone, and the first end of the valve stem passes through the conical inner cavity.

[0012] Preferably, in order to make the contact transmission between the sealing shaft and the sliding cone smoother to reduce the transmission loss, a spherical convex column for contacting the sliding cone is provided at the second end of the sealing shaft.

[0013] Preferably, in order to make the connection between the pull shaft and the sealing diaphragm more stable and reliable to avoid the problem of loosening affecting the control accuracy, one end of the pull shaft for connecting with the sealing diaphragm is provided with a pull shaft cap with a larger outer diameter. The sealing diaphragm is sleeved on the pull shaft through its central through hole. A pressing plate is also sleeved on the pull shaft. The sealing diaphragm is located between the pull shaft cap and the pressing plate, and the pressing plate is tightly fixed by a pressing cap sleeved on the pull shaft.

[0014] Preferably, the compression cap is of an annular structure and is in interference connection with the outer wall of the pull shaft; a position near the edge of the sealing diaphragm bulges towards the direction of the handle to form an annular groove with a depth of 5-20 mm, and the edge part of the sealing diaphragm extends 5-20 mm towards the direction of the fixed disk compared with the central part. The interference connection between the compression cap and the pull shaft is a one-time press-fitting method, which is difficult to disassemble after one processing and has high stability; the design of the annular groove and the edge part of the sealing diaphragm can improve the elasticity and reset stress of the sealing diaphragm, which is beneficial to improving the valve closing control accuracy and the valve opening reset ability.

[0015] Furthermore, in order to facilitate the installation of the magnet and at the same time to adjust the magnitude of the gravitational force between the fixed disk and the magnet, the magnet is annular, and an annular magnetic isolation sheet is installed on the surface of the magnet near the fixed disk. The countersunk screw passes through the central through hole of the magnet and the central through hole of the magnetic isolation sheet in sequence and then is connected to the second end of the valve stem.

[0016] Furthermore, a gas switch is installed on the gas pipeline body at one end of the valve body, and an integrally formed and mutually perpendicular installation pipe body is communicated on the gas pipeline body. The switch valve stem of the gas switch passes through the installation pipe body and is connected to the switch handle. A switch indicating piece is fixedly installed at the port position of the installation pipe body. A switch mark is provided on the switch indicating piece. A handle cover is integrally formed on the switch handle. The handle cover presses the switch indicating piece. An observation through hole is provided on the handle cover. When the handle cover rotates, the observation through hole can correspond to the switch mark on the switch indicating piece. The above-mentioned switch indicating piece and handle cover cooperate to realize the switch indication function with a simple and practical structure.

[0017] Preferably, in order to realize the function of fixing the switch indicating piece so that it cannot rotate with a simple structure, one or more outwardly protruding rib strips are provided on the circumferential outer wall of the installation pipe body. The switch indicating piece is sleeved on the installation pipe body through its own through hole. The switch indicating piece is provided with a plurality of convex blocks, and each convex block is located between two adjacent outwardly protruding rib strips.

[0018] The beneficial effects of the present invention are as follows:

[0019] The present invention provides a valve core which is mainly composed of a sealing compression spring, a sealing shaft, a sealing pad and a sliding cone, and utilizes the conical circumferential surface of the sliding cone to cooperate with the sealing shaft so that the linear motion of the sliding cone and the linear motion of the sealing shaft are coordinated and act synchronously, thereby ultimately achieving the purpose of automatic valve closing and manual valve opening when the gas is under-pressure (including loss of pressure) and over-pressure. While ensuring high accuracy of automatic valve closing, the number of valve core parts is significantly reduced, the connection structure of each part is simplified, and the manufacturing and assembly costs are significantly reduced. In addition, due to the reduction in parts, the probability of failure is reduced, making later maintenance simpler and easier, which is beneficial to the improvement of the function, extension of the service life and promotion and application of pipeline self-closing valves. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a front sectional view of the pipeline self-closing valve for automatically closing a pipeline according to the present invention;

[0021] Figure 2 It is a top view of the pipeline self-closing valve for automatically closing a pipeline according to the present invention;

[0022] Figure 3 This is a front cross-sectional view of the sealing diaphragm and related parts of the pipeline self-closing valve for automatic pipeline closing according to the present invention, and the scale of the figure is larger than Figure 1 . DETAILED DESCRIPTION

[0023] The present invention will be further described below in conjunction with the accompanying drawings:

[0024] like Figure 1 and Figure 2 As shown, the pipeline self-closing valve for automatic pipeline closing of the present invention comprises a valve body 1, a valve core, a valve stem 27, a magnet 15, a valve cover 6, a handle 10, a pull shaft 11, a sealing diaphragm 7 and a fixed disk 8, wherein the valve core is arranged in the valve body 1, and the first end ( Figure 1 The lower end of the valve stem 27 is connected to the valve core, the circumferential edge of the valve cover 6, the circumferential edge of the fixed disk 8 and the circumferential edge of the sealing diaphragm 7 are all installed on the valve body 1, the handle 10 is installed on the valve cover 6 and can move, and the handle 10 is connected to the middle of the sealing diaphragm 7 through the pull shaft 11. The second end of the valve stem 27 ( Figure 1 The upper end of the valve body 1) passes through the central through hole of the fixed disk 8 and is connected to the magnet 15. The magnet 15 can be combined with the pull shaft 11 and has suction force with the fixed disk 8 at the same time. The fixed disk 8 is provided with a gas through hole 30 for the gas to pass through. The gas through hole 30 is preferably a circular through hole. The valve core includes a sealing compression spring 3, a sealing shaft 5, a sealing gasket 4 and a sliding cone 29 installed in the valve body 1. The valve body 1 is provided with a sealing through hole (not marked in the figure). The sealing shaft 5 passes through the sealing through hole. A gap for the gas to pass through is provided between the sealing shaft 5 and the hole wall of the sealing through hole (not visible in the figure). The first end of the sealing shaft 5 (Figure 1 The left end (in the left end of []) is fixedly connected to one side of the sealing gasket 4, and the sealing gasket 4 can be in sealing contact connection with one end of the sealing through hole. The other side of the sealing gasket 4 is connected to one end of the sealing compression spring 3. The small end ( Figure 1 the upper end in []) is fixedly connected to the first end of the valve stem 27. The axial direction ( Figure 1 the vertical direction in []) of the sliding cone 29 is the same as the axial direction of the valve stem 27 and is perpendicular to the axial direction ( Figure 1 the transverse direction in []) of the sealing shaft 5. The second end ( Figure 1 the right end in []) of the sealing shaft 5 can contact the conical circumferential surface of the sliding cone 29.

[0025] Figure 1 Also shown in [] is a filter and flow-limiting device 2 provided in the intake end of the valve body 1. Figure 1 and Figure 2 Also shown in [] is a handle housing 12 connected to the valve cover 6 and used in cooperation with the handle 10, and a pipe joint 23 connected to the outlet end of the valve body 1. These are all conventional self-closing valve structures.

[0026] Such as Figure 1 and Figure 2As shown, before use, the pipeline self-closing valve is in a closed state, that is, the sliding cone 29 is at the position farthest from the handle 10. At this time, the second end of the sealing shaft 5 contacts the upper part of the sliding cone 29, and the sealing gasket 4 is in close contact with one end of the sealing through-hole to achieve a sealed connection. Gas cannot pass through the sealing through-hole. At the same time, the pull shaft 11 and the magnet 15 are in a separated state. When it is necessary to open the pipeline self-closing valve, a manual valve-opening method is adopted. First, press the handle 10 in the direction close to the sliding cone 29 with the hand until the pull shaft 11 and the magnet 15 are attracted together. Then, lift the handle 10 in the direction away from the sliding cone 29. Since the sealing compression spring is in a relatively extended state at this time and the pressure on the sliding cone 29 is small, the sliding cone 29 can be smoothly lifted by the suction force between the pull shaft 11 and the magnet 15. During this process, the sealing gasket 4 gradually separates from one end of the sealing through-hole, and gas begins to enter the valve body 1 through the sealing through-hole and fills the space where the sliding cone 29 is located. Since the gas is a high-pressure gas, its pressure will generate a supporting force on the sliding cone 29, causing it to move in the direction close to the handle 10. As the sliding cone 29 and the sealing shaft 5 continue to move, the pressure of the sealing compression spring 3 on the sliding cone 29 becomes larger and larger, the gas flow rate also becomes larger and larger, and the supporting force of the gas on the sliding cone 29 also becomes larger and larger. At the same time, the suction force of the fixed disk 8 on the magnet 15 becomes smaller and smaller. The combined change of these several forces will maintain the suction state between the pull shaft 11 and the magnet 15 until the sliding cone 29 moves to the limit position and the pipeline self-closing valve is fully opened, completing the valve-opening operation. After that, the gas passes normally under normal pressure, and the sliding cone 29 maintains a suspended state, and the pipeline self-closing valve will not act. At this time, the sum of the pressure of the sealing compression spring 3 on the sliding cone 29 and the pressure generated by the suction force of the fixed disk 8 on the magnet 15 is basically equal to the sum of the supporting force of the gas on the sliding cone 29 and the pulling force of the stress of the sealing diaphragm 7 on the sliding cone 29, so it maintains a quasi-steady state.

[0027] When the gas pressure is underpressure or loss of pressure, the supporting force of the gas on the sliding cone 29 decreases. The sum of the pressure of the sealing compression spring 3 on the sliding cone 29 and the pressure generated by the suction force of the fixed disk 8 on the magnet 15 is greater than the sum of the supporting force of the gas on the sliding cone 29 and the pulling force of the stress of the sealing diaphragm 7 on the sliding cone 29. The sliding cone 29 will move in the direction away from the handle 10. This movement makes the pressure generated by the suction force of the fixed disk 8 on the magnet 15 larger and larger, makes the supporting force of the gas on the sliding cone 29 smaller and smaller, makes the pressure of the sealing compression spring 3 on the sliding cone 29 smaller and smaller, and makes the pulling force of the stress of the sealing diaphragm 7 on the sliding cone 29 larger and larger. The combined result of these several forces is to make the sliding cone 29 continue to move until the pipeline self-closing valve is fully closed, realizing the function of automatically closing the pipeline self-closing valve when the gas is underpressure or loss of pressure.

[0028] When the gas pressure exceeds the rated pressure, the supporting force of the gas on the sliding cone 29 increases. However, since the sliding cone 29 is blocked by the fixed disk 8, it cannot continue to move towards the handle 10. At this time, the overpressure gas enters the lower part of the sealing diaphragm 7 through the gas passage hole 30 on the fixed disk 8, and the pressure on the sealing diaphragm 7 exceeds its own stress, causing the sealing diaphragm 7 to move towards the handle 10 and driving the pull shaft 11 to move synchronously. Since the magnet 15 cannot move along, the pull shaft 11 and the magnet 15 will separate. After separation, since the stress of the sealing diaphragm 7 is no longer applied, the pulling force on the sliding cone 29 will be much smaller. The sum of the pressure of the sealing compression spring 3 on the sliding cone 29 and the suction force of the fixed disk 8 on the magnet 15 will be greater than the supporting force of the gas on the sliding cone 29, causing the sliding cone 29 to move away from the handle 10 until the pipeline self-closing valve is completely closed, realizing the function of automatically closing the pipeline self-closing valve when the gas pressure exceeds the rated pressure.

[0029] As Figure 1 、 Figure 2 and Figure 3 shown, the present invention also discloses the following various more optimized specific structures. According to actual needs, the above structure can be superimposed and combined with one or more of the following structures to form a more optimized technical solution.

[0030] To improve the transmission stability and simplify the assembly process, the valve stem 27 and the sliding cone 29 are integrally formed, which is not only convenient for processing and assembly but also can improve the connection strength and transmission accuracy.

[0031] To ensure that the valve stem 27 can move precisely, a limiting convex column 24 is provided at the position corresponding to the sliding cone 29 in the valve body 1, and a limiting counterbore 25 is provided on the limiting convex column 24. The first end of the valve stem 27 passes through the large end of the sliding cone 29 and is placed in the limiting counterbore 25. The first end of the valve stem 27 is limited in motion, increasing the stability and accuracy of the movement of the valve stem 27 and the sliding cone 29, making the valve opening and closing more reliable.

[0032] To save materials and improve the stability of the supporting force generated by the gas on the sliding cone 29, a conical inner cavity 28 is provided in the sliding cone 29, and the first end of the valve stem 27 passes through the conical inner cavity 28.

[0033] To make the contact transmission between the sealing shaft 5 and the sliding cone 29 smoother to reduce transmission loss, a spherical convex column (not marked in the figure) for contacting the sliding cone 29 is provided at the second end of the sealing shaft 5. The contact friction between the spherical surface and the conical surface is smaller, and the sliding is smoother.

[0034] In order to make the connection between the drawbar 11 and the sealing diaphragm 7 more stable and reliable to avoid the problem that loosening affects the control accuracy, one end of the drawbar 11 for connecting with the sealing diaphragm 7 is provided with a drawbar cap 14 with a larger outer diameter. The sealing diaphragm 7 is sleeved on the drawbar 11 through its central through hole. A pressing plate 9 is also sleeved on the drawbar 11. The sealing diaphragm 7 is located between the drawbar cap 14 and the pressing plate 9, and the pressing plate 9 is tightly fixed by a compression cap 13 sleeved on the drawbar 11; the compression cap 13 is of an annular structure and there is an interference connection between its inner wall and the outer wall of the drawbar 11; at a position near the edge of the sealing diaphragm 7, it bulges towards the direction close to the handle 10 to form an annular groove 32 with a depth of 5 - 20 mm, and the edge part 33 of the sealing diaphragm 7 extends 5 - 20 mm towards the direction close to the fixed disk 8 compared with the central part. The interference connection between the compression cap 13 and the drawbar 11 is a one-time pressing connection method, which is very difficult to disassemble after one processing and has high stability; the design of the annular groove 32 and the edge part 33 of the sealing diaphragm 7 can improve the elasticity and reset stress of the sealing diaphragm 7, which is beneficial to improving the valve closing control accuracy and the valve opening reset ability.

[0035] In order to facilitate the installation of the magnet 15 and at the same time to adjust the magnitude of the gravitational force between the fixed disk 8 and the magnet 15, the magnet 15 is annular, and an annular magnetic isolation sheet 16 is installed on the surface of the magnet 15 near the fixed disk 8. The countersunk screw 26 passes through the central through holes of the magnet 15 and the magnetic isolation sheet 16 in sequence and then is connected to the second end of the valve stem 27.

[0036] A gas switch is installed on the gas pipe body at one end (the gas outlet end in the figure) of the valve body 1, and an integrally formed and mutually perpendicular installation pipe body 21 is communicated with the gas pipe body. The switch valve stem 19 of the gas switch passes through the installation pipe body 21 and is connected to the switch handle 17. A switch indicating piece 20 is fixedly installed at the port position of the installation pipe body 21. The switch indicating piece 20 is provided with switch markings (i.e., the words "open" and "close"). A handle cover 18 is integrally formed on the switch handle 17. The handle cover 18 presses the switch indicating piece 20. An observation through hole 31 is provided on the handle cover 18, and when the handle cover 18 rotates, the observation through hole 31 can correspond to the switch markings on the switch indicating piece 20. The above-mentioned switch indicating piece 20 and the handle cover 18 cooperate to realize the switch indication function with a simple and practical structure.

[0037] In order to realize the function of fixing the switch indicating piece 20 so that it cannot rotate with a simple structure, one or more outwardly protruding rib strips (not marked in the figure) are provided on the circumferential outer wall of the installation pipe body 21. The switch indicating piece 20 is sleeved on the installation pipe body 21 through its through hole, and the switch indicating piece 20 is provided with a plurality of convex blocks (not marked in the figure), and each of the convex blocks is located between two adjacent outwardly protruding rib strips. Such a limiting structure is simple and practical.

[0038] Figure 1Also shown in the figure is the ball valve core 22 of the gas switch, which is connected to the switch valve stem 19 to achieve the switching function.

[0039] The above embodiments are only preferred embodiments of the present invention and do not limit the technical solutions of the present invention. Any technical solution that can be achieved on the basis of the above embodiments without creative labor shall be regarded as falling within the scope of the patent rights of the present invention.

Claims

1. A pipeline self - closing valve for automatic pipeline closing, comprising a valve body, a valve core, a valve stem, a magnet, a valve cover, a handle, a pull shaft, a sealing diaphragm and a fixing plate. The valve core is arranged in the valve body. The first end of the valve stem is connected to the valve core. The circumferences of the valve cover, the fixing plate and the sealing diaphragm are all installed on the valve body. The handle is installed on the valve cover. The handle is connected to the middle part of the sealing diaphragm through the pull shaft. The second end of the valve stem passes through the central through - hole of the fixing plate and is connected to the magnet. The magnet can attract and engage with the pull shaft and at the same time has a suction force with the fixing plate. The fixing plate is provided with a gas - passing through - hole for gas to pass through. Characterized in that: The valve core includes a sealing compression spring, a sealing shaft, a sealing gasket and a sliding cone installed in the valve body. There is a sealing through - hole in the valve body. The sealing shaft passes through the sealing through - hole. There is a gap for gas to pass through between the sealing shaft and the hole wall of the sealing through - hole. The first end of the sealing shaft is fixedly connected to one side of the sealing gasket, and the sealing gasket can be in sealing contact connection with one end of the sealing through - hole. The other side of the sealing gasket is connected to one end of the sealing compression spring. The small end of the sliding cone with a conical circumferential surface is fixedly connected to the first end of the valve stem. The axial direction of the sliding cone is the same as the axial direction of the valve stem and is perpendicular to the axial direction of the sealing shaft. The second end of the sealing shaft can contact the conical circumferential surface of the sliding cone. One end of the pull shaft for connecting with the sealing diaphragm is provided with a pull - shaft cap with a larger outer diameter. The sealing diaphragm is sleeved on the pull shaft through its central through - hole. A pressing plate is also sleeved on the pull shaft. The sealing diaphragm is located between the pull - shaft cap and the pressing plate. The pressing plate is fixedly pressed by a pressing cap sleeved on the pull shaft. The magnet is annular. An annular magnetic isolation sheet is installed on the surface of the magnet close to the fixing plate. The countersunk head screw passes through the central through - hole of the magnet and the central through - hole of the magnetic isolation sheet in sequence and then is connected to the second end of the valve stem.

2. The pipeline self - closing valve for automatic pipeline closing according to claim 1, Characterized in that: The valve stem and the sliding cone are integrally formed.

3. The pipeline self - closing valve for automatic pipeline closing according to claim 2, Characterized in that: A limiting convex column is arranged at a position corresponding to the sliding cone in the valve body. A limiting counterbore is arranged on the limiting convex column. The first end of the valve stem passes through the large end of the sliding cone and is placed in the limiting counterbore.

4. The pipeline self - closing valve for automatic pipeline closing according to claim 3, Characterized in that: A conical inner cavity is arranged in the sliding cone. The first end of the valve stem passes through the conical inner cavity.

5. The pipeline self - closing valve for automatic pipeline closing according to claim 1, Characterized in that: The second end of the sealing shaft is provided with a spherical convex column for contacting the sliding cone.

6. The pipeline self - closing valve for automatic pipeline closing according to claim 1, Characterized in that: The compression cap has an annular structure and is in interference connection with the outer wall of the pull shaft; a position near the edge of the sealing diaphragm bulges towards the handle to form an annular groove with a depth of 5-20 mm, and the edge part of the sealing diaphragm extends 5-20 mm towards the fixed disk compared with the central part.

7. The pipeline self-closing valve for automatic pipeline closing according to any one of claims 1-5, characterized in that: a gas switch is installed on the gas pipeline body at one end of the valve body, and an integrally formed and mutually perpendicular installation pipe body is communicated on the gas pipeline body. The switch valve rod of the gas switch passes through the installation pipe body and is connected with a switch handle. A switch indicating piece is fixedly installed at the port position of the installation pipe body. A switch mark is provided on the switch indicating piece. A handle cover is integrally formed on the switch handle. The handle cover presses the switch indicating piece. An observation through hole is provided on the handle cover. When the handle cover rotates, the observation through hole can correspond to the switch mark on the switch indicating piece.

8. The pipeline self-closing valve for automatic pipeline closing according to claim 7, characterized in that: one or more outwardly protruding rib strips are provided on the circumferential outer wall of the installation pipe body. The switch indicating piece is sleeved on the installation pipe body through its own through hole. The switch indicating piece is provided with a plurality of bumps, and each bump is located between two adjacent outwardly protruding rib strips.

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