Axial-flow type gas cut-off valve

Abstract

The invention relates to the technical field of cut-off valves, in particular to an axial flow type gas cut-off valve which comprises a valve body, a valve cylinder located in the valve body and a cut-off mechanism fixed to the valve body. The cut-off mechanism comprises a bottom plate, a reset mechanism, a swing hook and a trigger mechanism. A shifting fork is rotationally connected in the trigger mechanism, a rotary sleeve is rotationally connected in the reset mechanism, and a pin is vertically fixed on the rotary sleeve; the swing hook is horizontally arranged in the reset mechanism, a first torsional spring is arranged at a rotary connecting point of the swing hook, one end of the swing hook is a cutter tip end, the other end of the swing hook is a hook groove end, and a bayonet is formed in the hook groove end; the arc surface of the shifting fork is used for clamping the cutter tip end of the swing hook, and the pin is located in the bayonet of the hook groove end and can clamp the hook groove end; when the shifting fork rotates, the pin can be controlled to be separated from the swing hook bayonet. When a valve body medium is in an overpressure or decompression state, a passage can be quickly, efficiently and stably cut off, and stable operation of a transportation system is effectively guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of cut-off valves, in particular to an axial flow gas cut-off valve. Background Art

[0002] Axial flow gas shut-off valve is a valve specially used in gas pipeline systems. It can quickly cut off the gas flow in the pipeline in an emergency to ensure the pressure safety of the pipeline system. It is widely used in various industrial fields such as natural gas transmission systems, chemical plants, oil extraction, and urban gas pipeline networks.

[0003] The working principle of the axial flow gas shut-off valve can be simply understood as opening or closing the gas flow channel by controlling the position of the valve core. When the valve core is open, the gas can flow axially in the valve body; when the valve core is closed and locked, the valve core will block the gas flow, thereby cutting off the gas supply.

[0004] In practical applications, the shut-off valve should maintain high reliability to ensure that the gas supply can be quickly shut off in the event of a gas leak or other emergency. Especially when there is a leak of corrosive gas or flammable and explosive gas, the effectiveness and timeliness of the shut-off valve in cutting off the pipeline can reduce the industrial accident rate to a minimum, avoid unnecessary industrial disasters, and ensure the safety of production operations.

[0005] The prior art "A High-pressure Safety Cut-off Valve" (publication number: CN 113639054 A) discloses a valve body structure, which uses a transmission rod to push a bump wheel, so that the bump wheel pushes the first hook to swing, thereby separating the second hook from the first hook. When the second hook swings, the reset hook also separates from the second hook, so that the block on the valve stem is no longer restricted by the second hook, and the valve stem can move downward and block the opening of the pipeline, thereby cutting off the passage of the pipeline. However, the prior art still has the following technical problems:

[0006] The shut-off valve in the prior art adopts multiple transmission parts including a first pull hook, a second pull hook, a reset pull hook and a pull block for transmission control, and the connecting parts of these transmission parts are all hook-shaped, so the dimensional accuracy requirements of the hook-shaped parts are very high to ensure effective hooking and locking between the transmission parts. However, the hook-shaped parts are easily worn during the operation, and even slight wear will cause transmission failure. The number of transmission parts in the prior art is large, and wear of the hook-shaped parts on any one of the parts will cause the failure of the entire transmission chain. At the same time, the entire transmission mechanism is vertically arranged. Under the action of gravity, the upper part of the rotating pin of each transmission part is more worn, which will cause the position of the transmission part to sag easily, further causing the transmission effect of the transmission part to fail, the valve stem of the shut-off valve cannot move in time or even cannot move, and the passage of the pipeline cannot be cut off in time, thereby causing industrial disasters such as gas leakage. Summary of the invention

[0007] The present invention provides an axial flow gas shut-off valve, which can solve the problem that the transmission mechanism of the shut-off valve in the prior art is prone to structural failure, resulting in the valve stem being unable to cut off the pipeline passage in time, which is prone to cause industrial disasters such as gas leakage.

[0008] The present application provides the following technical solution: an axial flow gas shut-off valve, comprising a valve body, a valve cylinder slidably connected in the valve body, and a shut-off mechanism fixed on the valve body; the shut-off mechanism is used to control the axial movement of the valve cylinder in the valve body;

[0009] The cutting mechanism includes a bottom plate fixed on the valve body, a reset mechanism fixed on the bottom plate, a swing hook rotatably connected in the reset mechanism, and a trigger mechanism located on one side of the reset mechanism;

[0010] A shift fork is connected to the trigger mechanism for rotation in a vertical direction, and the cross section of the shift fork is semicircular. A rotary sleeve is connected to the reset mechanism for rotation in a vertical direction, and a pin is vertically fixed on the rotary sleeve.

[0011] The swing hook is horizontally arranged in the reset mechanism, and a torsion spring is arranged at the rotation connection point of the swing hook, one end of the swing hook is a knife tip, and the other end of the swing hook is a hook slot end, and a bayonet is arranged at the hook slot end;

[0012] The arc surface of the shift fork is used to clamp the tip of the swing hook, and the pin is located in the clamping mouth of the hook groove end and can clamp the hook groove end; when the shift fork rotates, the pin can be controlled to disengage from the clamping mouth of the swing hook.

[0013] Beneficial effects:

[0014] 1. High effectiveness and sensitivity. The prior art uses multiple hook-shaped transmission parts to trigger the action of the valve flap or valve cylinder by hooking and connecting them in sequence. However, the fatal problem of this structure is that as long as there is a problem with the hook structure of one transmission part, the entire transmission chain will fail. The present application uses a connection mechanism between a shift fork with a semicircular cross-section and a swing hook with a knife tip. The circular arc surface of the shift fork is used to clamp the knife tip of the swing hook. Therefore, as long as the shift fork is rotated to a certain angle, the knife tip of the swing hook will be able to separate from the circular arc surface of the shift fork, so that the swing hook triggers the swing action, and the trigger action will not fail. Compared with the prior art, this solution has higher effectiveness and sensitivity; it can enable the valve cylinder to close the pipeline channel in time.

[0015] 2. High reliability. The existing technology has a large number of transmission parts and adopts a multi-stage transmission method, which will lead to a higher failure rate. The main transmission part in this solution is a swing hook. The number of transmission parts is greatly reduced compared with the comparative documents, the mechanical structure is more streamlined, and it is less prone to mechanical failure. It is also conducive to the later replacement, repair and maintenance of parts, thereby improving the reliability of rapid pipeline disconnection.

[0016] 3. Long service life. The transmission parts in the prior art are all arranged vertically. Under the action of gravity, the upper part of the rotating pin of each transmission part is more worn, which makes the position of the transmission part easy to sag and cause the contact position of each transmission part to be misaligned, thus causing transmission failure. However, the swing hook of this scheme is arranged horizontally. When the swing hook swings and rotates, the rotating connection part is evenly stressed, and it is not easy to have excessive local wear, thereby effectively improving the service life.

[0017] Furthermore, the trigger mechanism includes a spring cavity fixed on the base plate, a piston cavity fixed on the spring cavity, a piston slidably connected in the piston cavity, a valve stem slidably connected in the spring cavity and a fork seat fixed in the spring cavity, and the fork is rotatably connected to the fork seat; a disc is fixedly provided on the rod portion of the valve stem, a pressure-loss cylinder is provided at one end of the valve stem away from the piston, the pressure-loss cylinder can slide axially in the spring cavity, a pressure-loss spring is provided inside the pressure-loss cylinder, and an overpressure spring is provided outside the pressure-loss cylinder.

[0018] Beneficial effect: The piston cavity can be connected with the air inlet side of the valve body, so as to detect the pressure of gas entering the valve body. When the pressure is too low or too high, the valve stem will move axially in the spring cavity and drive the pull fork to rotate, thereby triggering the valve cylinder in the valve body to seal the pipeline, thereby achieving the purpose of rapid response and realizing dual detection of gas decompression and overpressure, improving applicability, and the decompression spring and overpressure spring can ensure that the valve stem can be reset when the valve body pressure returns to normal, thereby improving the reliability of the trigger mechanism.

[0019] Furthermore, the tip of the swing hook is a sharp angle, and the angle of the sharp angle is 69°40′ to 70°20′.

[0020] Beneficial effect: When the pipeline is over-pressured or under-pressured, the shift fork will rotate under the action of the valve stem, so that the sharp corner of the tip of the swing hook will slide along the arc surface of the shift fork round rod, and the sharp corner is in point contact with the arc surface of the shift fork round rod, so that the shift fork will not be separated from the arc surface until it rotates to a certain angle, and it is not easy to separate prematurely, thereby improving the triggering accuracy, sensitivity and effectiveness of the triggering mechanism.

[0021] Furthermore, the shift fork comprises an integrally formed round rod, a round plate fixed above the round rod and a column fixed above the round plate, the column is arranged above the round plate close to the outer circle, and the middle rod portion of the round rod has a semicircular cross section.

[0022] Beneficial effect: When the gas pressure is underpressure or overpressure, the axial movement of the valve stem causes the disc on the valve stem to move the column, thereby driving the fork to rotate. The cross-section of the rod in the middle of the round rod of the fork is designed to be semicircular, which can facilitate the knife tip of the swing hook to smoothly and quickly disengage along the semicircular arc surface of the round rod when the fork rotates, thereby improving the response speed of the entire trigger action and improving the effectiveness and reliability of the trigger mechanism.

[0023] Furthermore, a notch is provided on the fork seat, and the middle rod portion of the round rod of the fork is located in the notch.

[0024] Beneficial effect: The notch on the fork seat enables the tip of the swing hook to extend into the notch and contact the middle rod of the fork round rod, so that the fork can clamp the tip of the swing hook, which helps to achieve precise control of the swing hook and ensure the rapid response and high reliability of the mechanical linkage of the trigger mechanism and the reset mechanism.

[0025] Furthermore, the reset mechanism includes a shell fixed on the base plate, a rotary sleeve rotatably connected to the shell, a turntable located below the rotary sleeve and a screw fixed to the bottom of the turntable, a through square hole is provided in the middle of the rotary sleeve, the turntable includes an integrally formed square rod and a connecting disk fixed below the square rod, the screw is vertically fixed to the bottom of the connecting disk near the outer circle, the upper part of the square rod extends into the square hole of the rotary sleeve, and the lower end of the square rod and the connecting disk are located in the valve body.

[0026] Beneficial effect: When gas overpressure or underpressure occurs at the air inlet end of the valve body, the pin on the rotary sleeve will be detached from the bayonet of the swing hook. The square hole on the rotary sleeve is for easy insertion of a wrench tool. When the wrench is turned, the pin can be driven to re-enter the bayonet at the hook groove end of the swing hook to achieve accurate resetting of the pin and ensure that the cutting mechanism can operate stably again.

[0027] Furthermore, the reset mechanism also includes a baffle fixed on the outer periphery of the valve cylinder and a sealing spring sleeved on the valve cylinder. The sealing spring is located in the space formed by the baffle and the inner cavity of the valve body. The screw at the bottom of the connecting plate is located on the side of the baffle away from the sealing spring.

[0028] Beneficial effect: The screw at the bottom of the connecting plate is used to tighten the baffle, so that the other side of the baffle compresses the sealing spring. The axial elastic force of the sealing spring is transmitted to the screw through the baffle, and then transmitted through the turntable and the rotary sleeve so that the pin on the rotary sleeve can be tightened in the bayonet of the swing hook, so that the reset mechanism and the trigger mechanism form a balance, which is beneficial when an overpressure or underpressure signal appears at the air inlet end of the valve body. The pin is disengaged from the bayonet of the swing hook, and the elastic force of the sealing spring can control the axial movement of the valve cylinder, so that the valve cylinder can quickly block the pipeline opening, with a fast response speed, thereby improving the effectiveness of pipeline passage cutting.

[0029] Furthermore, a valve seat is provided in the valve body, and a plurality of arc-shaped holes are evenly distributed along the circumference of the valve seat. A pressure cover is fixed at the center of the valve seat, and a valve disc is fixed between the valve seat and the pressure cover. The end face of the valve cylinder on the screw side can be pressed against the surface of the valve disc to seal the valve body.

[0030] Beneficial effect: The arc-shaped hole facilitates gas to enter the valve body from the air inlet end of the valve body, and flow into the air outlet end through the middle hole of the valve cylinder. The pressure cover is used to press the valve disc against the valve seat, and the end face of the valve cylinder is pressed against the surface of the valve disc, which can prevent gas from flowing into the middle hole of the valve cylinder, thereby forming a cutting effect on the pipeline passage, which helps to ensure the sealing of the plugging.

[0031] Furthermore, an O-ring is provided on the sliding connection surface between the valve body and the valve cylinder.

[0032] Beneficial effect: The O-ring is used to seal the gap between the valve body and the valve cylinder to prevent gas leakage from the gap between the valve body and the valve cylinder after the valve cylinder completes the sealing of the valve body pipeline, thereby improving the sealing performance of the valve cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a top view of the present invention.

[0034] Figure 2 for Figure 1 Cross-sectional view of DD.

[0035] Figure 3 for Figure 1 Front view of the middle housing, spring chamber and piston chamber.

[0036] Figure 4 for Figure 3 Sectional view of AA.

[0037] Figure 5 for Figure 3 Cross-sectional view of BB.

[0038] Figure 6 for Figure 3 Cross-sectional view of CC.

[0039] Figure 7 for Figure 5 Cross-sectional view of EE.

[0040] Figure 8 for Figure 5 Cross-sectional view of FF.

[0041] Fig. 9 This is a top view after the screws are installed on the bottom of the connection plate.

[0042] Fig.10 It is a schematic diagram of the principle of the pin disengaging from the swing hook bayonet. DETAILED DESCRIPTION

[0043] The following is further described in detail through specific implementation methods:

[0044] The marks in the drawings of the specification include: air inlet end 1, air outlet end 2, valve body 3, O-ring 4, valve cylinder 5, sealing spring 6, baffle 7, screw 8, mounting seat 9, base plate 10, shell 11, pin 12, rotary sleeve seat 13, turntable 14, square rod 141, connecting plate 142, pressure cover 15, valve disc 16, valve seat 17, positioning plate 18, balancing valve 19, observation port cover 20, spring cavity 21, disc 22, valve stem 23, column 24, round rod 25, swing hook 26, bayonet 27, locating pin 28, sharp corner 29, rotary sleeve 30, piston 31, piston cavity 32, fork seat 33, annular groove 331, pressure loss cylinder 34, pressure loss spring 35, overpressure spring 36, overpressure spring cover 37, pressure loss spring cover 38, round plate 39, and stop pin 40.

[0045] Embodiment 1

[0046] like Figures 1 to 10 As shown, an axial flow gas shut-off valve comprises Figure 2 The valve body 3, the valve cylinder 5 slidably connected in the valve body 3 and the cutting mechanism fixed on the valve body 3; the cutting mechanism is used to control the axial sliding of the valve cylinder 5 in the valve body 3.

[0047] like Figure 1 and Figure 2 As shown, a valve seat 17 is also fixed in the valve body 3, and a plurality of arc-shaped holes are evenly distributed on the valve seat 17 along the circumference (the shape of the entire valve seat 17 is similar to that of a car steering wheel, and the pipeline medium can flow through the arc-shaped holes), a gland 15 is fixed to the center thread of the valve seat 17, and a circular valve flap 16 is fixed between the valve seat 17 and the gland 15. The material of the valve flap 16 is preferably nitrile rubber. The gland 15 presses the valve flap 16 against the valve seat 17, and the outer circumferential diameter of the gland 15 is smaller than the inner hole diameter of the valve cylinder 5, and the outer circumferential diameter of the valve flap 16 is larger than the outer circumferential diameter of the valve cylinder 5, so that Figure 2 When the valve cylinder 5 slides to the left, the end face of the valve cylinder 5 can be fastened to the surface of the valve disc 16, and the arc hole on the valve seat 17 is close to the outer circumference of the valve seat 17. Therefore, when the end face of the valve cylinder 5 is fastened to the surface of the valve disc 16, the gas entering from the air inlet end 1 of the valve body 3 will be blocked by the valve cylinder 5; a positioning plate 18 is also installed in the valve body 3, and the outer circumference of the valve cylinder 5 is penetrated on the positioning plate 18, so that the positioning plate 18 can guide when the valve cylinder 5 moves axially, and the end of the valve cylinder 5 away from the valve seat 17 is slidably connected to the inner wall surface of the valve body 3, and the sliding connection surface of the valve body 3 and the valve cylinder 5 is provided with an O-ring 4, which is used to prevent the gas from leaking from the gap between the valve body 3 and the valve cylinder 5 after the end face of the valve cylinder 5 is fastened to the surface of the valve disc 16. The top of the valve body 3 is provided with an opening, and a mounting seat 9 is fixed in the opening, and a rotating sleeve seat 13 is fixed above the mounting seat 9.

[0048] The cutting mechanism comprises a base plate 10 threadedly fastened on a rotary sleeve seat 13, a reset mechanism fixed on the base plate 10, a swing hook 26 rotatably connected in the reset mechanism, and a trigger mechanism located at one side of the reset mechanism.

[0049] like Figure 2 As shown, the reset mechanism includes a housing 11 fixed on the base plate 10, a rotary sleeve 30 rotatably connected to the rotary sleeve seat 13, a turntable 14 located below the rotary sleeve 30, and a screw 8 fixed to the bottom of the turntable 14. A protrusion is provided in the middle of the rod of the rotary sleeve 30, and a pin 12 is fixed vertically downward on the protrusion. An observation port is provided at the top of the housing 11 above the rotary sleeve 30, and an observation port cover 20 is provided on the observation port. A through square hole is provided in the middle of the rotary sleeve 30. The observation port cover 20 can be opened and a wrench tool can be inserted into the square hole to pull and reset the rotary sleeve 30. The turntable 14 includes an integrally formed square rod 141 and a circular connecting disk 142 fixed below the square rod 141. The screw 8 is vertically fixed at the bottom of the connecting disk 142 near the outer circumference (such as Fig. 9 As shown in FIG. 1 , the upper part of the square rod 141 extends into the square hole of the rotary sleeve 30, and the lower end of the square rod 141 and the connecting plate 142 are located in the valve body 3. The reset mechanism also includes an annular baffle 7 fixed on the outer periphery of the valve cylinder 5 and a blocking spring 6 sleeved on the valve cylinder 5, and the blocking spring 6 is located in the space formed by the baffle 7 and the inner cavity of the valve body 3.

[0050] For ease of presentation, Figure 3 The view will Figure 1 The housing 11 and the structure connected to the housing 11 are rotated 180 degrees ( Figure 3 In the view of FIG. 1 , the base plate 10 is located at the bottom of the housing 11), as shown Figure 3 and 5 As shown, the trigger mechanism includes a spring cavity 21 fixed on the base plate 10, a piston cavity 32 fixed on the spring cavity 21, a piston 31 slidably connected in the piston cavity 32, a valve stem 23 slidably connected in the spring cavity 21, and a fork seat 33 fixed in the spring cavity 21, a notch is provided on the fork seat 33, and the opening of the notch faces the direction of the housing 11; a fork is rotatably connected to the fork seat 33; the fork includes an integrally formed round rod 25, a round plate 39 fixed above the round rod 25, and two columns 24 fixed above the round plate 39 (the distribution of the columns 24 is shown in FIG. Figure 7 The middle rod section of the round rod 25 is semicircular (as shown in FIG. Figure 8 As shown), the middle rod portion of the round rod 25 of the fork is in the notch of the fork seat 33; Figure 5 As shown, the upper part of the fork seat 33 is provided with an annular groove 331, and a torsion spring is arranged in the annular groove 331, and the two ends of the torsion spring are respectively inserted into the bottom of the circular plate 39 and the bottom of the annular groove 331; Figure 7 As shown, a disc 22 is fixedly provided on the stem portion of the valve stem 23, and the disc 22 is located between two columns 24. Figure 5 As shown, a pressure-loss cylinder 34 is provided at the end of the valve stem 23 away from the piston 31. The pressure-loss cylinder 34 can slide axially in the spring cavity 21. A pressure-loss spring 35 is provided inside the pressure-loss cylinder 34. A pressure-loss spring cover 38 is threadedly connected to the end of the pressure-loss cylinder 34 away from the valve stem 23. An overpressure spring 36 is sleeved on the outer periphery of the pressure-loss cylinder 34. An overpressure spring cover 37 is threadedly connected to the spring cavity 21 at the end of the overpressure spring 36 away from the valve stem 23.

[0051] like Fig.10 As shown, the swing hook 26 is horizontally arranged in the reset mechanism, the middle part of the swing hook 26 is rotatably connected to the bottom plate 10 through the positioning pin 28, and the rotation connection point of the swing hook 26 is provided with a torsion spring, the end of the swing hook 26 close to the round rod 25 of the fork is the knife tip, the knife tip of the swing hook 26 is the sharp corner 29, the angle of the sharp corner 29 is 69°40′ to 70°20′, and the preferred angle in this embodiment is 70° (if the angle is less than this range, the tip of the sharp corner 29 is thinner, the strength is reduced, and the service life is reduced, if the angle is greater than this range, the knife tip is easy to interfere with the round rod 25 when swinging, causing the sharp corner 29 to be unable to quickly detach from the arc surface of the round rod 25). The end of the swing hook 26 close to the pin 12 is the hook groove end, and the hook groove end is provided with a bayonet 27; the semicircular cross-section of the middle rod portion of the round rod 25 of the fork can clamp the knife tip of the swing hook 26, and the pin 12 is located in the bayonet 27 of the hook groove end and can clamp the hook groove end.

[0052] The use of this cut-off valve is as follows:

[0053] Will Figure 5 The inlet of the piston cavity 32 is connected to the air inlet end 1 of the valve body 3. When the pressure of the air inlet end 1 increases (overpressure state), the piston 31 pushes the valve stem 23 to Figure 5 Slide the right side of the disk 22 to the right Figure 7 The column 24 on the right side drives the entire fork Figure 7 Zhongan rotates clockwise, Fig.10 The round rod 25 in the middle rotates in the clockwise direction. During the rotation, the arc surface of the round rod 25 will gradually separate from the sharp corner 29 of the swing hook 26. At this time, under the action of the torsion spring on the positioning pin 28, the swing hook 26 will swing in the clockwise direction. A stop pin 40 is provided on the right side of the swing hook 26 on the bottom plate 10 to prevent the swing hook 26 from swinging too far. After the swing is in place, the pin 12 is separated from the bayonet 27, and the pin 12 is no longer tightened by the swing hook 26. Therefore, Figure 2 Neutralization Fig. 9 The elastic force of the blocking spring 6 in the valve body will push the baffle 7 on the valve cylinder 5, and the baffle 7 will push the screw 8 and drive the connecting plate 142 to Fig. 9 Rotate counterclockwise so that Figure 2 The end of the valve cylinder 5 near the valve seat 17 moves axially and fastens on the surface of the valve disc 16 to complete the pipeline blocking. Similarly, when the pressure at the inlet end 1 decreases (pressure loss state), Figure 5 The elastic force of the pressure-loss spring 35 pushes the valve stem 23 to move to the left, and the disc 22 moves Figure 7 The column 24 on the left side also drives the entire fork Figure 7 Zhongan rotates clockwise, and its triggering principle is the same as that of the overpressure state, which will not be repeated here.

[0054] When the air pressure returns to normal, Figure 1 The balance valve 19 connected between the air inlet end 1 and the air outlet end 2 on the valve body 3 is opened to balance the air pressure at both ends of the valve body 3. Then, a wrench is inserted into the Figure 2 The square hole on the rotating sleeve 30 in the Fig.10 The rotating sleeve 30 is pulled clockwise so that the pin 12 on the rotating sleeve 30 is re-engaged in the bayonet 27, and the sharp corner 29 of the swing hook 26 is returned to the left side of the round rod 25 to complete the reset.

[0055] The above are only embodiments of the present invention. The invention is not limited to the fields involved in this implementation case. The common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. An axial flow gas shut-off valve, comprising a valve body, a valve cylinder slidably connected in the valve body, and a shut-off mechanism fixed on the valve body; the shut-off mechanism is used to control the axial movement of the valve cylinder in the valve body, characterized in that: The cutting mechanism includes a bottom plate fixed on the valve body, a reset mechanism fixed on the bottom plate, a swing hook rotatably connected in the reset mechanism, and a trigger mechanism located on one side of the reset mechanism; A shift fork is connected to the trigger mechanism for rotation in a vertical direction, and the cross section of the shift fork is semicircular. A rotary sleeve is connected to the reset mechanism for rotation in a vertical direction, and a pin is vertically fixed on the rotary sleeve. The swing hook is horizontally arranged in the reset mechanism, and a torsion spring is arranged at the rotation connection point of the swing hook, one end of the swing hook is a knife tip, and the other end of the swing hook is a hook slot end, and a bayonet is arranged at the hook slot end; The arc surface of the shift fork is used to clamp the tip of the swing hook, and the pin is located in the clamping mouth of the hook groove end and can clamp the hook groove end; when the shift fork rotates, the pin can be controlled to disengage from the clamping mouth of the swing hook.

2. An axial flow gas shut-off valve according to claim 1, characterized in that: The trigger mechanism includes a spring cavity fixed on the bottom plate, a piston cavity fixed on the spring cavity, a piston slidably connected in the piston cavity, a valve stem slidably connected in the spring cavity and a fork seat fixed in the spring cavity, wherein the fork is rotatably connected to the fork seat; a disc is fixedly provided on the stem portion of the valve stem, a pressure-loss cylinder is provided at one end of the valve stem away from the piston, the pressure-loss cylinder can slide axially in the spring cavity, a pressure-loss spring is provided inside the pressure-loss cylinder, and an overpressure spring is provided outside the pressure-loss cylinder.

3. An axial flow gas shut-off valve according to claim 2, characterized in that: The tip of the swing hook is a sharp angle, and the angle of the sharp angle is 69°40′ to 70°20′.

4. An axial flow gas shut-off valve according to claim 3, characterized in that: The shift fork comprises an integrally formed round rod, a round plate fixed above the round rod and a column fixed above the round plate. The column is arranged above the round plate and close to the outer circle. The middle rod portion of the round rod has a semicircular cross section.

5. An axial flow gas shut-off valve according to claim 4, characterized in that: A notch is provided on the fork seat, and the middle rod portion of the round rod of the fork is located in the notch.

6. An axial flow gas shut-off valve according to claim 5, characterized in that: The reset mechanism includes a shell fixed on the bottom plate, a rotary sleeve rotatably connected to the shell, a turntable located below the rotary sleeve and a screw fixed to the bottom of the turntable. A through square hole is provided in the middle of the rotary sleeve. The turntable includes an integrally formed square rod and a connecting disk fixed below the square rod. The screw is vertically fixed to the bottom of the connecting disk near the outer circle. The upper side of the square rod extends into the square hole of the rotary sleeve. The lower end of the square rod and the connecting disk are located in the valve body.

7. An axial flow gas shut-off valve according to claim 6, characterized in that: The reset mechanism also includes a baffle fixed on the outer periphery of the valve cylinder and a blocking spring sleeved on the valve cylinder. The blocking spring is located in the space formed by the baffle and the inner cavity of the valve body. The screw at the bottom of the connecting plate is located on the side of the baffle away from the blocking spring.

8. An axial flow gas shut-off valve according to claim 7, characterized in that: The valve body is also provided with a valve seat, which has a plurality of arc-shaped holes evenly distributed along the circumference. A pressure cover is fixed at the center of the valve seat, and a valve disc is fixed between the valve seat and the pressure cover. The end face of the valve cylinder on the screw side can be pressed against the surface of the valve disc to seal the valve body.

9. An axial flow gas shut-off valve according to claim 8, characterized in that: An O-ring is also provided on the sliding connection surface between the valve body and the valve cylinder.

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