Intelligent natural gas wellhead emergency shut-off valve and control method thereof

Abstract

The intelligent natural gas wellhead emergency shut-off valve of the present invention relates to the field of gas field gas production technology, specifically to an emergency shut-off valve that can be used for gas field gas production wellhead, and particularly to an intelligent natural gas wellhead emergency shut-off valve, including a valve body connecting an air inlet pipe and an air outlet pipe, wherein a valve seat is arranged in the valve body, and the valve seat divides the internal area of ​​the valve body into two sealing areas connecting the air inlet pipe and the air outlet pipe; the present invention has a simple structure, and a valve stem is fixedly connected to a valve core by a valve stem, and the movement of the valve stem realizes the sealing or separation of the valve core from a connecting hole, so that the air inlet pipe and the air outlet pipe are connected or blocked with each other, and a limiting mechanism is driven to separate from the restriction of the limiting platform by a disengaging driving device, so that the valve stem is moved toward the connecting hole, so that the valve core seals the connecting hole, and a resetting device is used to realize the movement of the valve stem away from the connecting hole, so that the valve core is separated from the connecting hole, thereby facilitating the cutting off or connection of the natural gas pipeline in an emergency.

Description

Technical Field

[0001] The invention relates to the field of gas field gas production technology, in particular to an emergency cut-off valve that can be used for a gas field gas production wellhead, and in particular to an intelligent natural gas wellhead emergency cut-off valve. Background Art

[0002] The Yan'an gas field has complex terrain conditions, low single-well production, and fast pressure drop rate; the blocks that were put into production in the early stage have entered the middle and late stages of development, and the number of intermittent wells has increased year by year, making gas well production management more difficult. Manual intermittent well switching operations are frequent, and maintenance costs are rising year by year. In addition, normal production may be affected due to untimely well switching. Especially for special working conditions such as rainy and snowy weather and sulfur-containing gas, the safety risk of on-site operations is higher. Therefore, the development of an intelligent natural gas wellhead emergency shut-off valve is particularly important for improving production efficiency, reducing employee labor intensity and on-site operation safety risks, and reducing production costs. Summary of the invention

[0003] In order to solve the above problems, the present invention provides an intelligent natural gas wellhead emergency shut-off valve which can grasp the gas well opening and closing status in real time, realize the gas well remote opening and closing, and greatly reduce the production cost and labor intensity of personnel.

[0004] The present invention discloses an intelligent natural gas wellhead emergency shut-off valve, comprising a valve body connected to an air inlet pipe and an air outlet pipe, wherein a valve seat is arranged in the valve body, and the valve seat divides the internal area of ​​the valve body into two sealing areas connected to the air inlet pipe and the air outlet pipe, and the valve body is provided with a connecting hole connected to the two sealing areas, and a valve core is matched and connected to the connecting hole, and a valve stem is fixedly connected to the valve core, and one end of the valve stem away from the valve core passes through the sealing area, and the valve stem moves along its axial direction to drive the valve core to block or disengage from the connecting hole;

[0005] The valve body is provided with a guide groove, one end of the valve stem away from the valve core is slidably arranged in the guide groove, a limit platform is fixedly arranged on the valve stem, a third energy storage spring is sleeved on the valve stem between the guide groove and the limit platform, a limit mechanism for limiting the extension of the third energy storage spring is connected to the side of the limit platform away from the third energy storage spring, and a release drive device is connected to the limit mechanism;

[0006] When the release drive device is activated, the third energy storage spring is extended, and the valve stem moves toward the connecting hole, driving the valve core to block the through hole;

[0007] The valve stem is also provided with a resetting device.

[0008] Preferably, the release drive device includes a piston and a three-way valve;

[0009] The piston comprises a sealing baffle slidably arranged in the piston, the sealing baffle divides the internal chamber of the piston into a rod chamber and an air chamber, a piston rod is arranged in the rod chamber, one end of the piston rod is fixedly connected to the sealing baffle, and the other end extends out of the rod chamber and is fixedly connected to a release rack, and the central axis of the piston rod and the central axis of the release rack are located on the same straight line;

[0010] A release gear is rotatably provided on the valve body, the release gear is meshed with the release rack, a connecting rope tightening column is fixedly connected to one surface of the release gear, the connecting rope tightening column is connected to the limit mechanism through the connecting rope, and when the release gear rotates, the connecting rope tightening column drives the limit mechanism to release the limit;

[0011] The three-way valve is connected to the air intake pipe through the natural gas pipeline before the inlet, and is connected to the air cavity of the piston through the piston air cavity inlet pipeline. The three-way valve is also connected to an exhaust pipeline, and is connected to a pressure switch that controls the connection between the natural gas pipeline before the inlet and the piston air cavity inlet pipeline.

[0012] Preferably, the limiting mechanism comprises two limiting pins that act synchronously, the two limiting pins are slidably arranged on the valve body, and the central axes of the two limiting pins are perpendicular to the central axis of the valve stem;

[0013] The two limit pins are symmetrically arranged on both sides of the valve stem, and the ends of the two limit pins that are away from each other are fixedly connected to the connecting rope tightening column through a connecting rope;

[0014] When the release gear drives the connecting rope tightening column to rotate, the connecting rope connected to the limit pin is wound around the connecting rope tightening column, the two limit pins move away from each other, and the limit platform passes through the area between the two limit pins and moves toward the valve core along the axial direction of the valve stem;

[0015] The limit pins are all provided with limit pin resetting devices.

[0016] Preferably, the limit pin reset device is a reset spring, one end of the reset spring is fixedly connected to the end of the limit pin that is away from each other, and the other end of the reset spring is fixedly connected to the valve body through a connecting piece;

[0017] The return springs are all sleeved outside the connecting rope;

[0018] When the limit release gear drives the connecting rope tightening column to rotate, the connecting rope is pulled, the return spring is compressed, and the two limit pins move away from each other.

[0019] Preferably, the connecting ropes on the same limiting pin are all wound around the two reversing pins and then fixedly connected to the connecting rope tightening column.

[0020] Preferably, the reset device comprises a reset rack fixedly arranged on the valve stem, and a reset gear is meshingly connected to the reset rack. When the reset gear rotates, the valve stem is driven to move toward or away from the connecting hole.

[0021] Preferably, a manual reset device is connected to the reset gear, and the manual reset device includes an operating handle, which is rotatably connected to the valve body, one end of the operating handle is fixedly connected to the reset gear, and the central axis of the operating handle and the rotation axis of the reset gear are located on the same straight line.

[0022] Preferably, the reset gear is connected to an electric reset device, the electric reset device comprises a motor, the motor shaft is fixedly connected to the reset gear, the central axis of the motor shaft and the rotation axis of the reset gear are located on the same straight line, and the motor is fixedly arranged on the valve body.

[0023] Or preferably, the valve body is also connected to a safety protection device to prevent the valve core from accidentally detaching from the through hole. When the valve core is blocked on the connecting hole, the safety protection device limits the movement of the valve stem.

[0024] Preferably, the safety protection device comprises a limit chuck, and the limit chuck is arranged on the valve stem between the sealing area and the reset device;

[0025] It also includes a limit rod, the limit rod includes a limit safety rod and a limit operating rod that are fixedly connected, the connection between the limit safety rod and the limit operating rod is rotatably connected to the valve body, and the angle between the limit safety rod and the limit operating rod is an obtuse angle. When the limit operating rod rotates, the limit safety rod abuts against the limit chuck and limits the valve stem from moving away from the connecting hole, or from the limit chuck.

[0026] A safety reset device is arranged on one side of the limit operating rod, and a limit push rod is arranged on the other side corresponding to the position of the safety reset device. The limit push rod is slidably connected to the valve body. When the limit push rod slides on the valve body toward the limit push rod, the limit operating rod is pushed to rotate toward the safety reset device.

[0027] The safety reset device comprises a reset base fixedly arranged on the valve body, a hollow sleeve is arranged on the reset base, the sleeve is arranged toward the limit operating rod, a safety reset column is slidably sleeved in the sleeve, one end of the safety reset column extends out of the sleeve and is arranged toward the limit operating rod, and the other end is connected to the bottom surface of the sleeve through a safety reset spring, when the limit operating rod squeezes the safety reset column, the safety reset spring is compressed;

[0028] The limit push rod is sleeved with a first retaining ring and a second retaining ring, the first retaining ring is fixedly connected to the limit push rod, the second retaining ring is fixedly connected to the valve seat, and the second retaining ring is movably connected to the limit push rod, and a second energy storage spring is sleeved on the limit push rod between the first retaining ring and the second retaining ring;

[0029] A stopper is fixedly connected to the limit push rod, a vertical displacement rod and a horizontal displacement rod are vertically arranged below the limit push rod, a vertical rack is fixedly arranged on the vertical displacement rod, a horizontal rack is fixedly arranged on the horizontal displacement rod, and both the vertical displacement rod and the horizontal displacement rod are slidably connected to the valve body, the vertical rack and the horizontal rack are meshed with the same transmission gear, and the transmission gear is rotatably arranged on the valve body;

[0030] The stopper is arranged toward the vertical displacement rod. When the limit push rod slides on the valve body and the stopper contacts the vertical displacement rod, the vertical displacement rod restricts the limit push rod from sliding.

[0031] The lateral moving rod is provided with a roller on one end facing the limit chuck, and a third retaining ring and a fourth retaining ring are sleeved on the other end, the third retaining ring is fixedly connected to the lateral moving rod, the fourth retaining ring is fixedly connected to the valve body, and the fourth retaining ring is movably connected to the lateral moving rod, the third retaining ring is arranged on the lateral moving rod between the fourth retaining ring and the lateral rack, and a lateral return spring is arranged on the step of the lateral displacement rod between the third retaining ring and the fourth retaining ring,

[0032] A convex rod is arranged on the side of the limit chuck facing the lateral displacement rod. When the limit chuck moves toward or away from the connecting hole along with the valve stem, the convex rod squeezes the roller when passing through the roller and pushes the lateral displacement rod to slide in the direction away from the limit chuck.

[0033] The present invention has a simple structure. The valve stem is fixedly connected to the valve core, and the movement of the valve stem is used to seal or disengage the valve core from the connecting hole, so that the air inlet pipe and the air outlet pipe are connected or blocked with each other. The limit release driving device drives the limit mechanism to disengage from the restriction of the limit platform, thereby realizing the movement of the valve stem toward the connecting hole, so that the valve core blocks the connecting hole. The reset device is used to realize the movement of the valve stem away from the connecting hole, so that the valve core is separated from the connecting hole, thereby facilitating the cutting off or connecting of the natural gas pipeline in an emergency.

[0034] The present invention utilizes the safety protection device to achieve position limiting after the valve core blocks the communicating hole, thereby ensuring the safety of the use process.

[0035] The present invention improves the efficiency of gas well management, increases the execution of the intermittent switch system from days to hours, improves the accuracy of the intermittent system, and facilitates timely adjustment of the intermittent system according to the production situation of the gas well.

[0036] The present invention reduces the risk of safety management and control, transforms personnel operations from on-site operations to indoor remote control, greatly reduces the risk of personnel injury due to factors such as riding in a vehicle and on-site operations, and at the same time greatly shortens the emergency well shut-in response time caused by overpressure at the gas gathering station and pipeline leakage.

[0037] The present invention reduces the cost of gas well management and maintenance. An intelligent natural gas wellhead emergency shut-off valve and a control method thereof basically solve the problem of a large number of intermittent well switching operations, greatly reducing the manpower cost required for on-site well switching. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the structure of the present invention.

[0039] Figure 2 It is a schematic diagram of the safety protection device structure.

[0040] Figure 3 Open the control flow chart for the present invention.

[0041] Figure numerals: 1-valve body, 2-valve seat, 3-valve core, 4-limit chuck, 5-valve stem, 6-motor, 7-motor shaft, 8-reset gear, 9-reset rack, 10-piston, 11-sealing baffle, 12-third energy storage spring, 13-piston cylinder inlet pipeline, 14-release rack, 15-three-way valve, 16-release gear, 17-limit pin, 18-pressure switch, 20-natural gas pipeline before inlet, 21-operating handle, 22-fourth retaining ring, 23-lateral return spring, 24-lateral displacement rod, 25-roller, 26-convex rod, 27-limiter, 28-safety return spring, 29-sleeve, 31-second energy storage spring, 32-manual reset button, 33-electric reset button, 34-block, 35-vertical displacement rod, 36-transmission gear. DETAILED DESCRIPTION

[0042] The present invention discloses an intelligent natural gas wellhead emergency shut-off valve, comprising a valve body 1 connected to an air inlet pipe and an air outlet pipe, wherein a valve seat 2 is arranged inside the valve body 1, and the valve seat 2 divides the internal area of ​​the valve body 1 into two sealing areas connected to the air inlet pipe and the air outlet pipe, and the valve body 1 is provided with a connecting hole connecting the two sealing areas, and a valve core 3 is matched and connected to the connecting hole, and a valve stem 5 is fixedly connected to the valve core 3, and one end of the valve stem 5 away from the valve core 3 passes through the sealing area, and the valve stem 5 moves along its axial direction, driving the valve core 3 to block or disengage from the connecting hole;

[0043] The valve body 1 is provided with a guide groove, and one end of the valve stem 5 away from the valve core 3 is slidably arranged in the guide groove. A limit platform is fixedly arranged on the valve stem 5, and a third energy storage spring 12 is sleeved on the valve stem 5 between the guide groove and the limit platform. A limit mechanism for limiting the extension of the third energy storage spring 12 is connected to the side of the limit platform away from the third energy storage spring 12, and a release drive device is connected to the limit mechanism.

[0044] When the release drive device is activated, the third energy storage spring 12 is stretched, and the valve stem 5 moves toward the connecting hole, driving the valve core 3 to block the through hole;

[0045] The valve stem 5 is also provided with a reset device.

[0046] The release driving device includes a piston 10 and a three-way valve 15;

[0047] The piston 10 includes a sealing baffle 11 slidably disposed in the piston 10, and the sealing baffle 11 divides the internal chamber of the piston 10 into a rod chamber and an air chamber. A piston 10 rod is disposed in the rod chamber, and one end of the piston 10 rod is fixedly connected to the sealing baffle, and the other end extends out of the rod chamber and is fixedly connected to a release rack 14, and the central axis of the piston 10 rod and the central axis of the release rack 14 are located on the same straight line;

[0048] The valve body 1 is rotatably provided with a release gear 16, which is meshed with the release rack 14, and a connecting rope tightening column is fixedly connected to one surface of the release gear 16, and the connecting rope tightening column is connected to the limit mechanism through the connecting rope, and the release gear 16 rotates, and the connecting rope tightening column drives the limit mechanism to release the limit;

[0049] The three-way valve 15 is connected to the air intake pipe through the pre-inlet natural gas pipeline 20, and the three-way valve 15 is connected to the air cavity of the piston 10 through the piston air cavity inlet pipeline 13. The three-way valve 15 is also connected to an exhaust pipeline, and the three-way valve 15 is connected to a pressure switch 18 that controls the connection between the pre-inlet natural gas pipeline 20 and the piston air cavity inlet pipeline 13.

[0050] The limiting mechanism includes two limiting pins 17 that act synchronously. The two limiting pins 17 are slidably arranged on the valve body 1, and the central axes of the two limiting pins 17 are perpendicular to the central axis of the valve stem 5.

[0051] Two limit pins 17 are symmetrically arranged on both sides of the valve stem 5, and the ends of the two limit pins 17 that are away from each other are fixedly connected to the connecting rope tightening column through a connecting rope;

[0052] When the release gear 16 drives the connecting rope tightening column to rotate, the connecting rope connected to the limit pin 17 is wound around the connecting rope tightening column, the two limit pins 17 move away from each other, and the limit platform passes through the area between the two limit pins 17 and moves toward the valve core 3 along the axial direction of the valve stem 5;

[0053] The limit pins 17 are each provided with a limit pin 17 resetting device.

[0054] The reset device of the limit pin 17 is a reset spring, one end of which is fixedly connected to the end of the limit pin 17 that is away from each other, and the other end of which is fixedly connected to the valve body 1 through a connecting piece;

[0055] The return springs are all sleeved outside the connecting rope;

[0056] When the release gear 16 drives the connecting rope tightening column to rotate, the connecting rope is pulled, the return spring is compressed, and the two limit pins 17 move away from each other.

[0057] The connecting ropes on the same limiting pin 17 are all wound around the two reversing pins and are fixedly connected to the connecting rope tightening column.

[0058] The reset device comprises a reset rack 9 fixedly arranged on the valve stem 5, and a reset gear 8 is meshingly connected to the reset rack 9. When the reset gear 8 rotates, the valve stem 5 is driven to move toward or away from the connecting hole.

[0059] A manual reset device is connected to the reset gear 8, and the manual reset device includes an operating handle 21, which is rotatably connected to the valve body 1, one end of the operating handle 21 is fixedly connected to the reset gear 8, and the central axis of the operating handle 21 is on the same straight line as the rotation axis of the reset gear 8.

[0060] The reset gear 8 is connected to an electric reset device, which includes a motor 6. The motor shaft 7 is fixedly connected to the reset gear 8. The central axis of the motor shaft 7 and the rotation axis of the reset gear 8 are located on the same straight line. The motor 6 is fixedly arranged on the valve body 1.

[0061] The valve body 1 is also connected with a safety protection device to prevent the valve core 3 from accidentally escaping from the through hole. When the valve core 3 is blocked on the connecting hole, the safety protection device restricts the movement of the valve stem 5.

[0062] The safety protection device comprises a limit chuck 4, which is arranged on the valve stem 5 between the sealing area and the reset device;

[0063] It also includes a limit rod, which includes a limit safety rod and a limit operating rod that are fixedly connected. The connection between the limit safety rod and the limit operating rod is rotatably connected to the valve body 1, and the angle between the limit safety rod and the limit operating rod is an obtuse angle. When the limit operating rod rotates, the limit safety rod abuts against the limit chuck 4 and limits the valve stem 5 from moving away from the connecting hole, or from the limit chuck 4.

[0064] A safety reset device is provided on one side of the limit operating rod, and a limit push rod is provided on the other side corresponding to the position of the safety reset device. The limit push rod is slidably connected to the valve body 1. When the limit push rod slides on the valve body 1 toward the limit push rod, the limit operating rod is pushed to rotate toward the safety reset device.

[0065] The safety reset device comprises a reset base fixedly arranged on the valve body 1, a hollow sleeve 29 is arranged on the reset base, the sleeve 29 is arranged toward the limit operating rod, a safety reset column is slidably sleeved in the sleeve 29, one end of the safety reset column extends out of the sleeve 29 and is arranged toward the limit operating rod, and the other end is connected to the bottom surface of the sleeve 29 through a safety reset spring 28. When the limit operating rod squeezes the safety reset column, the safety reset spring 28 is compressed;

[0066] The limit push rod is sleeved with a first retaining ring and a second retaining ring, the first retaining ring is fixedly connected to the limit push rod, the second retaining ring is fixedly connected to the valve seat 2, and the second retaining ring is movably connected to the limit push rod, and the limit push rod between the first retaining ring and the second retaining ring is sleeved with a second energy storage spring 31;

[0067] A stopper 34 is fixedly connected to the limit push rod, and a vertical displacement rod 35 and a lateral displacement rod 24 are vertically arranged below the limit push rod. A vertical rack is fixedly arranged on the vertical displacement rod 35, and a lateral rack is fixedly arranged on the lateral displacement rod 24. The vertical displacement rod 35 and the lateral displacement rod 24 are both slidably connected to the valve body 1, and the vertical rack and the lateral rack are meshed with the same transmission gear 36, and the transmission gear 36 is rotatably arranged on the valve body 1;

[0068] The stopper 34 is arranged toward the vertical displacement rod 35. When the limit push rod slides on the valve body 1 and the stopper 34 contacts the vertical displacement rod 35, the vertical displacement rod 35 restricts the limit push rod from sliding.

[0069] A roller 25 is arranged on one end of the lateral movement rod facing the limit chuck 4, and a third retaining ring and a fourth retaining ring 22 are sleeved on the other end, wherein the third retaining ring is fixedly connected to the lateral movement rod, the fourth retaining ring 22 is fixedly connected to the valve body 1, and the fourth retaining ring 22 is movably connected to the lateral movement rod, and the third retaining ring is arranged on the lateral movement rod between the fourth retaining ring 22 and the lateral rack, and a lateral return spring 23 is arranged on the step of the lateral displacement rod 24 between the third retaining ring and the fourth retaining ring 22,

[0070] A protruding rod 26 is provided on the side of the limit chuck 4 facing the lateral displacement rod. When the limit chuck 4 moves toward or away from the connecting hole along with the valve stem 5, the protruding rod 26 squeezes the roller 25 when passing through the roller 25, and pushes the lateral displacement rod 24 to slide in the direction away from the limit chuck 4.

[0071] The pressure switch 18 is a mechanical pressure switch 18: model TL0202, the manufacturer is Changzhou Tianli Intelligent Control Co., Ltd. When the inlet pressure of the present invention exceeds or is lower than the set value, the pressure switch 18 controls the left and right sides of the three-way valve 15 to be in a conducting state, that is, the natural gas pipeline 20 before the inlet is connected to the air cavity of the piston 10.

[0072] The present invention is installed at the natural gas wellhead. When the pressure at the natural gas wellhead is normal, the present invention is in an open state, that is, the air inlet pipe and the air outlet pipe are connected, and the natural gas well produces normally.

[0073] When the pressure switch 18 detects that the wellhead pressure is overpressure or underpressure, the present invention is triggered to quickly close the valve body 1, cut off the natural gas well, and improve the production safety of the natural gas well.

[0074] After the gas well fault is eliminated and the wellhead pressure returns to normal, the reset device is manually or electrically started to open the valve body 1, and the natural gas well is produced normally.

[0075] Specifically, during normal production, the valve body 1 is in an open state, the pressure value of the pressure switch 18 is set according to the safety range of the wellhead pressure, the pressure before the emergency shut-off valve is within the set value, and the limit pin 17 is located at the bottom of the limit chuck 4 to block the energy storage spring from pressing down the valve stem 5; the limit operating lever of the limit rod is in a non-pressed state, the limit safety lever is located on one side of the limit chuck 4, and the second energy storage spring 31 of the limiter 27 push rod is in a non-compressed state.

[0076] When the pressure before the emergency shut-off valve exceeds or falls below the set value, Figure 1 As shown, the pressure switch 18 controls the left and right sides of the three-way valve 15 to be in a conducting state, and the natural gas pipeline 20 in front of the inlet is connected to the air cavity of the piston 10. The gas pushes the piston 10 to move leftward, driving the limit release gear 16 to rotate counterclockwise, pulling the two limit pins 17 away from each other, and the third energy storage spring 12 pushes the valve stem 5 to move downward, the valve core 3 blocks the connecting hole, and the valve is closed.

[0077] At the same time, the protruding rod 26 on the limit chuck 4 moves downward along with the valve stem 5. Figure 2 As shown, the lateral displacement rod 24 is pushed to move left, driving the transmission gear 36 to rotate clockwise, and the vertical displacement rod 35 is driven to move downward through the vertical rack, and the position restriction of the limit push rod is lost. The second energy storage spring 31 bounces the limit push rod to the left, and the limit operating rod is in a non-pressed state; when the valve is completely closed, the limit safety rod is above the limit chuck 4 to prevent the valve from opening due to high pressure.

[0078] After the natural gas wellhead fault is eliminated and the pressure returns to normal, the pressure switch 18 is turned on to control the three-way valve 15 to connect the venting pipeline and the air cavity of the piston 10, and the gas in the piston 10 is vented through the three-way valve 15 to prepare for the next emergency shutdown. The valve body 1 needs to be opened; first, it needs to be electrically reset, and then the control motor 6 is started to drive the valve stem 5 to move upward to open the valve. The valve can also be opened by the hand wheel.

[0079] Specifically, first press the manual reset button 32 or the electric reset button 33. The manual or electric reset button 33 pushes the limit push rod to move to the left, pushes the limit operating rod to rotate clockwise, so that the limit safety rod moves to one side of the limit chuck 4, and the restriction on the limit chuck 4 is released; at the same time, the limit push rod is stuck by the vertical displacement rod 35 after moving to the right and cannot move to the right; at this time, turn on the motor 6 or rotate the handwheel to drive the valve stem 5 to move upward and open the valve body 1. During the upward movement of the valve stem 5, the convex rod 26 pushes the lateral displacement rod 24 to move left, the transmission gear 36 rotates clockwise, and the vertical displacement rod 35 moves downward, losing the position restriction on the limiter 27 push rod, and the second energy storage spring 31 bounces the limiter 27 push rod to the left. The limiter 27 is in a non-pressed state, and the lower end of the limit rod is on the left side of the limit chuck 4, restoring the normal production state.

Claims

1. An intelligent natural gas wellhead emergency shut-off valve, comprising a valve body (1) connected to an air inlet pipe and an air outlet pipe, wherein a valve seat (2) is arranged in the valve body (1), and the valve seat (2) divides the internal area of ​​the valve body (1) into two sealing areas connected to the air inlet pipe and the air outlet pipe, and the valve body (1) is provided with a connecting hole connecting the two sealing areas, and a valve core (3) is matched and connected to the connecting hole, and a valve stem (5) is fixedly connected to the valve core (3), and an end of the valve stem (5) away from the valve core (3) passes through the sealing area, and the valve stem (5) moves along its axial direction to drive the valve core (3) to block or disengage from the connecting hole; It is characterized in that The valve body (1) is provided with a guide groove, one end of the valve stem (5) away from the valve core (3) is slidably arranged in the guide groove, a limit platform is fixedly arranged on the valve stem (5), a third energy storage spring (12) is sleeved on the valve stem (5) between the guide groove and the limit platform, a limit mechanism for limiting the extension of the third energy storage spring (12) is connected to a surface of the limit platform away from the third energy storage spring (12), and a release drive device is connected to the limit mechanism; When the release drive device is activated, the third energy storage spring (12) is stretched, and the valve stem (5) moves toward the connecting hole, driving the valve core (3) to block the through hole; The valve stem (5) is also provided with a reset device; The release drive device comprises a piston (10) and a three-way valve (15); The piston (10) comprises a sealing baffle (11) slidably arranged in the piston (10), wherein the sealing baffle (11) divides the internal chamber of the piston (10) into a rod chamber and an air chamber, wherein a piston rod is arranged in the rod chamber, wherein one end of the piston rod is fixedly connected to the sealing baffle, and the other end of the piston rod extends out of the rod chamber and is fixedly connected to a release rack (14), wherein the central axis of the piston rod and the central axis of the release rack (14) are located on the same straight line; A release gear (16) is rotatably provided on the valve body (1), the release gear (16) and the release rack (14) are meshed with each other, a connecting rope tightening column is fixedly connected to one surface of the release gear (16), the connecting rope tightening column is connected to the limit mechanism via a connecting rope, and when the release gear (16) rotates, the connecting rope tightening column drives the limit mechanism to release the limit; The three-way valve (15) is connected to the air inlet pipe via the pre-inlet natural gas pipeline, the three-way valve (15) is connected to the air cavity of the piston (10) via the piston air cavity inlet pipeline (13), the three-way valve (15) is also connected to an exhaust pipeline, and the three-way valve (15) is connected to a pressure switch (18) for controlling the connection between the pre-inlet natural gas pipeline (20) and the piston air cavity inlet pipeline (13); The limiting mechanism comprises two limiting pins (17) that act synchronously, the two limiting pins (17) being slidably arranged on the valve body (1), and the central axes of the two limiting pins (17) are perpendicular to the central axis of the valve stem (5); The two limit pins (17) are symmetrically arranged on both sides of the valve stem (5), and the ends of the two limit pins (17) that are away from each other are fixedly connected to the connecting rope tightening column through a connecting rope; When the release gear (16) drives the connecting rope tightening column to rotate, the connecting rope connected to the limit pin (17) is wound around the connecting rope tightening column, the two limit pins (17) move away from each other, and the limit platform passes through the area between the two limit pins (17) and moves toward the valve core (3) along the axial direction of the valve stem (5); The limit pin (17) is provided with a limit pin (17) resetting device; The reset device comprises a reset rack (9) fixedly arranged on the valve stem (5), the reset rack (9) being meshingly connected with a reset gear (8), and when the reset gear (8) rotates, the valve stem (5) is driven to move towards or away from the connecting hole; The reset gear (8) is connected to a manual reset device, the manual reset device comprising an operating handle (21), the operating handle (21) being rotationally connected to the valve body (1), one end of the operating handle (21) being fixedly connected to the reset gear (8), and a central axis of the operating handle (21) and a rotation axis of the reset gear (8) being located on the same straight line.

2. An intelligent natural gas wellhead emergency shut-off valve as claimed in claim 1, characterized in that: The limit pin (17) reset device is a reset spring, one end of the reset spring is fixedly connected to the end of the limit pin (17) that is away from each other, and the other end of the reset spring is fixedly connected to the valve body (1) via a connecting piece; The return springs are all sleeved outside the connecting rope; When the release gear (16) drives the connecting rope tightening column to rotate, the connecting rope is pulled, the return spring is compressed, and the two limit pins (17) move away from each other; The connecting ropes on the same limit pin (17) are all wound around the two reversing pins and are fixedly connected to the connecting rope tightening column.

3. An intelligent natural gas wellhead emergency shut-off valve as claimed in claim 2, characterized in that: The reset gear (8) is connected to an electric reset device, the electric reset device comprising a motor (6), the motor (6) being connected to a motor shaft (7), the motor shaft (7) being fixedly connected to the reset gear (8), the central axis of the motor shaft (7) and the rotation axis of the reset gear (8) being located on the same straight line, and the motor (6) being fixedly arranged on the valve body (1).

4. An intelligent natural gas wellhead emergency shut-off valve as claimed in claim 3, characterized in that: The valve body (1) is also connected to a safety protection device for preventing the valve core (3) from accidentally detaching from the through hole. When the valve core (3) is blocked on the communicating hole, the safety protection device restricts the movement of the valve stem (5).

5. An intelligent natural gas wellhead emergency shut-off valve as claimed in claim 4, characterized in that: The safety protection device comprises a limit chuck (4), wherein the limit chuck (4) is arranged on the valve stem (5) between the sealing area and the reset device; It also includes a limit rod, the limit rod including a limit safety rod and a limit operating rod that are fixedly connected, the limit safety rod and the limit operating rod are connected at a connection point that is rotatably connected to the valve body (1), and the angle between the limit safety rod and the limit operating rod is an obtuse angle, and when the limit operating rod rotates, the limit safety rod abuts against the limit chuck (4) and limits the valve stem (5) from moving away from the connecting hole, or from being separated from the limit chuck (4); A safety reset device is arranged on one side of the limit operating rod, and a limit push rod is arranged on the other side corresponding to the position of the safety reset device, the limit push rod is slidably connected to the valve body (1), and when the limit push rod slides on the valve body (1) toward the limit push rod, the limit operating rod is pushed to rotate toward the safety reset device; The safety reset device comprises a reset base fixedly arranged on the valve body (1), a hollow sleeve (29) being arranged on the reset base, the sleeve (29) being arranged towards the limit operating rod, a safety reset column being slidably sleeved in the sleeve (29), one end of the safety reset column extending out of the sleeve (29) and being arranged towards the limit operating rod, and the other end being connected to the bottom surface of the sleeve (29) via a safety reset spring (28), and when the limit operating rod squeezes the safety reset column, the safety reset spring (28) is compressed; A first retaining ring and a second retaining ring are sleeved on the limit push rod, the first retaining ring is fixedly connected to the limit push rod, the second retaining ring is fixedly connected to the valve seat (2), and the second retaining ring is movably connected to the limit push rod, and a second energy storage spring (31) is sleeved on the limit push rod between the first retaining ring and the second retaining ring; A stopper (34) is fixedly connected to the limit push rod, a vertical displacement rod (35) and a lateral displacement rod (24) are vertically arranged below the limit push rod, a vertical rack is fixedly arranged on the vertical displacement rod (35), a lateral rack is fixedly arranged on the lateral displacement rod (24), and both the vertical displacement rod (35) and the lateral displacement rod (24) are slidably connected to the valve body (1), the vertical rack and the lateral rack are meshed with the same transmission gear (36), and the transmission gear (36) is rotatably arranged on the valve body (1); The stopper (34) is arranged toward the vertical displacement rod (35), and when the limit push rod slides on the valve body (1), the stopper (34) contacts the vertical displacement rod (35), and the vertical displacement rod (35) limits the sliding of the limit push rod; A roller (25) is arranged on one end of the lateral displacement rod (24) facing the limit chuck (4), and a third retaining ring and a fourth retaining ring (22) are sleeved on the other end, the third retaining ring is fixedly connected to the lateral displacement rod (24), the fourth retaining ring (22) is fixedly connected to the valve body (1), the fourth retaining ring (22) is movably connected to the lateral displacement rod (24), and the third retaining ring is arranged on the lateral displacement rod (24) between the fourth retaining ring (22) and the lateral rack, and a lateral return spring (23) is arranged on the upper step of the lateral displacement rod (24) between the third retaining ring and the fourth retaining ring (22). A protruding rod (26) is provided on a surface of the limit chuck (4) facing the lateral displacement rod (24); when the limit chuck (4) moves along with the valve stem (5) toward or away from the connecting hole, the protruding rod (26) squeezes the roller (25) when passing the roller (25), and pushes the lateral displacement rod (24) to slide in a direction away from the limit chuck (4).

6. A control method for an intelligent natural gas wellhead emergency shut-off valve as claimed in claim 5, characterized in that: During normal production, the valve body (1) is in an open state, the pressure value of the pressure switch (18) is set according to the safety range of the wellhead pressure, the pressure before the emergency shut-off valve is within the set value, the limit pin (17) is located at the bottom of the limit chuck (4), blocking the energy storage spring from pressing down the valve stem (5); the limit operating rod of the limit rod is in a non-pressed state, the limit safety rod is located on one side of the limit chuck, and the second energy storage spring (31) of the limiter push rod is in a non-compressed state; When the pressure before the emergency shut-off valve exceeds or falls below a set value, the pressure switch (18) controls the three-way valve (15) to operate, so that the natural gas pipeline before the inlet is connected to the air cavity of the piston (10); The gas pushes the piston (10) to move, driving the limit release gear (16) to rotate counterclockwise, pulling the two limit pins (17) away from each other, and the third energy storage spring (12) pushes the valve stem (5) to move downward, the valve core (3) blocks the communication hole, and the valve is closed; At the same time, the protruding rod (26) on the limit chuck (4) moves downward along with the valve stem (5), pushing the lateral displacement rod (24) to move leftward, driving the transmission gear (36) to rotate clockwise, driving the vertical displacement rod (35) to move downward via the vertical rack, and losing the position restriction on the limit push rod. The second energy storage spring (31) bounces the limit push rod to the left, and the limit operating rod is in a non-pressed state. When the valve is completely closed, the limit safety rod is above the limit chuck (4) to prevent the valve from opening due to high pressure. The natural gas wellhead fault is eliminated and the pressure returns to normal. The pressure switch (18) controls the three-way valve (15) to connect the venting pipeline and the air cavity of the piston (10), and the gas in the piston (10) is vented through the three-way valve (15), so as to prepare for the next emergency shutdown. The valve body (1) needs to be opened; first, an electric reset is required, and then the control motor (6) is started to drive the valve stem (5) to move upward to open the valve; Specifically, the manual reset button (32) or the electric reset button (33) is first pressed, and the manual or electric reset button (33) pushes the limit push rod to move leftward, pushes the limit operating rod to rotate clockwise, and moves the limit safety rod to one side of the limit chuck (4), releasing the restriction on the limit chuck (4); at the same time, the limit push rod is stuck by the vertical displacement rod (35) after moving to the right and cannot move to the right; at this time, the motor (6) is turned on or the hand wheel is rotated to drive the valve stem (5) to move upward and open the valve body (1). During the upward movement of the valve stem (5), the protruding rod (26) pushes the lateral displacement rod (24) to move leftward, the transmission gear (36) rotates clockwise, and the vertical displacement rod (35) moves downward, losing the position restriction on the limiter push rod. The second energy storage spring (31) bounces the limiter push rod to the left, the limiter is in a non-pressed state, and the lower end of the limit rod is on the left side of the limit chuck (4), and the normal production state is restored.

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