A mechanically re-openable airtight sealing valve, a special tool and a method of use

Abstract

This invention provides a mechanically reversible gas-tight valve, a special tool, and a method of use. The mechanically reversible gas-tight valve includes a cylinder with both ends for detachable connection to a tubing string. A push cylinder and an opening / closing mechanism are disposed within the cylinder. The push cylinder is axially movable along the cylinder and has two fixed working positions. By moving the push cylinder to different fixed working positions, the opening and closing of the opening / closing mechanism can be controlled, thereby controlling the opening and closing of the tubing string. This invention utilizes an axially movable push cylinder within the cylinder, allowing the opening and closing of the opening / closing mechanism to be achieved by controlling the push cylinder's movement to different fixed working positions, thus controlling the opening and closing of the tubing string. The moving push cylinder employs mechanical control, allowing the opening and closing mechanism to be repeatedly opened or closed. Furthermore, the cylinder can be disassembled and reused after use.

Description

Technical Field

[0001] This invention relates to the field of oil and gas well development technology, specifically to a mechanically reversible gas-tight valve, a special tool, and a method of use. Background Technology

[0002] Live well operations are an advanced downhole technology that involves running and pulling tubing or constructing wellheads while maintaining a certain pressure within the wellbore, without controlling the well or releasing pressure. Compared to traditional downhole operations, live well operations offer the advantage of maximizing the protection of oil and gas reservoirs and the environment, avoiding formation pollution caused by well control. Live well operations typically utilize plugs, which are fixed inside the tubing string to seal the tubing passage.

[0003] Currently, drop-and-retrieve plugs or tubing bridge plugs are commonly used for sealing. Drop-and-retrieve plugs are mostly made of rubber and are inserted directly into the wellbore to be sealed. However, during the sealing process, the plug's own elasticity is used to press the outer wall against the inner wall of the wellbore to achieve a seal. This makes installation and retrieval inconvenient, and the plug is generally unusable after one use. Tubing bridge plugs mainly use slips to bite into the tubing and seal the inner wall of the tubing through a compression rubber sleeve. Tubing bridge plugs can damage the tubing and are permanent devices. Their recovery and reuse are limited after use. Furthermore, drop-and-retrieve plugs or tubing bridge plugs are prone to shifting due to pressure, leading to seal failure. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a mechanically reversible airtight valve.

[0005] This invention provides a mechanically reversible gas-tight valve, comprising a cylinder, the two ends of which are detachably connected to an oil tubing string. The cylinder is provided with a push cylinder and an opening and closing mechanism. The push cylinder can move along the axial direction of the cylinder and has two fixed working positions. By moving the push cylinder to different fixed working positions, the opening and closing of the opening and closing mechanism can be controlled, thereby controlling the opening and closing of the oil tubing string.

[0006] This invention utilizes an axially movable pusher within the cylinder. By controlling the pusher's movement to different fixed working positions, the opening and closing mechanism can be activated, thereby controlling the opening and closing of the tubing string. The movable pusher is mechanically controlled, allowing the opening and closing mechanism to be repeatedly opened or closed. Furthermore, the cylinder can be disassembled and reused after use.

[0007] Furthermore, the cylindrical body includes an upper connector, a connecting sleeve, and a lower connector connected in sequence, the upper connector, the connecting sleeve, and the lower connector being arranged coaxially, the connecting sleeve and the lower connector being detachably connected, and the upper connector and the connecting sleeve being either detachably connected or an integral structure.

[0008] This invention facilitates the installation and disassembly of the cylinder and the installation of the push cylinder by setting the cylinder body into multiple sections.

[0009] Furthermore, the push cylinder is disposed inside the connecting sleeve, the opening and closing mechanism is disposed at one end of the push cylinder near the lower connector, a boss is provided on the cylinder wall of the push cylinder, and an upper locking groove and a lower locking groove are provided on the inner wall of the connecting sleeve to cooperate with the boss. The upper locking groove and the lower locking groove are used to axially limit the boss.

[0010] The inner wall of the push cylinder is provided with a groove for engaging with a special tool. The groove is used to engage with the special tool so that the push cylinder can be lifted or pressed down by the special tool, so that the boss is locked in the upper locking groove or the lower locking groove. When the boss is locked in the upper locking groove, the opening and closing mechanism is closed. When the boss is locked in the lower locking groove, the push cylinder pushes the opening and closing mechanism open, and the oil pipe column channel is opened.

[0011] This invention provides a boss, an upper locking groove, and a lower locking groove. When the boss is in the upper or lower locking groove, it corresponds to two fixed working positions of the push cylinder, ensuring that the push cylinder is not easily moved axially in the two fixed working positions. By setting a groove inside the push cylinder, a special tool can be used to lock in the groove, thereby using the special tool to lift or press the push cylinder up or down to achieve the switching of the two fixed working positions of the push cylinder.

[0012] Furthermore, the groove includes an upper groove and a lower groove. A first bearing surface is provided at the end of the upper groove away from the lower groove. The first bearing surface is used to bear the upward pulling force of the special tool. A first guide surface is provided at the end of the upper groove near the lower groove. The first guide surface is used to guide the special tool to move downward. A second guide surface is provided at the end of the lower groove near the upper groove. The second guide surface is used to guide the special tool to move upward. A second bearing surface is provided at the end of the lower groove away from the upper groove. The second bearing surface is used to bear the downward pressure of the special tool.

[0013] By setting upper and lower grooves, this invention can ensure that special tools can smoothly enter and exit the push cylinder and apply force to the push cylinder.

[0014] Furthermore, the boss is arranged on the outer wall of the lower groove, and the lower groove has multiple through holes along the circumferential direction.

[0015] The present invention reduces the rigidity of the lower groove by setting multiple through holes, so that when the pusher is lifted or pressed down, the lower groove can undergo slight radial deformation, thereby causing the boss to disengage from the lower locking groove or the upper locking groove.

[0016] Furthermore, the opening and closing mechanism includes a valve seat and a valve plate. The valve seat is cylindrical and coaxially arranged with the connecting sleeve. The outer periphery of the valve seat is sealed to the connecting sleeve. The lower end of the valve seat is rotatably connected to the valve plate via a pin. A torsion spring is provided on the pin. The torsion spring is used to automatically close the valve plate, so that the valve plate seals the lower opening of the valve seat.

[0017] This invention features an automatically closing valve plate. When the boss of the push cylinder is engaged in the upper locking groove, the push cylinder does not act on the valve plate, and the valve plate closes the lower opening of the valve seat. When the boss of the push cylinder is engaged in the lower locking groove, the push cylinder acts on the valve plate, and the valve plate is pushed open by the push cylinder, opening the lower opening of the valve seat.

[0018] Furthermore, the connecting sleeve has an annular mounting groove with a diameter larger than that of the push cylinder. The valve seat is disposed in the mounting groove, and the inner circumference of the valve seat fits against the outer circumference of the push cylinder. The bottom of the mounting groove is provided with a conical surface, and the valve seat abuts against the conical surface.

[0019] This invention improves the sealing performance between the valve seat and the connecting sleeve by setting an installation groove, in which the valve seat abuts against the conical surface of the installation groove.

[0020] Furthermore, the lower connector is connected to the inner wall of the connecting sleeve at one end. The lower connector has a first step on its end face near the connecting sleeve that mates with the lower end face of the push cylinder. When the boss is locked in the lower locking groove, the push cylinder abuts against the first step, so that the valve seat and valve plate are wrapped between the push cylinder and the connecting sleeve.

[0021] In this invention, the valve seat and valve plate are enclosed between the push cylinder and the connecting sleeve, which prevents the production medium from eroding the valve plate and causing valve plate failure. The push cylinder abuts against the first step, which prevents the push cylinder from being pushed further down and avoids the boss from disengaging from the lower locking groove.

[0022] Furthermore, an inclined fifth guide surface is provided on the inner wall of the upper connector. When the boss of the push cylinder is moved to the upper locking groove using a special tool, the fifth guide surface can guide the special tool to exit the push cylinder.

[0023] The present invention provides a fifth guide surface that can cooperate with the fourth guide surface of the special tool to guide the special tool out of the push cylinder.

[0024] Furthermore, the upper connector has a second step that mates with the upper end face of the push cylinder. When the boss is locked in the upper locking groove, the push cylinder abuts against the second step.

[0025] By providing a second step, this invention can prevent the push cylinder from being lifted further, thus avoiding the boss from disengaging from the upper locking groove.

[0026] Secondly, the present invention provides a special tool for use with a mechanically reversible airtight valve, comprising a tension cylinder, wherein the tension cylinder is provided with a telescopic block and a spring connected to the telescopic block, the telescopic block can extend and retract radially along the tension cylinder, and the telescopic block is provided axially with a third bearing surface and a third guide surface and a fourth guide surface for facilitating the withdrawal of the tension cylinder from the push cylinder, the third bearing surface is used to cooperate with the first bearing surface to lift the push cylinder or cooperate with the second bearing surface to press the push cylinder down, the fourth guide surface is used to cooperate with the fifth guide surface, and the third guide surface is used to cooperate with the second guide surface.

[0027] The special tool of the present invention is provided with a third bearing surface, a third guide surface, and a fourth guide surface. The third guide surface and the fourth guide surface enable the special tool to smoothly exit the push cylinder, and the third bearing surface enables the special tool to apply force to the first bearing surface and the second bearing surface.

[0028] Thirdly, the present invention provides a method for using a mechanically reversible gas-tight valve, comprising:

[0029] When it is necessary to close the opening and closing mechanism, insert the end of the special tool near the third guide surface into the push cylinder, so that the telescopic block is stuck in the upper groove. Lift the special tool, and the third bearing surface will apply the lifting force to the first bearing surface to drive the push cylinder to move upward, so that the boss of the push cylinder moves from the lower locking groove to the upper locking groove. Under the action of the torsion spring, the valve plate closes the lower opening of the valve seat.

[0030] When the opening and closing mechanism needs to be opened, insert the end of the special tool near the third bearing surface into the push cylinder, so that the telescopic block is stuck in the lower groove. Press down the special tool, and the third bearing surface will apply the downward force to the second bearing surface, causing the push cylinder to move downward, so that the boss of the push cylinder moves from the upper locking groove to the lower locking groove. Under the action of the push cylinder, the valve plate rotates to open the lower opening of the valve seat.

[0031] The special tool of this invention can lift or press down the push cylinder by inserting different ends into it.

[0032] The beneficial effects of this invention are as follows: This invention uses tubing for lowering, that is, the cylinder is part of the tubing string. It can be repeatedly opened and closed according to the needs of later production, which is convenient to operate and does not damage the tubing string. It uses an all-metal valve plate for sealing, which has good load-bearing capacity and sealing performance and strong environmental adaptability. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the mechanically reversible gas-tight valve of the present invention in the closed state;

[0034] Figure 2 This is a schematic diagram of the pusher cylinder of the present invention;

[0035] Figure 3 This is a schematic diagram of the connecting sleeve of the present invention;

[0036] Figure 4 This is a schematic diagram of the mechanically reversible gas-tight valve of the present invention in the open state.

[0037] Figure 5 for Figure 1 Enlarged view of point A in the middle;

[0038] Figure 6 This is a schematic diagram showing the state of the push cylinder when the special tool of this invention is pressed down;

[0039] Figure 7 This is a schematic diagram showing the state of the tool used in this invention when lifting the push cylinder.

[0040] Reference numerals: 1. Upper connector; 2. Connecting sleeve; 3. Lower connector; 4. Push cylinder; 5. Opening and closing mechanism; 6. Boss; 7. Upper locking groove; 8. Lower locking groove; 9. Upper groove; 10. Lower groove; 11. First bearing surface; 12. First guide surface; 13. Second guide surface; 14. Second bearing surface; 15. Through hole; 16. Valve seat; 17. Valve plate; 18. Torsion spring; 19. Pin; 20. Mounting groove; 21. First step; 22. Second step; 23. Conical surface; 24. Fifth guide surface; 25. Upper cylinder; 26. Lower cylinder; 27. Connecting shaft; 28. Upper limit block; 29. ​​Lower limit block; 30. Telescopic block; 31. Spring; 32. Upper protrusion; 33. Lower protrusion; 34. Third bearing surface; 35. Third guide surface; 36. Fourth guide surface. Detailed Implementation

[0041] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0042] like Figure 1As shown, a mechanically reusable airtight valve includes an upper connector 1, a connecting sleeve 2, and a lower connector 3 connected in sequence. The upper connector 1, connecting sleeve 2, and lower connector 3 are coaxially arranged and are all detachably connected by threads. A push cylinder 4 is movably disposed within the connecting sleeve 2 and can move axially along the connecting sleeve 2. An opening and closing mechanism 5 is disposed below the push cylinder 4. The opening and closing mechanism 5 includes a valve seat 16 and a valve plate 17. The lower end of the valve seat 16 and the valve plate 17 are connected by a pin 19 and a torsion spring 18. Without external force, the valve plate 17 will press tightly against the lower end face of the valve seat 16 under the action of the torsion spring 18, thereby closing the lower end opening of the valve seat 16. It can be understood that by pushing the push cylinder 4 downward, the push cylinder 4 can push the valve plate 17 open, and the opening and closing mechanism 5 can be opened.

[0043] like Figure 2 As shown, the push cylinder 4 has an upper groove 9 and a lower groove 10. The upper end of the upper groove 9 has a horizontal first bearing surface 11, and the lower end of the upper groove 9 has an inwardly inclined and downward-facing first guide surface 12. The lower end of the lower groove 10 has a horizontal second bearing surface 14, and the upper end of the upper groove 9 has an inwardly inclined and upward-facing second guide surface 13. The first guide surface 12... Figure 2 The cross-section is inverted V-shape, and the second guide surface 13 is in Figure 2 The cross-section is V-shaped. The lower trench 10 also has multiple elongated through holes 15, which are arranged along the axial direction.

[0044] The outer wall of the pusher cylinder 4 is provided with an annular protrusion, which is located at the lower groove 10.

[0045] like Figure 3 As shown, the upper outer diameter of the connecting sleeve 2 is small, used to connect to the inner wall of the upper connector 1, and the lower outer diameter of the connecting sleeve 2 is large, used to connect to the outer wall of the lower connector 3, that is, the inner wall of the connecting sleeve 2 is connected to the outer wall of the lower connector 3. The connecting sleeve 2 has an upper locking groove 7 and a lower locking groove 8. The upper locking groove 7 is near the upper end of the connecting sleeve 2, and the lower locking groove 8 is near the middle of the connecting sleeve 2. The upper locking groove 7 or the lower locking groove 8 can cooperate with the protrusion of the push cylinder 4 to axially limit the push cylinder 4. The upper locking groove 7 and the lower locking groove 8 correspond to two fixed working positions of the push cylinder 4, respectively.

[0046] A mounting groove 20 is provided on the inner wall near the lower part of the connecting sleeve 2. The mounting groove 20 is used to install the opening and closing mechanism 5. The bottom of the mounting groove 20 is provided with a conical surface 23. The valve seat 16 is installed in the mounting groove 20 by threads. The upper end of the valve seat 16 is flush with the bottom of the mounting groove 20 (i.e., Figure 3 The upper end of the mounting groove 20 abuts against the valve seat 16, improving the sealing between the valve seat 16 and the connecting sleeve 2.

[0047] like Figure 4As shown, the upper end face of the lower connector 3 is provided with a first step 21. When the boss 6 of the push cylinder 4 is stuck in the lower locking groove 8, the lower end face of the push cylinder 4 abuts against the first step 21, so that the valve seat 16 and the valve plate 17 are wrapped between the push cylinder 4 and the connecting sleeve 2, which can prevent the production medium from eroding the valve plate 17 and causing the valve plate 17 to fail. The first step 21 can also prevent the push cylinder 4 from being pushed down further, and prevent the boss 6 from disengaging from the lower locking groove 8.

[0048] like Figure 5 As shown, a second step 22 is provided on the inner wall of the upper connector 1. When the boss 6 of the push cylinder 4 is locked in the upper locking groove 7, the upper end face of the push cylinder 4 abuts against the second step 22, which can prevent the push cylinder 4 from being lifted further and prevent the boss 6 from disengaging from the upper locking groove 7.

[0049] An inclined fifth guide surface 24 is provided on the inner wall of the upper connector 1. When the boss 6 of the push cylinder 4 is moved to the upper locking groove 7 using a special tool, the fifth guide surface 24 can guide the special tool to exit the push cylinder.

[0050] This invention provides a fifth guide surface that engages with the fourth guide surface of a special tool to guide the special tool out of the push cylinder.

[0051] like Figure 6 As shown, the special tool includes a tensioning cylinder, which comprises an upper cylinder 25 and a lower cylinder 26. A connecting shaft 27 is coaxially arranged inside the lower cylinder 26. One end of the connecting shaft 27 extends out of the upper opening of the lower cylinder 26 and is threadedly connected to the inner wall of the upper cylinder 25. The other end is integrally connected to the lower cylinder 26. An upper limit block 28 is fixedly arranged at the lower end of the upper cylinder 25. The upper limit block 28 is annular. A lower limit block 29 is arranged on the connecting shaft 27, which is positioned above the lower cylinder 26. The lower limit block 29 is annular. Multiple telescopic blocks 30 are evenly arranged around the outer periphery of the connecting shaft 27. A spring 3 is arranged between the telescopic blocks 30 and the connecting shaft 27. 1. Multiple telescopic blocks 30 are located between the lower limit block 29 and the upper limit block 28. The upper and lower ends of the telescopic blocks 30 are respectively attached to the upper limit block 28 and the lower limit block 29, so that the upper limit block 28 and the lower limit block 29 can restrict the axial movement of the telescopic blocks 30. The upper and lower ends of the telescopic blocks 30 are respectively provided with an upper protrusion 32 and a lower protrusion 33. The upper protrusion 32 and the lower protrusion 33 are respectively located inside the upper limit block 28 and the lower limit block 29, that is, on the side close to the connecting shaft 27. A gap is provided between the upper protrusion 32 and the upper limit block 28, and a gap is provided between the lower protrusion 33 and the lower limit block 29, so that the telescopic blocks 30 can reciprocate radially.

[0052] In this embodiment, two telescopic blocks 30 are symmetrically arranged. Each telescopic block 30 is semi-cylindrical, and a third guide surface 35 is inclinedly arranged on the outer periphery of the telescopic block 30 near its upper end. Figure 6The third guide surface 35 has a V-shaped cross-section. A third bearing surface 34 is provided in the middle of the telescopic block 30. The third bearing surface 34 is used to cooperate with the first bearing surface to lift the push cylinder or to cooperate with the second bearing surface to press the push cylinder down. A fourth guide surface 36 is provided at an incline near the lower end of the outer periphery of the telescopic block 30. Figure 6 The cross-section of the fourth guide surface 36 is inverted V-shape.

[0053] It is understandable that when the lower end of the special tool (i.e., the end near the fourth guide surface 36) enters the push cylinder 4, it... Figure 6 When the special tool enters the push cylinder 4, under the guidance of the first guide surface 12, it can smoothly pass through the upper groove 9 and enter the lower groove 10. After entering the lower groove 10, under the guidance of the fourth guide surface 36, the telescopic block 30 continues to move downward, so that the third bearing surface 34 of the telescopic block 30 is stuck in the lower groove 10. At this time, the second bearing surface 14 and the third bearing surface 34 are in contact. By pressing down the special tool, the downward pressure of the third bearing surface 34 can act on the second bearing surface 14, thereby pressing down the push cylinder 4. After the pressing is completed, the special tool is retracted. Under the action of the second guide surface 13, the special tool can move upward, causing the telescopic block 30 to leave the lower groove 10. After the telescopic block 30 enters the upper groove 9, under the action of the third guide surface 35, the telescopic block 30 can leave the upper groove 9, thereby realizing the retraction of the special tool.

[0054] When the upper end of the special tool (i.e., the end closest to the third guide surface 35) enters the push cylinder 4, it is... Figure 7 When the special tool enters the push cylinder 4, the telescopic block 30 of the special tool enters the upper groove 9. At this time, the first bearing surface 11 and the third bearing surface 34 are in contact. By lifting the special tool, the lifting force of the third bearing surface 34 can act on the first bearing surface 11, thereby lifting the push cylinder 4. After the lifting is completed, the special tool is retracted. After the lifting is completed, the fourth guide surface 36 of the telescopic block 30 is in contact with the fifth guide surface 24 of the upper connector 1. During the process of continuing to lift the special tool, the fifth guide surface 24 squeezes the fourth guide surface 36, causing the telescopic block 30 to retract inward, thereby causing the first bearing surface 11 and the third bearing surface 34 to be misaligned, thereby realizing the retraction of the special tool.

[0055] The method of using this mechanically reversible gas-tight valve includes:

[0056] like Figure 1 As shown, under normal production conditions, the boss 6 on the push cylinder 4 is located in the lower locking groove of the connecting sleeve 2, which can keep the push cylinder 4 in an axial position. At this time, the valve plate 17 is always in the open state, the production channel is open, and the valve seat 16 and the valve plate 17 are located in the annular space of the push cylinder 4 and the connecting sleeve 2, which can effectively prevent the sealing surface from being eroded by the production medium and causing failure.

[0057] When it is necessary to close the opening and closing mechanism 5, insert the end of the special tool near the third guide surface 35 into the push cylinder 4, so that the telescopic block 30 is locked in the upper groove 9. Lift the special tool, and the third bearing surface 34 will exert the lifting force on the first bearing surface 11 to drive the push cylinder 4 to move upward, so that the boss 6 of the push cylinder 4 moves from the lower locking groove 8 to the upper locking groove 7. Under the action of the torsion spring 18, the valve plate 17 closes the lower opening of the valve seat 16, and the production channel is closed.

[0058] When the opening and closing mechanism 5 needs to be opened, the end of the special tool near the third bearing surface 34 is inserted into the push cylinder 4, so that the telescopic block 30 is stuck in the lower groove 10. Press down the special tool, and the third bearing surface 34 applies the downward force to the second bearing surface 14, causing the push cylinder 4 to move downward, so that the boss 6 of the push cylinder 4 moves from the upper locking groove 7 to the lower locking groove 8. Under the action of the push cylinder 4, the valve plate 17 rotates to open the lower opening of the valve seat 16, and the production channel is opened.

[0059] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A mechanically reversible airtight valve, characterized in that: Includes a cylinder, the two ends of which are detachably connected to the tubing string. The cylinder is provided with a push cylinder (4) and an opening and closing mechanism (5). The push cylinder (4) can move along the cylinder axis. The push cylinder (4) is provided with two fixed working positions. By moving the push cylinder (4) to different fixed working positions, the opening and closing of the opening and closing mechanism (5) can be controlled, thereby controlling the opening and closing of the tubing string. The cylinder includes an upper connector (1), a connecting sleeve (2), and a lower connector (3) connected in sequence. The upper connector (1), the connecting sleeve (2), and the lower connector (3) are arranged coaxially. The connecting sleeve (2) and the lower connector (3) are detachably connected. The upper connector (1) and the connecting sleeve (2) are either detachably connected or an integral structure. The push cylinder (4) is set inside the connecting sleeve (2), and the opening and closing mechanism (5) is set at one end of the push cylinder (4) near the lower connector (3). A boss (6) is provided on the cylinder wall of the push cylinder (4), and an upper locking groove (7) and a lower locking groove (8) that cooperate with the boss (6) are provided on the inner wall of the connecting sleeve (2). The upper locking groove (7) and the lower locking groove (8) are used to axially limit the boss (6). The inner wall of the push cylinder (4) is provided with a groove for engaging with a special tool. The groove is used to engage with the special tool so that the push cylinder (4) can be lifted or pressed down by the special tool, so that the boss (6) is locked in the upper locking groove (7) or the lower locking groove (8). When the boss (6) is locked in the upper locking groove (7), the opening and closing mechanism (5) is closed. When the boss (6) is locked in the lower locking groove (8), the push cylinder (4) pushes the opening and closing mechanism (5) open, and the oil pipe column channel is opened. The groove includes an upper groove (9) and a lower groove (10). A first bearing surface (11) is provided at the end of the upper groove (9) away from the lower groove (10). The first bearing surface (11) is used to bear the upward pulling force of the special tool. A first guide surface (12) is provided at the end of the upper groove (9) near the lower groove (10). The first guide surface (12) is used to guide the special tool to move downward. A second guide surface (13) is provided at the end of the lower groove (10) near the upper groove (9). The second guide surface (13) is used to guide the special tool to move upward. A second bearing surface (14) is provided at the end of the lower groove (10) away from the upper groove (9). The second bearing surface (14) is used to bear the downward pressure of the special tool. The opening and closing mechanism (5) includes a valve seat (16) and a valve plate (17). The valve seat (16) is cylindrical and is coaxially arranged with the connecting sleeve (2). The outer periphery of the valve seat (16) is sealed to the connecting sleeve (2). The lower end of the valve seat (16) is rotatably connected to the valve plate (17) through a pin (19). A torsion spring (18) is provided on the pin (19). The torsion spring (18) is used to automatically close the valve plate (17) so that the valve plate (17) seals the lower opening of the valve seat (16). The upper connector (1) has a fifth guide surface (24) on its inner wall. When the boss (6) of the push cylinder (4) is moved to the upper locking groove (7) using a special tool, the fifth guide surface (24) can guide the special tool to exit the push cylinder (4).

2. The mechanically reversible airtight valve according to claim 1, characterized in that: The boss (6) is arranged on the outer wall of the lower groove (10), and the lower groove (10) has a plurality of through holes (15) in the circumferential direction.

3. The mechanically reversible airtight valve according to claim 1, characterized in that: The lower connector (3) is connected to the inner wall of the connecting sleeve (2) at one end. The lower connector (3) has a first step (21) on the end face of the connecting sleeve (2) that mates with the lower end face of the push cylinder (4). When the boss (6) is locked in the lower locking groove (8), the push cylinder (4) abuts against the first step (21), so that the valve seat (16) and the valve plate (17) are wrapped between the push cylinder (4) and the connecting sleeve (2).

4. A special tool for use with the mechanically reversible airtight valve according to any one of claims 1 to 3, characterized in that: The device includes a tensioning cylinder, on which a telescopic block (30) and a spring (31) connected to the telescopic block (30) are provided. The telescopic block (30) can extend and retract radially along the tensioning cylinder. The telescopic block (30) is provided axially with a third bearing surface (34) and a third guide surface (35) and a fourth guide surface (36) to facilitate the tensioning cylinder's exit from the push cylinder (4). The third bearing surface (34) is used to cooperate with the first bearing surface (11) to lift the push cylinder (4) or to cooperate with the second bearing surface (14) to press the push cylinder (4) down. The fourth guide surface (36) is used to cooperate with the fifth guide surface (24). The third guide surface (35) is used to cooperate with the second guide surface (13).

5. A method of using a mechanically reversible airtight valve as described in any one of claims 1 to 3, characterized in that, The tool described in claim 4, when used in conjunction with other tools, includes: When it is necessary to close the opening and closing mechanism (5), insert the end of the special tool close to the third guide surface (35) into the push cylinder (4), so that the telescopic block (30) is stuck in the upper groove (9). Lift the special tool, and the third bearing surface (34) will apply the lifting force to the first bearing surface (11) to drive the push cylinder (4) to move upward, so that the boss (6) of the push cylinder (4) moves from the lower locking groove (8) to the upper locking groove (7). The valve plate (17) closes the lower opening of the valve seat (16) under the action of the torsion spring (18). When the opening and closing mechanism (5) needs to be opened, the end of the special tool close to the third bearing surface (34) is inserted into the push cylinder (4), so that the telescopic block (30) is stuck in the lower groove (10). The special tool is pressed down, and the third bearing surface (34) applies the downward force to the second bearing surface (14), causing the push cylinder (4) to move downward, so that the boss (6) of the push cylinder (4) moves from the upper locking groove (7) to the lower locking groove (8). Under the action of the push cylinder (4), the valve plate (17) rotates to open the lower opening of the valve seat (16).

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