Protection device for wellhead Christmas tree valve

Abstract

The invention relates to the technical field of Christmas tree valves, in particular to a protection device for a wellhead Christmas tree valve, which comprises an upper valve main body and a lower valve main body, each of the upper valve main body and the lower valve main body comprises a valve body, a brake block and a control structure; the control structure comprises a cover plate detachably connected with the valve body, a receding groove is formed in one side of the cover plate, a blocking piece is arranged in the receding groove, a threaded sleeve is fixedly arranged in the blocking piece in a sleeved mode, a lead screw is in threaded connection with the interior of the threaded sleeve, one end of the lead screw is fixedly connected with the brake block, and a handle is fixedly connected to the outer wall of the threaded sleeve. According to the invention, when the upper valve main body leaks, the pressure in the shell is increased, and a pressure medium pushes the first piston to move through the air inlet hole, so that the limiting pin is separated from the pin groove of the limiting block, and the restrained balancing weight is released. The balancing weight drives the rack to move downwards under the action of gravity, the gear ring and the threaded sleeve fixed to the gear ring are driven to rotate, and then the gate block is driven through the lead screw to rapidly close the lower valve body.

Description

Technical Field

[0001] This invention relates to the field of wellhead tree valve technology, specifically a protection device for wellhead tree valves. Background Technology

[0002] In oil and gas extraction, the wellhead Christmas tree is the core equipment for controlling oil and gas flow. Its main valve, acting as the "master gate" for well control, directly relates to production safety and environmental risks. Conventional Christmas trees typically have two main valves connected in series: the upper main valve for daily production control and the lower main valve as an emergency backup. When the upper main valve leaks due to prolonged use, corrosion, or sealing failure, the high-pressure medium inside the well must be quickly isolated to prevent major accidents such as blowouts, fires, or environmental pollution.

[0003] Currently, the commonly used technical solution relies on manual judgment and operation. That is, after discovering a leak or abnormal pressure in the upper main valve, the operator must manually close the lower main valve to achieve isolation. However, this method has significant drawbacks: Response lag: There is a time lag between the discovery of a leak and the arrival of personnel on site and the completion of operations. In the high-pressure, high-risk wellhead environment, the leak may expand rapidly during this period, leading to an escalation of the accident.

[0004] Reliance on manpower: In severe weather, at night, or in sudden emergencies, the speed of personnel response and operational safety cannot be guaranteed.

[0005] No active protection: The existing valves themselves do not have the function of automatically triggering the backup valve to close based on the upstream leakage status, and the system as a whole lacks active safety interlocking capability. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention proposes a protection device for wellhead tree valves.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a protection device for a wellhead tree valve, comprising an upper valve body and a lower valve body; both the upper valve body and the lower valve body include a valve body, a gate block, and a control structure; The control structure includes a cover plate detachably connected to the valve body. A relief groove is provided on one side of the cover plate. A blocking component is provided in the relief groove. A threaded sleeve is fixedly fitted inside the blocking component. A lead screw is threadedly connected inside the threaded sleeve. One end of the lead screw is fixedly connected to the gate block. A handle is fixedly connected to the outer wall of the threaded sleeve. Both the upper valve body and the lower valve body are fixedly fitted with housings on their outer walls, and the two housings are fixedly connected by screws and nuts. The blocking component of the upper valve body is a fixed ring, and the blocking component of the lower valve body is a toothed ring. A toothed rack is provided on one side of the toothed ring. One end of the toothed rack passes through the cover plate and extends to the outside and is fixedly connected to a counterweight. A limit block is fixedly connected to the side wall of the counterweight. One end of the limit block passes through the housing and extends into the housing of the upper valve body. A triggering mechanism is fixedly connected to the inner wall of the upper valve body housing. The triggering mechanism cooperates with the limiting block and is used to release the limiting block when the pressure inside the housing increases. The triggering mechanism is provided with an adjustment component to adjust the sensitivity of the triggering mechanism.

[0008] Preferably, the triggering mechanism includes a sleeve fixedly connected to the housing, a first piston slidably connected inside the sleeve, a spring provided on one side of the first piston, a limit pin fixedly connected to the side wall of the first piston, a pin groove opened on the side wall of the limit block, one end of the limit pin passing through the sleeve and extending into the pin groove; an air inlet is opened on the side wall of the sleeve, and an exhaust port communicating with the upper valve body housing is opened at the bottom; when the pressure inside the housing increases, gas enters the sleeve through the air inlet, pushing the first piston to move and causing the limit pin to disengage from the pin groove.

[0009] Preferably, the adjusting assembly includes a second piston, with a stud threadedly connected to one side of the sleeve, one end of the stud penetrating the sleeve and rotatably connected to the second piston; by rotating the stud, the position of the second piston can be adjusted, thereby changing the degree of spring compression.

[0010] Preferably, the side wall of the housing is provided with a maintenance control operation port, and a sealed door that is detachably connected to the housing is provided on one side of the maintenance control operation port.

[0011] Preferably, a sealing plate is provided on one side of the relief groove, and the sealing plate is detachably connected to the cover plate.

[0012] Preferably, the weight of the counterweight is set to be sufficient to press the rack down and drive the gear ring to rotate.

[0013] Preferably, the spring is located between the first piston and the second piston.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. Achieves fully automatic emergency shutdown with rapid response: By setting up a linkage mechanism consisting of a housing, a triggering mechanism including a sleeve, a first piston, a spring, a limit pin, a counterweight, a rack, and a gear ring, the pressure signal generated by leakage in the upper valve is creatively converted into a mechanical triggering action. When leakage occurs in the upper valve body, the pressure inside its housing increases, and the pressure medium pushes the first piston through the air inlet, causing the limit pin to disengage from the pin groove of the limit block, thereby releasing the constrained counterweight. Under the action of gravity, the counterweight drives the rack downward, driving the gear ring and the threaded sleeve fixed to it to rotate, which in turn drives the gate block to quickly close the lower valve body through the screw. The entire process requires no manual intervention, and the response time from the occurrence of leakage to the closure of the lower valve is extremely short, greatly curbing the escalation of the accident.

[0015] 2. Equipped with trigger sensitivity adjustment function and strong adaptability: The integrated adjustment components of the device include a second piston and a stud, allowing operators to preset the trigger pressure threshold according to the actual wellhead conditions, such as the working pressure range and medium characteristics. By rotating the stud to adjust the position of the second piston and change the pre-compression of the spring, the pressure required to push the first piston can be adjusted. This allows the device to flexibly adapt to the safety control requirements of different oilfields and well conditions, avoiding false triggering or delayed triggering, and ensuring the accuracy and reliability of protection actions.

[0016] 3. Compact and reliable structure, easy maintenance: All automatic triggering and actuation mechanisms are integrated within the valve's external housing, without altering the original valve's internal structure or pressure-bearing boundaries, resulting in low safety risks. The housing itself provides additional physical protection for the valve. Furthermore, the inspection and control ports and sealing doors on the housing allow for convenient inspection, testing, reset, or manual operation of the internal mechanisms without interrupting production, making daily maintenance and emergency management convenient and efficient.

[0017] 4. Enhanced inherent safety level of wellhead safety system: This device adds an independent, physically based automatic safety barrier to the wellhead. Even in extreme cases of sudden severe leakage from upstream valves, it can automatically activate as a last line of defense, effectively isolating the risk source, buying valuable time for emergency repairs, and significantly reducing the probability of major safety and environmental accidents such as blowouts, fires, and explosions. It has significant safety and economic value. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a cross-sectional structural diagram of the present invention; Figure 3 for Figure 2 Enlarged structural diagram at point A in the middle; Figure 4 for Figure 2 Enlarged structural diagram at point B; Figure 5 for Figure 2 Enlarged structural diagram at point C; Figure 6 is Figure 4 Enlarged structural diagram at point D; Figure 7 is a partial structural schematic diagram of the present invention.

[0019] In the diagram: 1. Valve body; 2. Gate block; 3. Cover plate; 4. Relief groove; 5. Threaded sleeve; 6. Lead screw; 7. Handle; 8. Housing; 9. Screw; 10. Nut; 11. Retaining ring; 12. Gear ring; 13. Rack; 14. Counterweight; 15. Limiting block; 16. Sleeve; 17. First piston; 18. Spring; 19. Limiting pin; 20. Pin groove; 21. Air inlet; 22. Exhaust port; 23. Second piston; 24. Stud; 25. Inspection and control port; 26. Sealing door; 27. Sealing plate. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] Please see Figures 1 to 7 A protective device for wellhead tree valves includes an upper valve body and a lower valve body; both the upper valve body and the lower valve body include a valve body 1, a gate block 2, and a control structure. The control structure includes a cover plate 3 that is detachably connected to the valve body 1. A relief groove 4 is provided on one side of the cover plate 3. A blocking component is provided in the relief groove 4. A threaded sleeve 5 is fixedly sleeved in the blocking component. A screw rod 6 is threadedly connected in the threaded sleeve 5. One end of the screw rod 6 is fixedly connected to the gate block 2. A handle 7 is fixedly connected to the outer wall of the threaded sleeve 5. Both the upper valve body and the lower valve body are fixedly fitted with housings 8 on their outer walls, and the two housings 8 are fixedly connected by screws 9 and nuts 10. The blocking component of the upper valve body is a fixed ring 11, and the blocking component of the lower valve body is a toothed ring 12. A toothed ring 13 is provided on one side of the toothed ring 12. One end of the toothed ring 13 passes through the cover plate 3 and extends to the outside and is fixedly connected to a counterweight 14. A limit block 15 is fixedly connected to the side wall of the counterweight 14. One end of the limit block 15 passes through the housing 8 and extends into the housing 8 of the upper valve body. A triggering mechanism is fixedly connected to the inner wall of the housing 8 of the upper valve body. The triggering mechanism cooperates with the limit block 15 and is used to release the limit block 15 when the pressure inside the housing 8 increases. The triggering mechanism is equipped with an adjustment component to adjust the sensitivity of the triggering mechanism.

[0022] As shown in the above structure, when the upper valve body leaks, the leaking medium enters its housing 8, causing an increase in internal pressure. This pressure signal is sensed by the trigger mechanism, which releases the constraint on the limit block 15. Once the constraint is released, the counterweight 14 automatically falls under the action of gravity, driving the toothed ring 12 and threaded sleeve 5 of the lower valve body to rotate through the rack 13, thereby pushing the screw 6 and gate block 2 downward into the valve seat, thus realizing the automatic emergency closure of the lower valve body; achieving a fully automatic and rapid emergency response to leakage faults in the main valve of the wellhead. The leakage pressure signal is directly converted into a mechanical closing action, requiring no manual intervention or external energy, fundamentally overcoming the drawbacks of traditional methods such as delayed response and reliance on manpower, significantly improving the inherent safety level of the wellhead, and buying critical time for accident handling.

[0023] Furthermore, the triggering mechanism includes a sleeve 16 fixedly connected to the housing 8. A first piston 17 is slidably connected inside the sleeve 16. A spring 18 is provided on one side of the first piston 17. A limit pin 19 is fixedly connected to the side wall of the first piston 17. A pin groove 20 is opened on the side wall of the limit block 15. One end of the limit pin 19 passes through the sleeve 16 and extends into the pin groove 20. An air inlet 21 is opened on the side wall of the sleeve 16, and an exhaust port 22 communicating with the upper valve body housing 8 is opened at the bottom. When the pressure inside the housing 8 increases, gas enters the sleeve 16 through the air inlet 21, pushing the first piston 17 to move and causing the limit pin 19 to disengage from the pin groove 20. The pressure medium inside the housing 8 enters the sleeve 16 through the air inlet 21 and acts on the first piston 17. When the pressure overcomes the preload of the spring 18, it pushes the first piston 17 and the limit pin 19 fixed thereto to move until the limit pin 19 completely exits from the pin groove 20 of the limit block 15, thereby releasing the limit block 15.

[0024] Furthermore, the adjustment assembly includes a second piston 23, and a stud 24 is threadedly connected to one side of the casing 16. One end of the stud 24 passes through the casing 16 and is rotatably connected to the second piston 23. By rotating the stud 24, the position of the second piston 23 can be adjusted, thereby changing the compression degree of the spring 18. By rotating the stud 24, the second piston 23 can be driven to move axially within the casing 16. The displacement of the second piston 23 directly changes the initial compression of the spring 18, i.e., the preload. The greater the preload, the higher the pressure threshold required for the triggering mechanism to operate; thus, precise and continuous adjustment of the device's triggering pressure sensitivity is achieved. This allows the device to adapt to wellhead conditions with different working pressures and media characteristics, avoiding false triggering caused by pressure fluctuations, and ensuring timely operation in the event of a real leak, greatly enhancing the applicability and reliability of the device.

[0025] Furthermore, a maintenance control operation port 25 is provided on the side wall of the housing 8, and a sealing door 26 is provided on one side of the maintenance control operation port 25 that is detachably connected to the housing 8. By opening the sealing door 26, the operator can directly contact and operate the internal components such as the rack 13 and the counterweight 14 from the maintenance control operation port 25, and can also directly open and close the upper valve body.

[0026] Furthermore, a sealing plate 27 is provided on one side of the relief groove 4, and the sealing plate 27 is detachably connected to the cover plate 3; the sealing plate 27 covers the outside of the relief groove 4 to prevent external debris and corrosive media from entering the moving parts of the control structure.

[0027] Furthermore, the weight of the counterweight 14 is set to press the rack 13 down and drive the gear ring 12 to rotate; when the limit block 15 is released, the counterweight 14 relies on its own weight as the sole driving force to pull down the rack 13, driving the gear ring 12 to rotate through gear and rack meshing; using gravity as the driving energy ensures the absolute reliability and independence of the shut-off action. No external power source such as electricity, hydraulics, or pneumatics is required, ensuring the effective execution of the emergency shut-off function even in extreme situations such as a complete power outage at the well site.

[0028] Furthermore, the spring 18 is located between the first piston 17 and the second piston 23; the spring 18 is constrained between the first piston 17 and the second piston 23. The position of the second piston 23 determines the initial compression state of the spring 18 and the force exerted on the first piston 17.

[0029] In this invention, when the upper valve body of the oil well tree leaks, the leaking medium enters its outer housing 8, causing the pressure to rise; this pressure pushes the first piston 17 to compress the spring 18 and move through the air inlet 21 of the triggering mechanism, causing the limiting pin 19 connected to the first piston to disengage from the pin groove 20 of the upper limit block 15 of the counterweight block 14. The unconstrained counterweight pulls down the rack 13 under the action of gravity, driving the toothed ring 12 and threaded sleeve 5 on the lower valve body to rotate, and then pushes the gate block 2 into the valve seat through the screw 6, thereby realizing the fully automatic emergency closure of the lower valve body; The entire process is triggered by leakage pressure, driven by gravity, requiring no external power or human intervention, and the trigger pressure sensitivity can be preset by adjusting the components; During adjustment, rotating the stud 24 drives the second piston 23 to move axially within the casing 16. The displacement of the second piston 23 directly changes the initial compression of the spring 18, i.e., the preload. The greater the preload, the higher the pressure threshold required for the triggering mechanism to operate; this achieves precise and continuous adjustment of the device's triggering pressure sensitivity. This allows the device to adapt to wellhead conditions with different working pressures and media characteristics, avoiding false triggering caused by pressure fluctuations, and ensuring timely action in the event of a genuine leak, greatly enhancing the device's applicability and reliability.

[0030] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A protective device for a wellhead tree valve, comprising an upper valve body and a lower valve body; both the upper valve body and the lower valve body include a valve body (1), a gate block (2), and a control structure, characterized in that: The control structure includes a cover plate (3) detachably connected to the valve body (1). A relief groove (4) is provided on one side of the cover plate (3). A blocking member is provided in the relief groove (4). A threaded sleeve (5) is fixedly sleeved in the blocking member. A screw rod (6) is threadedly connected in the threaded sleeve (5). One end of the screw rod (6) is fixedly connected to the gate block (2). A handle (7) is fixedly connected to the outer wall of the threaded sleeve (5). The outer walls of both the upper valve body and the lower valve body are fixedly fitted with housings (8), and the two housings (8) are fixedly connected to the nuts (10) by screws (9); The blocking component of the upper valve body is a fixed ring (11), and the blocking component of the lower valve body is a toothed ring (12). A toothed rack (13) is provided on one side of the toothed ring (12). One end of the toothed rack (13) passes through the cover plate (3) and extends to the outside and is fixedly connected to a counterweight (14). A limit block (15) is fixedly connected to the side wall of the counterweight (14). One end of the limit block (15) passes through the housing (8) and extends into the housing (8) of the upper valve body. A triggering mechanism is fixedly connected to the inner wall of the housing (8) of the upper valve body. The triggering mechanism cooperates with the limiting block (15) to release the limiting block (15) when the pressure inside the housing (8) increases. The triggering mechanism is provided with an adjustment component to adjust the sensitivity of the triggering mechanism.

2. The protection device according to claim 1, characterized in that: The triggering mechanism includes a sleeve (16) fixedly connected to the housing (8), a first piston (17) slidably connected inside the sleeve (16), a spring (18) on one side of the first piston (17), a limit pin (19) fixedly connected to the side wall of the first piston (17), a pin groove (20) opened on the side wall of the limit block (15), one end of the limit pin (19) passes through the sleeve (16) and extends into the pin groove (20); an air inlet (21) is opened on the side wall of the sleeve (16), and an exhaust hole (22) communicating with the upper valve body housing (8) is opened at the bottom; when the pressure inside the housing (8) increases, gas enters the sleeve (16) through the air inlet (21), pushes the first piston (17) to move, and causes the limit pin (19) to disengage from the pin groove (20).

3. The protection device according to claim 2, characterized in that: The adjustment assembly includes a second piston (23), and a stud (24) is threadedly connected to one side of the sleeve (16). One end of the stud (24) passes through the sleeve (16) and is rotatably connected to the second piston (23). By rotating the stud (24), the position of the second piston (23) can be adjusted, thereby changing the compression degree of the spring (18).

4. The protection device according to claim 1, characterized in that: The side wall of the housing (8) is provided with a maintenance control operation port (25), and a sealing door (26) is provided on one side of the maintenance control operation port (25) and is detachably connected to the housing (8).

5. The protection device according to claim 1, characterized in that: A sealing plate (27) is provided on one side of the relief groove (4), and the sealing plate (27) is detachably connected to the cover plate (3).

6. The protection device according to claim 1, characterized in that: The weight of the counterweight (14) is set to be able to press the rack (13) down and drive the toothed ring (12) to rotate.

7. The protection device according to claim 2 or 3, characterized in that: The spring (18) is located between the first piston (17) and the second piston (23).

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