A throw-in check valve

Abstract

The utility model relates to check valve technical field especially relates to a kind of investment type check valve. Investment type check valve includes in position pipe head and valve core assembly, and the inner wall of in position pipe head is equipped with inner clamping groove and sealing cone surface, and valve core assembly includes valve core main body, guide sleeve, elastic locking sleeve and main spring, guide sleeve is fixedly installed in the upper end of valve core main body, elastic locking sleeve is sleeved in the outside of guide sleeve, its lateral wall is equipped with several elastic grooves, its lower end outer wall is equipped with locking boss, upper end outer wall is equipped with fishing boss, its inner wall lower end is equipped with inner cone surface, inner wall upper end is equipped with spring stop shoulder, the bottom end outer wall of guide sleeve is equipped with insertion sleeve, and the top of insertion sleeve is equipped with guide cone surface and lower cylindrical surface, guide cone surface and inner cone surface contact cooperation, and main spring is sleeved on guide sleeve and located in elastic locking sleeve. Investment type check valve provided by the utility model has the advantages of locking reliable, sealing performance stable, and fishing recovery convenient.

Description

Technical Field

[0001] This utility model relates to the field of check valve technology, and in particular to an insertable check valve. Background Technology

[0002] In oil and gas drilling operations, drop-in check valves (also known as drop-in one-way valves or bottom hole check valves) are an important downhole tool. They are usually installed at a predetermined position on the drill string to prevent formation fluids from gushing upwards along the drill string cavity during tripping or connecting single sections, thereby effectively avoiding blowout accidents and ensuring operational safety.

[0003] Existing drop-in check valves typically consist of a positioning head and a valve core assembly, with the valve core assembly held in place by a locking mechanism. However, traditional valve core locking structures are complex, difficult to assemble and disassemble, and prone to locking failure due to vibration or pressure fluctuations during operation. When retrieving the valve core, the docking operation between the retrieval tool and the valve core is cumbersome, with a low success rate, affecting the overall efficiency and safety of the tool.

[0004] Therefore, it is necessary to provide a new type of submersible check valve to solve the above-mentioned technical problems. Utility Model Content

[0005] To solve the above-mentioned technical problems, this utility model provides an insertable check valve.

[0006] The submersible check valve provided by this utility model includes: a positioning tube head and a valve core assembly. The inner wall of the positioning tube head has an inner groove and a sealing cone surface. The valve core assembly includes a valve core body, a guide sleeve, an elastic locking sleeve, and a main spring. The guide sleeve is fixedly installed on the upper end of the valve core body. The elastic locking sleeve has a cylindrical structure and is sleeved on the outside of the guide sleeve. Its side wall has several elastic grooves, and its lower outer wall has a locking boss for engaging with the inner groove. Its upper outer wall has a locking boss for engaging with the inner groove. The wall is provided with a retrieval protrusion, and its lower inner wall is provided with an inner conical surface, and its upper inner wall is provided with a spring shoulder. The bottom outer wall of the guide sleeve is fixedly installed with a plug sleeve. The top of the plug sleeve is provided with a guide conical surface and a lower cylindrical surface. The guide conical surface is in contact with the inner conical surface. The main spring is sleeved on the guide sleeve and located inside the elastic locking sleeve. The top of the main spring is fixedly connected to the spring shoulder, and the bottom of the main spring is fixedly connected to the end face of the lower cylindrical surface. The top of the guide sleeve is threaded with a pressure cap.

[0007] Preferably, the elastic locking sleeve is made of spring steel, and several elastic grooves are arranged along the axial direction of the elastic locking sleeve to give it radial elasticity.

[0008] Preferably, the insertion sleeve has a limiting groove on the side wall between the guide cone surface and the lower cylindrical surface, and the bottom of the locking boss has a slope with the same inclination as the inner cone surface.

[0009] Preferably, the protrusion height of the salvage boss is greater than the protrusion height of the locking boss.

[0010] Preferably, the inner cavity of the valve core body is provided with a steel ball seat, and a spring seat is installed at the bottom of the inner cavity of the valve core body. A guide hole is opened in the middle of the spring seat, and a guide rod is slidably installed in the guide hole. A steel ball that contacts and seals with the steel ball seat is fixedly installed at the top of the guide rod. A compression spring is sleeved on the guide rod. One end of the compression spring is fixedly connected to the bottom of the steel ball, and the other end of the compression spring is fixedly connected to the spring seat. Multiple guide holes are opened on the spring seat.

[0011] Preferably, a rubber sleeve and a sealing ring that contact and seal with the sealing cone surface are installed on the outer wall of the valve core body.

[0012] Preferably, the upper end of the positioning tube head is provided with an internal thread for connecting with the upper drill string; the lower end is provided with an external thread for connecting with the lower drill string.

[0013] Preferably, it also includes a retrieval tool that can be inserted into the positioning tube head from top to bottom. The retrieval tool includes a boom that is inserted into the top of the guide sleeve, and a retrieval sleeve is fixedly installed on the outer side wall of the boom. The bottom of the retrieval sleeve has an inner chamfer, and the inner side wall of the bottom end of the retrieval sleeve has an annular groove that engages with the retrieval boss. The upper surface of the retrieval boss has an outer chamfer that matches the inner chamfer.

[0014] Compared with related technologies, the submersible check valve provided by this utility model has the following advantages: 1. This utility model provides an elastic locking sleeve with an elastic groove, and an inner conical surface inside the sleeve that slides in cooperation with the guide conical surface on the guide sleeve. When the valve core assembly is inserted into the positioning tube head, the elastic locking sleeve is pushed away from the insertion sleeve by the elastic force of the main spring, so that the locking boss is firmly inserted into the inner groove of the positioning tube head, thus achieving self-locking. 2. This utility model features a retrieval protrusion on the upper end of the elastic locking sleeve, along with a specially designed retrieval tool. When the retrieval tool is lowered, the inner chamfer of the retrieval sleeve guides the outer chamfer of the retrieval protrusion, easily guiding the retrieval sleeve to enclose the retrieval protrusion and insert it into the annular groove. During the downward pressing process, the locking protrusion can be pressed into the limiting groove, preventing the locking protrusion from contacting the inner groove and affecting the retrieval. This enables rapid docking and retrieval, is easy to operate, and has a high success rate. Attached Figure Description

[0015] Figure 1A schematic diagram of a preferred embodiment of the submersible check valve provided by this utility model; Figure 2 A half-sectional view of the submersible check valve provided by this utility model. Figure 3 This is a schematic diagram of the structure of the elastic locking sleeve provided by this utility model; Figure 4 A schematic diagram of the structure of the valve core body provided by this utility model with a guide sleeve installed; Figure 5 A schematic diagram of the structure of the recycling tool provided by this utility model.

[0016] The diagram labels are as follows: 1. Positioning pipe head; 11. Inner groove; 12. Sealing cone surface; 13. Internal thread; 14. External thread; 2. Valve core assembly; 21. Valve core body; 211. Rubber sleeve; 212. Sealing ring; 22. Guide sleeve; 221. Insert sleeve; 2211. Guide cone surface; 2212. Lower cylindrical surface; 2213. Limiting groove; 222. Pressure cap; 23. Elastic locking sleeve; 231. Elastic groove; 232. Locking boss; 233. Retrieval boss; 234. Inner cone surface; 235. Spring shoulder; 24. Main spring; 25. Steel ball seat; 26. Spring seat; 201. Guide hole; 27. Guide rod; 28. Steel ball; 29. ​​Compression spring; 3. Recovery tool; 31. Lifting rod; 32. Recovery sleeve; 33. Inner chamfer; 301. Annular groove. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0018] The specific implementation of this utility model will be described in detail below with reference to specific embodiments.

[0019] Please see Figures 1 to 5 The present invention provides an insertable check valve, which includes a positioning tube head 1 and a valve core assembly 2. The inner wall of the positioning tube head 1 is provided with an inner groove 11 and a sealing cone surface 12. The valve core assembly 2 includes a valve core body 21, a guide sleeve 22, an elastic locking sleeve 23 and a main spring 24.

[0020] The positioning tube head 1 has an internal thread 13 at its upper end for connecting with the upper drill string; and an external thread 14 at its lower end for connecting with the lower drill string. In this way, the positioning tube head 1 can be conveniently connected in series to a predetermined position in the drill string.

[0021] Please see Figure 1 , Figure 2 , Figure 3 and Figure 4 The guide sleeve 22 is fixedly installed on the upper end of the valve core body 21. The two can be fixedly connected by threads or welding. The elastic locking sleeve 23 is a cylindrical structure and is sleeved on the outside of the guide sleeve 22. The side wall of the elastic locking sleeve 23 has several elastic grooves 231, which makes the elastic locking sleeve 23 have the ability to contract and expand radially. The lower outer wall of the elastic locking sleeve 23 has a locking boss 232 for engaging with the inner groove 11, and the upper outer wall has a retrieval boss 233. The lower end of the inner wall of the elastic locking sleeve 23 has an inner conical surface 234, and the upper end of the inner wall has a spring shoulder 235.

[0022] Please see Figure 1 , Figure 3 and Figure 4 A plug sleeve 221 is fixedly installed on the outer wall of the bottom end of the guide sleeve 22. The top end of the plug sleeve 221 is provided with a guide cone surface 2211 and a lower cylindrical surface 2212. The guide cone surface 2211 and the inner cone surface 234 are in contact and fit together. The two are inclined surfaces with the same slope and can slide relative to each other. The main spring 24 is sleeved on the guide sleeve 22 and located inside the elastic locking sleeve 23. The top end of the main spring 24 is fixedly connected to the spring shoulder 235. The bottom end of the main spring 24 is fixedly connected to the end face of the lower cylindrical surface 2212. A pressure cap 222 is threaded on the top end of the guide sleeve 22 to restrict the elastic locking sleeve 23 from coming off upward.

[0023] It should be noted that when valve core assembly 2 is in its initial free state (e.g.) Figure 1 As shown), under the elastic force of the main spring 24, the elastic locking sleeve 23 is pushed upward, causing the inner conical surface 234 to slide relative to the guide conical surface 2211. Since the inner conical surface 234 is a conical hole with a larger upper part and a smaller lower part, and the guide conical surface 2211 is a cone with a smaller upper part and a larger lower part, when the two slide relative to each other, the lower end of the elastic locking sleeve 23 expands radially under the expansion of the guide conical surface 2211, causing the locking boss 232 to protrude outward. When the valve core assembly 2 is inserted from the upper end of the positioning tube head 1, the valve core assembly 2 moves downward as a whole, and the outer slope of the locking boss 232 contacts the inner wall of the positioning tube head 1, forcing the lower end of the elastic locking sleeve 23 to contract radially until the locking boss 232 moves down to the position of the inner groove 11. At this time, under the continuous elastic force of the main spring 24, the guide cone surface 2211 moves away from the inner cone surface 234, realizing automatic locking.

[0024] Furthermore, the elastic locking sleeve 23 is made of spring steel, which has excellent elasticity and fatigue resistance. Several elastic grooves 231 are arranged along the axial direction of the elastic locking sleeve 23, so that the side wall of the elastic locking sleeve 23 is divided into multiple elastic flap structures, thereby giving it radial elasticity and facilitating radial deformation during locking and releasing.

[0025] In an embodiment of this utility model, the insert sleeve 221 has a limiting groove 2213 on the side wall between the guide cone surface 2211 and the lower cylindrical surface 2212. The bottom of the locking boss 232 has a slope with the same inclination as the inner cone surface 234. During retraction, by pressing down on the elastic locking sleeve 23, after the inner cone surface 234 slides down away from the guide cone surface 2211, the bottom slope of the locking boss 232 continues to press and cooperate with the guide cone surface 2211, so that the elastic locking sleeve 23 continues to contract until the locking boss 232 contracts and slides to the limiting groove 2213. Thus, during retraction, the rebound of the locking boss 232 is restricted, preventing it from contacting and cooperating with the inner groove 11, which would affect the retraction.

[0026] The protrusion height of the retrieval boss 233 is greater than that of the locking boss 232. This design makes it easier for the retrieval tool 3 to accurately fit over the retrieval boss 233 from above, avoiding interference with the locking boss 232 below, and improving the success rate and convenience of the retrieval operation.

[0027] In the embodiments of this utility model, please refer to Figure 1 and Figure 2 The inner cavity of the valve core body 21 is provided with a steel ball seat 25, and a spring seat 26 is installed at the bottom of the inner cavity of the valve core body 21. A guide hole is opened in the middle of the spring seat 26, and a guide rod 27 is slidably installed in the guide hole. A steel ball 28 that contacts and seals with the steel ball seat 25 is fixedly installed at the top of the guide rod 27. A compression spring 29 is sleeved on the guide rod 27. One end of the compression spring 29 is fixedly connected to the bottom of the steel ball 28, and the other end of the compression spring 29 is fixedly connected to the spring seat 26. Multiple guide holes 201 are opened on the spring seat 26.

[0028] It should be noted that under normal operating conditions (drilling fluid positive circulation), the drilling fluid enters the inner cavity of the valve core body 21 from above, overcoming the elastic force of the compression spring 29 and pushing the steel ball 28 downward, causing the steel ball 28 to disengage from the steel ball seat 25. The drilling fluid flows downward along the gap between the steel ball seat 25 and the steel ball 28, the gap between the guide rod 27 and the spring seat 26, and the guide hole 201, achieving normal circulation. When circulation stops or a well kick occurs, the fluid pressure below increases, pushing the steel ball 28 upward to reset and tightly fit against the steel ball seat 25, achieving one-way shut-off and preventing fluid from flowing upward.

[0029] Furthermore, a rubber sleeve 211 and a sealing ring 212 are installed on the outer wall of the valve core body 21 to seal against the sealing cone surface 12. The rubber sleeve 211 is made of elastic rubber material, and the sealing ring 212 is an O-ring. When the valve core assembly 2 is locked in place, the rubber sleeve 211 and the sealing ring 212 are tightly fitted with the sealing cone surface 12 at the same time, forming a double sealing barrier, which further improves the reliability of the seal.

[0030] In the embodiments of this utility model, please refer to Figures 1 to 5 The drop-in check valve provided by this utility model also includes a retrieval tool 3 that can be inserted into the positioning pipe head 1 from top to bottom. The retrieval tool 3 includes a lifting rod 31, which is inserted into the top of the guide sleeve 22. A retrieval sleeve 32 is fixedly installed on the outer side wall of the lifting rod 31. An inner chamfer 33 is provided at the bottom of the retrieval sleeve 32. An annular groove 301 that engages with the retrieval boss 233 is provided on the inner side wall of the bottom end of the retrieval sleeve 32. An outer chamfer that matches the inner chamfer 33 is provided on the upper surface of the retrieval boss 233.

[0031] It should be noted that during use, when the valve core assembly 2 needs to be retrieved, the retrieval tool 3 is connected to the lower end of the retrieval rope or drill rod and lowered from above the positioning pipe head 1. The inner chamfer 33 at the bottom of the retrieval sleeve 32 first contacts the outer chamfer on the upper surface of the retrieval boss 233. After contact, the elastic locking sleeve 23 is pressed downward. During the downward movement of the elastic locking sleeve 23, the inner conical surface 234 contacts the guide conical surface 2211. Under the contact compression, the elastic locking sleeve 23 contracts inward. Continue pressing until the locking boss 232 exits the inner groove 1. 1. Disengage from the device and slide into the limiting slot 2213 to release the locking boss 232 from the inner slot 11. Then, continue to press down the recovery tool 3 so that the retrieval boss 233 is engaged in the annular groove 301. At this time, lift the recovery tool 3, and the entire valve core assembly 2 can be lifted upward through the engagement of the annular groove 301 and the retrieval boss 233. During the lifting process, the elastic locking sleeve 23 is subjected to an upward pulling force, which pulls the insertion sleeve 221 and drives the guide sleeve 22 to slide upward, thereby successfully removing the valve core assembly 2 from the positioning tube head 1.

[0032] The working principle of the submersible check valve provided by this utility model is as follows: In use, first connect the positioning tube head 1 to the upper drill string and the lower drill string respectively through the upper internal thread 13 and the lower external thread 14, so that it is connected in series to the predetermined position in the drill string. The valve core assembly 2 is inserted from the upper end of the positioning tube head 1. The valve core assembly 2 descends as a whole. When the outer slope of the locking boss 232 at the lower end of the elastic locking sleeve 23 contacts the inner wall of the positioning tube head 1, it forces the lower end of the elastic locking sleeve 23 to contract radially, allowing the valve core assembly 2 to continue descending. When the locking boss 232 descends to the position of the inner groove 11 on the inner wall of the positioning tube head 1, under the continuous elastic force of the main spring 24, the elastic locking sleeve 23 is pushed upward, causing the inner cone surface 234 to move away from the guide cone surface 2211, so that the locking boss 232 is stably locked in the inner groove 11, achieving automatic locking. At this time, the rubber sleeve 211 and the sealing ring 21 on the outer wall of the valve core body 21... 2. It fits tightly against the sealing cone surface 12 of the positioning pipe head 1 to form a double seal. After being put into operation, during normal circulation, the drilling fluid enters the inner cavity of the valve core body 21 from above. The pressure of the drilling fluid overcomes the elastic force of the compression spring 29 and pushes the steel ball 28 downward, causing the steel ball 28 to disengage from the steel ball seat 25. The drilling fluid flows downward along the gap between the steel ball seat 25 and the steel ball 28, the gap between the guide rod 27 and the spring seat 26, and the guide hole 201 to achieve normal circulation. When circulation stops or a well kick occurs, the fluid pressure below increases, pushing the steel ball 28 to reset upward and fit tightly against the steel ball seat 25 to achieve one-way cutoff, effectively preventing the formation fluid from gushing upward along the inner cavity of the drill string. When the valve core assembly 2 needs to be retrieved, the retrieval tool 3 is connected to the lower end of the retrieval rope or drill rod and lowered from above the positioning pipe head 1. The inner chamfer 33 at the bottom of the retrieval sleeve 32 first contacts the outer chamfer on the upper surface of the retrieval boss 233. After contact, the elastic locking sleeve 23 is pressed down. During the downward movement of the elastic locking sleeve 23, the inner conical surface 234 contacts the guide conical surface 2211. Under the contact compression, the elastic locking sleeve 23 contracts inward. Continue pressing until the locking boss 232 disengages from the inner groove 11 and slides into the limiting groove 2213, releasing the locking boss 232 from the inner groove 11. Then, continue pressing down the retrieval tool 3, and the retrieval boss 233 is engaged in the annular groove 301. At this time, the retrieval tool 3 is lifted up, and the entire valve core assembly 2 can be pulled up and taken out through the engagement of the annular groove 301 and the retrieval boss 233.

[0033] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the content of this utility model specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. An insertable check valve, comprising: The positioning tube head (1) and valve core assembly (2) are characterized in that the inner wall of the positioning tube head (1) is provided with an inner groove (11) and a sealing cone surface (12), and the valve core assembly (2) includes a valve core body (21), a guide sleeve (22), an elastic locking sleeve (23) and a main spring (24). The guide sleeve (22) is fixedly installed on the upper end of the valve core body (21). The elastic locking sleeve (23) is a cylindrical structure and is sleeved on the outside of the guide sleeve (22). Its side wall is provided with a plurality of elastic grooves (231). Its lower outer wall is provided with a locking boss (232) for engaging with the inner groove (11), and its upper outer wall is provided with a retrieval boss (233). The lower end of its inner wall is provided with a locking boss (232) for engaging with the inner groove (11). The guide sleeve (22) has an inner conical surface (234) with a spring shoulder (235) on the upper end of its inner wall. A plug sleeve (221) is fixedly installed on the outer wall of the bottom end of the guide sleeve (22). The top end of the plug sleeve (221) has a guide conical surface (2211) and a lower cylindrical surface (2212). The guide conical surface (2211) is in contact with the inner conical surface (234). The main spring (24) is sleeved on the guide sleeve (22) and located inside the elastic locking sleeve (23). The top end of the main spring (24) is fixedly connected to the spring shoulder (235), and the bottom end of the main spring (24) is fixedly connected to the end face of the lower cylindrical surface (2212). A pressure cap (222) is threaded onto the top end of the guide sleeve (22).

2. The submersible check valve according to claim 1, characterized in that, The elastic locking sleeve (23) is made of spring steel, and several elastic grooves (231) are arranged along the axial direction of the elastic locking sleeve (23) to give it radial elasticity.

3. The submersible check valve according to claim 1, characterized in that, The insertion sleeve (221) has a limit slot (2213) on the side wall between the guide cone surface (2211) and the lower cylindrical surface (2212), and the bottom of the locking boss (232) has a slope with the same inclination as the inner cone surface (234).

4. The submersible check valve according to claim 1, characterized in that, The protrusion height of the salvage boss (233) is greater than that of the locking boss (232).

5. The submersible check valve according to claim 1, characterized in that, The inner cavity of the valve core body (21) is provided with a steel ball seat (25), and a spring seat (26) is installed at the bottom of the inner cavity of the valve core body (21). A guide hole is opened in the middle of the spring seat (26), and a guide rod (27) is slidably installed in the guide hole. A steel ball (28) is fixedly installed at the top of the guide rod (27) and is in contact with and sealed to the steel ball seat (25). A compression spring (29) is sleeved on the guide rod (27). One end of the compression spring (29) is fixedly connected to the bottom of the steel ball (28), and the other end of the compression spring (29) is fixedly connected to the spring seat (26). A plurality of guide holes (201) are opened on the spring seat (26).

6. The submersible check valve according to claim 1, characterized in that, The valve core body (21) is equipped with a rubber sleeve (211) and a sealing ring (212) that are in contact with and seal the sealing cone surface (12).

7. The submersible check valve according to claim 1, characterized in that, The upper end of the positioning tube head (1) is provided with an internal thread (13) for connecting with the upper drill string; the lower end is provided with an external thread (14) for connecting with the lower drill string.

8. The submersible check valve according to claim 1, characterized in that, It also includes a retrieval tool (3) that can be inserted into the positioning tube head (1) from top to bottom. The retrieval tool (3) includes a lifting rod (31), which is inserted into the top of the guide sleeve (22). A retrieval sleeve (32) is fixedly installed on the outer side wall of the lifting rod (31). The bottom of the retrieval sleeve (32) is provided with an inner chamfer (33). The inner side wall of the bottom end of the retrieval sleeve (32) is provided with an annular groove (301) that engages with the retrieval boss (233). The upper surface of the retrieval boss (233) is provided with an outer chamfer that matches the inner chamfer (33).

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