A hydraulic reciprocating tractor

Abstract

A hydraulic reciprocating tractor relates to the technical field of oil and gas field development. An upper piston is provided in the middle of the upper cylinder barrel, and the lower part of the upper piston is fixedly connected to a telescopic tube. A liquid hole B is provided on the top of the telescopic tube. The lower part of the upper cylinder barrel is connected to the cylinder head through a threaded seal. The telescopic tube is connected to the inner hole of the cylinder head through a sealing ring. After the telescopic tube extends out of the cylinder head, it is connected to an anchoring mechanism. The beneficial effect of the present invention is that by setting the inner valve core and the outer valve core to cooperate with each other, when high-pressure liquid is introduced, the upper piston and the telescopic tube are extended, the anchor claws are opened and anchored on the inner wall of the casing, and then the telescopic tube retracts to drive the continuous oil pipe forward, and the continuous reciprocating extension and anchoring are performed until the continuous oil pipe is pulled to the bottom of the well. After reaching the construction position, the high-pressure fluid can be used to perform sand flushing and well washing around the construction position through the overflow hole on the upper cylinder barrel. It has the characteristics of simple structure, large traction force and reliable operation.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas field development, in particular to a hydraulic reciprocating tractor. Background Art

[0002] When using coiled tubing, it needs to be run to the tail end of the horizontal well section. Because horizontal wells often have long horizontal sections or curved wellbore trajectories, the front end of the coiled tubing can get stuck on the inner wall of the casing, making it difficult to descend and unable to reach the intended operation position. This seriously restricts the progress of on-site coiled tubing construction and increases downtime costs.

[0003] A one-way hydraulic reciprocating tractor is an underground tool that can provide traction for the continuous oil tubing body underground, and can be pulled to the construction site for sand flushing and well washing. Currently, existing domestic technologies generally have problems such as poor reliability, large friction, difficulty in lowering, high construction cost, and insufficient traction, which restricts its promotion and application in horizontal well construction operations; in addition, the existing hydraulically driven crawlers at home and abroad have relatively simple functions and can only serve to increase the transportation distance of the continuous oil tubing at the bottom of the well. Therefore, there is an urgent need to develop a hydraulic tractor that can solve the problem of continuous oil tubing transportation in long sections of horizontal wells and can effectively deal with obstruction points. Summary of the Invention

[0004] In order to solve the current problem of continuous tubing getting stuck when running into horizontal wells, having difficulty in descending and being unable to reach the predetermined operating position, we have developed a hydraulic reciprocating tractor.

[0005] The technical solution provided by the present invention is: a hydraulic reciprocating tractor, comprising an upper cylinder, an upper piston provided in the middle of the upper cylinder, a telescopic tube fixedly connected to the lower portion of the upper piston, a fluid hole B being provided at the top of the telescopic tube, the lower portion of the upper cylinder being connected to a cylinder head via a threaded seal, the telescopic tube being connected to the inner hole of the cylinder head via a sealing ring, and the telescopic tube being connected to an anchoring mechanism after extending out of the cylinder head;

[0006] The inner hole of the upper piston is sealed and connected to the lead tube, which extends downward for a distance. The lower part of the lead tube is connected to the limit rod through the long hole D. The inner hole of the telescopic tube is larger than the inner hole of the upper piston. There is a step surface between the inner hole of the telescopic tube and the inner hole of the upper piston. The length of the limit rod is greater than the inner hole diameter of the upper piston. The upper part of the lead tube is threadedly connected to the adapter sleeve, and the adapter sleeve is fixedly connected to the adapter cap and the upper cylinder barrel.

[0007] The upper part of the upper cylinder is provided with an outer valve hole and an inner valve hole, the inner clearance of the outer valve hole is connected to the outer valve core, the inner clearance of the outer valve core is connected to the inner valve core, the inner valve core is connected to the inner valve hole clearance, the upper part of the inner valve hole is a closed structure, and the lower part of the inner valve hole extends to the adapter cap. The upper cylinder is provided with a liquid inlet channel on the left side of the outer valve hole, and an upper drain channel and a lower drain channel are provided on the right side of the outer valve hole. The upper cylinder has an upper drain hole and a lower drain hole on the right side of the outer valve hole, and the upper drain channel is connected to the The upper drain hole is connected, the lower drain channel is connected to the lower drain hole, an upper bypass pipe and a lower bypass pipe are provided on the upper cylinder, the upper portion of the upper bypass pipe is connected to the upper cylinder above the inner valve hole, and the lower portion is connected to the outer valve hole at the lower portion of the upper drain hole, the upper portion of the lower bypass pipe is connected to the outer valve hole at the upper portion of the lower drain hole, and the lower portion is connected to the upper cylinder above the upper piston, the top of the outer valve hole is provided with upper conversion channels on the left and right sides, and the adapter cap is provided with lower conversion channels on the left and right sides of the bottom of the outer valve hole;

[0008] A ring groove is opened in the middle of the outer valve core, and slits evenly distributed around the circumference are opened on the upper side of the ring groove.

[0009] The inner valve core has elongated holes C on both sides of its center. An upper liquid inlet groove is located on the left side of the upper portion of the inner valve core, and an upper liquid outlet groove is located on the right side. A lower liquid inlet groove is located on the left side of the lower portion of the inner valve core, and a lower liquid outlet groove is located on the right side of the lower portion of the inner valve core. A liquid outlet hole A is located at the bottom of the inner valve core, and two elongated holes B are located on the top of the inner valve core, oriented in the left and right directions. An anti-rotation rod is inserted into the elongated hole B of the inner valve core. Two countersunk holes are located on the top of the inner valve hole, and the anti-rotation rod is inserted into these two countersunk holes.

[0010] The limit rod is fixedly connected to the lead rod, the top of the lead rod is fixedly connected to the bottom of the inner valve core, the middle of the lead rod is fixedly connected to the limit bolt, a limit coupling is sleeved on the middle of the lead tube, the limit coupling is located on the upper part of the upper piston, and the limit bolt passes through the long hole A on the lead tube and is fixedly connected to the limit coupling;

[0011] The anchoring mechanism includes a lower cylinder, the top of the lower cylinder is threaded and sealed to connect the telescopic tube, a lower piston is provided in the lower cylinder, the lower piston is connected to the lower cylinder through the clearance fit of the sealing ring, the lower part of the lower piston is fixedly connected to the telescopic column with a smaller diameter, the bottom of the lower cylinder is provided with anchor claws evenly distributed around the circumference, the lower cylinder is hinged to the upper part of the anchor claw, the telescopic column is hinged to the connecting rod after extending out of the lower cylinder, the other side of the connecting rod is hinged to the lower part of the anchor claw, and a compression spring is provided between the lower piston and the bottom of the lower cylinder.

[0012] An upper joint is processed on the top of the upper cylinder, and the upper cylinder is connected to the plugging sleeve through a pin at the lower part of the upper joint. A ball seat hole is processed in the inner hole of the plugging sleeve. An overflow hole connected to the outside is opened at the position of the plugging sleeve on the upper cylinder, and the plugging sleeve covers the overflow hole.

[0013] The beneficial effects of the present invention are as follows: by arranging the inner valve core and the outer valve core to cooperate with each other, when high-pressure liquid is introduced, after the upper piston and the telescopic tube are extended, the anchor claws are opened and anchored on the inner wall of the casing, and then the telescopic tube retracts to drive the continuous oil tubing forward, and the extension and anchoring are repeated continuously until the continuous oil tubing is pulled to the bottom of the well. After reaching the construction position, a plugging ball is pumped in through the continuous oil tubing, and the plugging ball falls on the ball seat hole of the plugging sleeve for sealing, and the shear pin is continuously injected at high pressure. At this time, the plugging sleeve descends to the lower annular cavity of the sealing tool, and the high-pressure fluid can be used for sand flushing and well washing around the construction position through the overflow hole on the upper cylinder. The present invention has the characteristics of simple structure, large traction force and reliable operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Attachment Figure 1 It is a structural schematic diagram of the present invention;

[0015] Attachment Figure 2 It is attached Figure 1 A magnified view of point A;

[0016] Attachment Figure 3 It is attached Figure 1 Working drawings;

[0017] Attachment Figure 4 It is a structural schematic diagram of the upper cylinder in the present invention;

[0018] Attachment Figure 5 It is a structural diagram of the outer valve core of the present invention;

[0019] Attachment Figure 6 It is a structural schematic diagram of the inner valve core in the present invention;

[0020] Attachment Figure 7 It is attached Figure 1 Another working diagram of;

[0021] Attachment Figure 8 This is the attached Figure 3 This is an enlarged view of point B;

[0022] Attachment Figure 9 It is attached Figure 7 Enlarged view of point C;

[0023] Attachment Figure 10 It is a structural schematic diagram of the anchoring mechanism in the present invention.

[0024] In the figure, 1-upper cylinder, 2-upper joint, 3-blocking sleeve, 4-pin, 5-overflow hole, 6-upper piston, 7-telescopic tube, 8-cylinder cover, 9-anchoring mechanism, 10-sleeve, 11-lead tube, 12-lead rod, 13-limit rod, 14-step surface, 15-adapter sleeve, 16-inner valve core, 17-outer valve core, 18-anti-rotation rod, 19-limit coupling, 20-limit bolt, 21-long hole A, 22-long hole B, 23-adapter cap, 24-liquid inlet channel, 25-lower bypass pipe, 26-upper bypass pipe, 27-upper drainage hole, 28-lower drainage hole, 29-lower drainage channel, 30-upper drainage channel, 31-upper conversion channel, 32-lower conversion channel, 33-external valve hole, 34-inner valve hole, 35-ring groove, 36-slit, 37-long hole C, 38-upper liquid inlet groove, 39-sink hole, 40-upper drainage groove, 41-lower drainage groove, 42-liquid hole A, 43-lower liquid inlet groove, 44-lower piston, 45-lower cylinder, 46-anchor claw, 47-connecting rod, 48-telescopic column, 49-liquid hole B, 50-long hole D. DETAILED DESCRIPTION

[0025] like Figures 1 to 10 As shown, a hydraulic reciprocating tractor includes an upper cylinder 1, an upper piston 6 is provided in the middle of the upper cylinder 1, the lower portion of the upper piston 6 is fixedly connected to a telescopic tube 7, a liquid hole B49 is formed at the top of the telescopic tube 7, the lower portion of the upper cylinder 1 is connected to a cylinder head 8 through a threaded seal, the telescopic tube 7 is connected to the inner hole of the cylinder head 8 through a sealing ring, and the telescopic tube 7 is connected to an anchoring mechanism 9 after extending out of the cylinder head 8;

[0026] The inner hole of the upper piston 6 is sealed and connected to the lead tube 11. The lead tube 11 extends downward for a distance. The lower part of the lead tube 11 is connected to the limit rod 13 through the long hole D50. The inner hole of the telescopic tube 7 is larger than the inner hole of the upper piston 6. There is a step surface 14 between the inner hole of the telescopic tube 7 and the inner hole of the upper piston 6. The length of the limit rod 13 is greater than the inner hole diameter of the upper piston 6. The upper part of the lead tube 11 is threadedly connected to the adapter sleeve 15. The adapter sleeve 15 is fixedly connected to the adapter cap 23 and the upper cylinder 1;

[0027] The upper part of the upper cylinder 1 is provided with an outer valve hole 33 and an inner valve hole 34. The inner clearance of the outer valve hole 33 is connected to the outer valve core 17. The inner clearance of the outer valve core 17 is connected to the inner valve core 16. The inner valve core 16 is connected to the inner valve hole 34 with a clearance fit. The upper part of the inner valve hole 34 is a closed structure. The lower part of the inner valve hole 34 extends to the adapter cap 23. The upper cylinder 1 is provided with a liquid inlet channel 24 on the left side of the outer valve hole 33. The upper cylinder 1 is provided with an upper drain channel 30 and a lower drain channel 29 on the right side of the outer valve hole 33. The upper cylinder 1 is opened on the right side of the outer valve hole 33 with an upper drain hole 27 and a lower drain hole 28. The upper drain channel 30 is connected to the upper drain hole 27, and the lower drain channel 29 is connected to the lower drain hole 28. The upper cylinder 1 is provided with an upper bypass pipe 26 and a lower bypass pipe 25. The upper portion of the upper bypass pipe 26 is connected to the upper cylinder 1 above the inner valve hole 34, and the lower portion is connected to the outer valve hole 33 at the lower position of the upper drain hole 27. The upper portion of the lower bypass pipe 25 is connected to the outer valve hole 33 at the upper position of the lower drain hole 28, and the lower portion is connected to the upper cylinder 1 above the upper piston 6. The top of the outer valve hole 33 is provided with upper conversion channels 31 on the left and right sides, and the adapter cap 23 is provided with lower conversion channels 32 on the left and right sides of the bottom of the outer valve hole 33.

[0028] An annular groove 35 is formed in the middle of the outer valve core 17, and slits 36 are formed on the upper side of the annular groove 35 and are evenly distributed around the circumference of the outer valve core 17;

[0029] The inner valve core 16 has two elongated holes C37 on its left and right sides. An upper liquid inlet groove 38 and an upper liquid outlet groove 40 are defined on the left and right sides of the upper portion of the inner valve core 16. A lower liquid inlet groove 43 and a lower liquid outlet groove 41 are defined on the right side of the lower portion of the inner valve core 16. A liquid outlet hole A42 is defined at the bottom of the inner valve core 16. Two elongated holes B22 are defined in the top of the inner valve core 16, each extending in a left and right direction. The anti-rotation rod 18 is inserted into the elongated hole B22 of the inner valve core 16. Two countersunk holes 39 are defined at the top of the inner valve hole 34, into which the anti-rotation rod 18 is inserted.

[0030] The limit rod 13 is fixedly connected to the lead rod 12, the top of the lead rod 12 is fixedly connected to the bottom of the inner valve core 16, the middle of the lead rod 12 is fixedly connected to the limit bolt 20, and a limit coupling 19 is sleeved on the middle of the lead tube 11. The limit coupling 19 is located on the upper part of the upper piston 6. The limit bolt 20 passes through the long hole A21 on the lead tube 11 and is fixedly connected to the limit coupling 19;

[0031] The anchoring mechanism 9 includes a lower cylinder 45, the top of the lower cylinder 45 is threaded and sealed to the telescopic tube 7, a lower piston 44 is provided in the lower cylinder 45, the lower piston 44 is connected to the lower cylinder 45 through a sealing ring clearance fit, the lower part of the lower piston 44 is fixedly connected to a telescopic column 48 with a smaller diameter, and the bottom of the lower cylinder 45 is provided with an anchor claw 46 evenly distributed around the circumference, the lower cylinder 45 is hinged to the upper part of the anchor claw 46, and the telescopic column 48 extends out of the lower cylinder 45 and is hinged to the connecting rod 47, the other side of the connecting rod 47 is hinged to the lower part of the anchor claw 46, and a compression spring is provided between the lower piston 44 and the bottom of the lower cylinder 45.

[0032] An upper joint 2 is processed on the top of the upper cylinder 1, and the upper cylinder 1 is connected to the blocking sleeve 3 at the lower part of the upper joint 2 through a pin 4. A ball seat hole is processed in the inner hole of the blocking sleeve 3. An overflow hole 5 connected to the outside is opened at the position of the blocking sleeve 3 in the upper cylinder 1, and the blocking sleeve 3 covers the overflow hole 5.

[0033] When in use, connect the upper connector 2 of the tractor to the front end of the coiled tubing, and lower the coiled tubing into the well. When the tubing is stuck, introduce high-pressure liquid into the coiled tubing to unblock and pull it. When the upper piston 6 is at the lowest position, the step surface 14 pushes the limit rod 13 downward to the bottom of the long hole D50 of the guide tube 11, and the guide rod 12 pulls the inner valve core 16 down. At this time, the upper liquid inlet groove 38 of the inner valve core 16 makes the liquid inlet channel 24 and the upper conversion channel 31 on the left communicate. The upper conversion channel 31 on the left is connected to the top of the outer valve core 17. When the liquid pressure pushes the outer valve core 17 down, the long hole C37 of the inner valve core 16 is connected to the slit 36 ​​and the upper bypass pipe 26 of the outer valve core 17, and the annular groove 38 of the outer valve core 17 is connected. 5 connects the lower bypass pipe 25 and the lower drain hole 28. High-pressure liquid flows from the top of the upper cylinder 1 to the slit 36 ​​of the outer valve core 17, the long hole C37 of the inner valve core 16, and the liquid hole A42 to the upper part of the lower piston 44, pushing the lower piston 44 downward. The downward movement of the lower piston 44 causes the anchor claws 46 to open and anchor on the casing 10. The anchoring force can be adjusted according to the liquid pressure as needed. The higher the liquid pressure, the greater the anchoring force of the anchor claws 46. At the same time, the high-pressure liquid flows through the liquid hole B49 to the lower end of the upper piston 6. The liquid pressure pushes the upper piston 6 upward, driving the telescopic tube 7 upward. The integral tractor drives the coiled tubing downward. The liquid on the upper part of the upper piston 6 flows out through the lower bypass pipe 25 and the lower drain hole 28 into the casing 10.

[0034] When the upper piston 6 is pushed to the uppermost position, the upper piston 6 lifts the limit coupling 19 and the limit bolt 20 moves upward to the top of the long hole A21, and the limit bolt 20 drives the lead rod 12 to push the inner valve core 16 upward. At this time, the upper drainage groove 40 on the right side of the inner valve core 16 makes the upper conversion channel 31 on the right side communicate with the upper drainage channel 30, and the liquid inlet channel 24 is connected to the lower conversion channel 32 on the left side. The lower conversion channel 32 on the left is connected to the bottom of the outer valve core 17. The liquid pressure pushes the outer valve core 17 upward, and the annular groove 35 of the outer valve core 17 makes the upper bypass pipe 26 and the lower bypass pipe 25 communicate. The lower part of the upper conversion channel 31 on the right is connected to the The top of the outer valve core 17 is connected, the long hole C37 of the inner valve core 16 is connected to the slit 36 ​​of the outer valve core 17, the slit 36 ​​is connected to the upper drain hole 27, and the liquid in the upper part of the lower piston 44 flows from the guide tube 11 through the liquid hole A42, the long hole C37, the slit 36 ​​and the upper drain hole 27 to the casing 10. The lower piston 44 rises under the action of the compression spring, and the anchor claw 46 contracts to release the anchor. The high-pressure liquid flows from the upper bypass pipe 26 and the lower bypass pipe 25 to the upper part of the upper piston 6, pushing the upper piston 6 and the telescopic tube 7 downward. When they descend to the bottom position, they are re-anchored. The contraction of the telescopic tube 7 drives the entire tractor and the coiled tubing forward.

[0035] By setting the inner valve core 16 and the outer valve core 17 to cooperate with each other, when high-pressure liquid is introduced, the upper piston 6 and the telescopic tube 7 are extended, and the anchor claws 46 are opened and anchored on the inner wall of the casing 10. Then the telescopic tube 7 retracts to drive the coiled tubing forward, and the telescopic and anchoring are repeated continuously until the coiled tubing is pulled to the bottom of the well. After reaching the construction position, the plugging ball is pumped in through the coiled tubing, and the plugging ball falls on the ball seat hole of the plugging sleeve 3 for sealing. Continuous high pressure is injected to shorten the 3 pins 4. At this time, the plugging sleeve 3 descends to the lower annular cavity of the sealing tool, and the high-pressure fluid can pass through the overflow hole 5 on the upper cylinder 1 to perform sand flushing and well washing operations around the construction position. It has the characteristics of simple structure, large traction and reliable operation.

Claims

1. A hydraulic reciprocating tractor, comprising an upper cylinder (1), characterized in that: An upper piston (6) is provided in the middle of the upper cylinder (1), the lower portion of the upper piston (6) is fixedly connected to a telescopic tube (7), a liquid hole B (49) is provided on the top of the telescopic tube (7), the lower portion of the upper cylinder (1) is connected to a cylinder cover (8) through a threaded seal, the telescopic tube (7) is connected to the inner hole of the cylinder cover (8) through a sealing ring, and the telescopic tube (7) is connected to an anchoring mechanism (9) after extending out of the cylinder cover (8); The inner hole of the upper piston (6) is sealed and connected to the guide tube (11). The guide tube (11) extends downward for a distance. The lower part of the guide tube (11) is connected to the limit rod (13) through the long hole D (50). The inner hole of the telescopic tube (7) is larger than the inner hole of the upper piston (6). There is a step surface (14) between the inner hole of the telescopic tube (7) and the inner hole of the upper piston (6). The length of the limit rod (13) is larger than the inner hole diameter of the upper piston (6). The upper part of the guide tube (11) is threadedly connected to the adapter sleeve (15). The adapter sleeve (15) is fixedly connected to the adapter cap (23) and the upper cylinder (1); The upper portion of the upper cylinder (1) is provided with an outer valve hole (33) and an inner valve hole (34), the outer valve hole (33) is connected to the outer valve core (17) through a clearance fit, the outer valve core (17) is connected to the inner valve core (16) through a clearance fit, the inner valve core (16) is connected to the inner valve hole (34) through a clearance fit, the upper portion of the inner valve hole (34) is a closed structure, the lower portion of the inner valve hole (34) extends to the adapter cap (23), the upper cylinder (1) is provided with a liquid inlet channel (24) on the left side of the outer valve hole (33), the upper cylinder (1) is provided with an upper drain channel (30) and a lower drain channel (29) on the right side of the outer valve hole (33), the upper cylinder (1) is provided with an upper drain hole (27) and a lower drain hole (28) on the right side of the outer valve hole (33), and the upper drain channel (24) is provided. The channel (30) is connected to the upper drain hole (27), the lower drain hole (29) is connected to the lower drain hole (28), the upper cylinder (1) is provided with an upper bypass pipe (26) and a lower bypass pipe (25), the upper bypass pipe (26) is connected to the upper cylinder (1) above the inner valve hole (34), and the lower part is connected to the outer valve hole (33) at the lower position of the upper drain hole (27), the upper part of the lower bypass pipe (25) is connected to the outer valve hole (33) at the upper position of the lower drain hole (28), and the lower part is connected to the upper cylinder (1) above the upper piston (6), the top of the outer valve hole (33) is provided with upper conversion channels (31) on the left and right sides, and the adapter cap (23) is provided with lower conversion channels (32) on the left and right sides of the bottom of the outer valve hole (33); A ring groove (35) is formed in the middle of the outer valve core (17), and slits (36) are formed on the upper side of the ring groove (35) and are evenly distributed around the circumference of the outer valve core (17); The inner valve core (16) has long holes C (37) on both sides of the left and right sides. The inner valve core (16) has an upper liquid inlet groove (38) on the left side of the upper part and an upper liquid discharge groove (40) on the right side. The inner valve core (16) has a lower liquid inlet groove (43) on the left side of the lower part and a lower liquid discharge groove (41) on the right side. The bottom of the inner valve core (16) has a liquid hole A (42). The top of the inner valve core (16) has two long holes B (22) in the left and right directions. An anti-rotation rod (18) is inserted into the long hole B (22) of the inner valve core (16). Two countersunk holes (39) are opened on the top of the inner valve hole (34). The anti-rotation rod (18) is inserted into the two countersunk holes (39). The limit rod (13) is fixedly connected to the lead rod (12), the top of the lead rod (12) is fixedly connected to the bottom of the inner valve core (16), the middle of the lead rod (12) is fixedly connected to the limit bolt (20), the middle of the lead tube (11) is sleeved with a limit coupling (19), the limit coupling (19) is located on the upper part of the upper piston (6), and the limit bolt (20) passes through the long hole A (21) on the lead tube (11) and is fixedly connected to the limit coupling (19); The anchoring mechanism (9) comprises a lower cylinder (45), the top of the lower cylinder (45) is threadedly sealed and connected to the telescopic tube (7), a lower piston (44) is provided in the lower cylinder (45), the lower piston (44) is connected to the lower cylinder (45) through a sealing ring clearance fit, the lower portion of the lower piston (44) is fixedly connected to a telescopic column (48) with a reduced diameter, the bottom of the lower cylinder (45) is provided with an anchor claw (46) evenly distributed around the circumference, the lower cylinder (45) is hingedly connected to the upper portion of the anchor claw (46), the telescopic column (48) extends out of the lower cylinder (45) and is hingedly connected to a connecting rod (47), the other side of the connecting rod (47) is hingedly connected to the lower portion of the anchor claw (46), and a compression spring is provided between the lower piston (44) and the bottom of the lower cylinder (45).

2. A hydraulic reciprocating tractor according to claim 1, characterized in that: An upper joint (2) is machined on the top of the upper cylinder (1), and the upper cylinder (1) is connected to a plugging sleeve (3) at the lower part of the upper joint (2) through a pin (4). A ball seat hole is machined in the inner hole of the plugging sleeve (3). An overflow hole (5) communicating with the outside is opened at the position of the plugging sleeve (3), and the plugging sleeve (3) covers the overflow hole (5).

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