Experimental device for simulating influence of wettability change on multiphase seepage

Abstract

The invention relates to an experimental device for simulating the influence of wettability change on multiphase seepage, and belongs to the technical field of rock core testing, the experimental device comprises an experimental device body, the experimental device body is composed of a cylinder, a rubber sleeve arranged in the cylinder, a chock plug slidably arranged in the rubber sleeve and a through pipe fixedly communicated with the outer surface of the chock plug and extending to the outside of the cylinder, a connecting disc fixed with one end of the rubber sleeve is detachably mounted on one side of the barrel; a piston mechanism which extends into the rubber sleeve and is used for driving the chock plug is arranged on the outer surface of the cylinder body; the piston mechanism comprises a first piston cylinder fixed to the outer surface of the cylinder body and a second piston cylinder detachably installed in the rubber sleeve. And a linkage structure is arranged between the rotating shaft and the first push rod. The experimental device for simulating the influence of the wettability change on the multiphase seepage is driven by the electric telescopic rod, manual intervention is reduced, the experimental device is suitable for high-frequency experiments, the piston mechanism provides stable clamping force, linkage winding and synchronous adjustment of wetting medium flow are achieved, and manual operation errors are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of core testing, and specifically provides an experimental device for simulating the influence of wettability change on multiphase seepage. Background Technique

[0002] The experimental device for simulating the influence of wettability change on multiphase seepage is usually a multiphase seepage experimental system, whose core is a core displacement device, combined with a wettability regulation module and a monitoring system. The core components of the experimental device are: a core holder, which is used to fix the porous medium and simulate the underground reservoir conditions. Usually equipped with a confining pressure pump to apply radial stress and simulate the formation pressure. A multi-channel injection pump: precisely control the injection speed and proportion of fluids such as oil, water, and gas. A wettability modifier injection unit: used to inject surfactants, nanofluids, ionic solutions, etc. to change the wettability of the core.

[0003] After retrieval, the patent document with the publication number CN218726469U discloses a core holder suitable for wettability adjustment of tight sandstone, including a left cylinder and a right cylinder, and the left cylinder and the right cylinder are detachably connected. It also includes: a first connecting disk, fixedly connected to the outer wall of the left cylinder; a second connecting disk, fixedly connected to the outer wall of the right cylinder, and a plug rod is fixedly connected to the second connecting disk; a groove is embedded and opened on the plug rod, a clamping block is slidably connected in the groove, and a first spring is arranged between the clamping block and the groove; this application can facilitate the quick disassembly and installation of the left cylinder and the right cylinder, and then can facilitate the removal of the core body after the permeability test of the core body is completed, and can facilitate the replacement of the rubber sleeve when it is severely worn, and can adjust the distance between the two sets of plug heads according to the length of the core body.

[0004] However, the above patent still has the following defects: such as insufficient operation efficiency, relying on a rocker to manually rotate the lead screw to adjust the distance between the plug heads, with low efficiency for a large number of core tests, and the lead screw drive is prone to pollution. The lead screw is exposed to the humid environment of the annular cavity, and long-term use may cause thread corrosion or jamming.

[0005] Therefore, it is urgent to improve the above core holder to solve the existing problems. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the present invention provides an experimental device for simulating the influence of wettability change on multiphase seepage, which has the advantages of good clamping effect and high detection efficiency, and solves the problems that the existing core holder has low efficiency in adjusting the position of the plug head by manually rotating the lead screw, and the lead screw is also prone to pollution.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an experimental device for simulating the effect of wettability change on multiphase seepage, comprising an experimental device, the experimental device comprising a cylinder, a rubber sleeve arranged inside the cylinder, a plug slidably arranged inside the rubber sleeve, and a through pipe fixedly connected to the outer surface of the plug and extending to the outside of the cylinder, a connecting plate fixed to one end of the rubber sleeve being detachably mounted on one side of the cylinder;

[0008] The outer surface of the cylinder is provided with a piston mechanism extending into the rubber sleeve for driving the plug;

[0009] The piston mechanism comprises a first piston cylinder fixed to the outer surface of the cylinder body and a second piston cylinder detachably mounted in the rubber sleeve, wherein piston blocks are arranged inside the first piston cylinder and the second piston cylinder, a first push rod extending outside the piston block is rotatably arranged on the upper surface of the piston block inside the first piston cylinder, a second push rod fixed to the plug head is fixed on the outer surface of the piston block inside the second piston cylinder, and a driving structure for driving the first push rod is arranged on the outer surface of the first piston cylinder;

[0010] A winding structure for winding the through pipe is arranged outside the first piston cylinder, and the winding structure comprises a rotating shaft arranged outside the first piston cylinder and a winding wheel fixed to the outer surface of the rotating shaft;

[0011] A linkage structure is arranged between the rotating shaft and the first push rod.

[0012] Furthermore, the interior of the cylinder is hollow, and a connecting flange is welded to one end of the cylinder away from the connecting plate. There are two cylinders, and the two cylinders are butt-jointed via the connecting flange.

[0013] Furthermore, a sealing disk is arranged inside the cylinder, the rubber sleeve passes through the sealing disk, one end of the rubber sleeve is fixed to the connecting disk by bolts, and two water pipes distributed up and down are fixedly installed inside the cylinder.

[0014] Furthermore, the interior of the plug head is hollow, and a spray hole is provided on a side of the plug head away from the second push rod.

[0015] Furthermore, a ventilation pipe is detachably installed between the first piston cylinder and the second piston cylinder, and the ventilation pipe runs through the interior of the connecting disk.

[0016] Furthermore, the driving structure includes an electric telescopic rod fixed to the outer surface of the first piston cylinder, and a connecting plate rotatably connected to the first push rod is fixed to the output end of the electric telescopic rod.

[0017] Furthermore, a mounting seat is fixed on the upper surface of the first piston cylinder, the interior of the mounting seat is hollow and the top is open, and the first push rod passes through the interior of the mounting seat.

[0018] Furthermore, an installation platform is fixed on the outer surface of the top end of the first piston cylinder, and the rotating shaft bearing is installed on the upper surface of the installation platform.

[0019] Furthermore, the linkage structure includes a transmission gear fixed to the top end of the first push rod, a driven gear fixed to the top end of the rotating shaft and meshing with the transmission gear, and a guiding member disposed inside the mounting seat and connected to the inside of the first push rod.

[0020] Furthermore, the guiding member includes an elastic rod fixed inside the mounting seat and a ball rotating at one end of the elastic rod close to the first push rod. A guiding chute adapted to the ball is provided inside the first push rod. The guiding chute is arranged in a spiral shape around the outer surface of the first push rod, and the ball is in rolling connection with the inner side of the guiding chute.

[0021] Compared with the prior art, the present invention provides an experimental device for simulating the influence of wettability change on multiphase seepage, having the following beneficial effects:

[0022] 1. The experimental device for simulating the influence of wettability change on multiphase seepage is driven by an electric telescopic rod, reducing manual intervention and being suitable for high-frequency experiments. The piston mechanism provides a stable clamping force, and the linkage winding synchronously adjusts the flow rate of the wetting medium, avoiding manual operation errors.

[0023] 2. The experimental device for simulating the influence of wettability change on multiphase seepage transmits pressure through gas or liquid. The ventilation pipe connects the two piston cylinders, isolating external pollution, and transmitting it into the second piston cylinder through the first piston cylinder to achieve a pushing effect, avoiding mechanical rigid impact damage to the core and realizing flexible clamping.

[0024] 3. The experimental device for simulating the influence of wettability change on multiphase seepage converts the linear motion of the first push rod into a rotational motion through a spiral chute, driving the winding wheel to adjust the length of the through pipe. Different media are injected through the through pipe, and the wettability change of the core is observed in real time. Then, water is injected through the water pipe to simulate the confining pressure, being closer to the real formation conditions and realizing the multiphase seepage simulation ability.

[0025] 4. The experimental device for simulating the influence of wettability change on multiphase seepage converts the linear motion of the piston into the rotational motion of the winding wheel through the linkage structure of gear transmission and spiral guiding chute, realizing the precise coordination of the automatic adjustment of the through pipe length and the displacement of the plug head. Among them, the up-and-down linear motion of the first push rod drives the transmission gear to rotate through the cooperation of the spiral guiding chute and the ball, and then drives the driven gear and the winding wheel to rotate. Without additional motor control, the displacement of the plug head and the winding and unwinding of the through pipe are strictly synchronized, avoiding the interruption of liquid injection caused by the winding or pulling of the through pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a three-dimensional structural view of an experimental device for simulating the influence of wettability change on multiphase seepage according to the present invention;

[0027] Figure 2 This is a structural sectional view of the cylinder in an experimental device for simulating the influence of wettability change on multiphase seepage according to the present invention;

[0028] Figure 3 This is a schematic structural view of the first piston cylinder in an experimental device for simulating the influence of wettability change on multiphase seepage according to the present invention;

[0029] Figure 4 This is a schematic structural view of the plug head in an experimental device for simulating the influence of wettability change on multiphase seepage according to the present invention;

[0030] Figure 5 This is an experimental device for simulating the influence of wettability change on multiphase seepage according to the present invention Figure 3 The enlarged structural view of A shown.

[0031] In the figure: 1. Cylinder; 2. Connecting flange; 3. Rubber sleeve; 4. Connecting plate; 5. Plug head; 51. Spray hole; 6. Sealing plate; 7. Water pipe; 8. Connecting pipe; 9. First piston cylinder; 10. First push rod; 11. Piston block; 12. Second piston cylinder; 13. Vent pipe; 14. Second push rod; 15. Electric telescopic rod; 16. Connecting plate; 17. Mounting seat; 18. Reel; 19. Rotating shaft; 20. Driving gear; 21. Driven gear; 22. Mounting table; 23. Elastic rod; 24. Ball; 25. Guide chute. Detailed implementation manners

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0033] Please refer to Figures 1 to 5, An experimental device for simulating the influence of wettability change on multiphase seepage in this embodiment includes an experimental device, which is composed of a cylinder body 1, a rubber sleeve 3 arranged inside the cylinder body 1, a plug 5 slidably arranged inside the rubber sleeve 3, and a through pipe 8 fixedly connected to the outer surface of the plug 5 and extending to the outside of the cylinder body 1. A connection disk 4 fixed to one end of the rubber sleeve 3 is detachably installed on one side of the cylinder body 1; the inside of the cylinder body 1 is hollow, and a connection flange 2 is welded to the end of the cylinder body 1 away from the connection disk 4. The number of the cylinder bodies 1 is two, and the two cylinder bodies 1 are butt - installed through the connection flange 2. The quick docking and separation of the two cylinder bodies 1 are realized through the connection flange 2, which is convenient for the placement and removal of cores such as tight sandstone. Specifically, a sealing disk 6 is arranged inside the cylinder body 1, and the rubber sleeve 3 penetrates through the inside of the sealing disk 6. The rubber sleeve 3 penetrates through the sealing disk 6 to form a double - seal barrier to prevent the high - pressure water formed by injecting water into the annular cavity through the water pipe 7 from leaking, realizing high - pressure tightness. One end of the rubber sleeve 3 is fixed to the connection disk 4 by bolts, and two water pipes 7 are fixedly installed inside the cylinder body 1 in an up - and - down distribution. Among them, the inside of the plug 5 is hollow, and a spray hole 51 is opened on the side of the plug 5 away from the second push rod 14. The through pipe 8 is composed of two parts. One part of the through pipe 8 is a hard pipe, and the other part is a flexible pipe, and the flexible pipe is rotatably arranged with the hard pipe. One end of the flexible pipe away from the hard pipe is installed with a three - way pipe or a multi - way pipe.

[0034] It should be noted that the elastic material of the rubber sleeve 3, such as fluororubber, can shrink uniformly when injecting water and pressurizing, tightly wrapping the core to avoid core rupture caused by local stress concentration. The design of the double water pipes 7 distributed up and down has the following advantages: Uniform confining pressure simulation: The double water pipes 7 can inject water from both the upper and lower ends simultaneously, making the pressure distribution in the annular cavity more uniform and more truly simulating the formation confining pressure. Multiphase fluid control: If water is injected into the upper water pipe and oil or chemical reagent is injected into the lower water pipe, the oil - water two - phase seepage can be simulated; if the flow rates of the double water pipes are independently controlled, the anisotropic seepage characteristics of heterogeneous cores can be studied.

[0035] In this embodiment, a piston mechanism for driving the plug 5 is arranged on the outer surface of the cylinder body 1 and extends into the rubber sleeve 3; the piston mechanism includes a first piston cylinder 9 fixed to the outer surface of the cylinder body 1 and a second piston cylinder 12 detachably installed inside the rubber sleeve 3. Piston blocks 11 are arranged inside both the first piston cylinder 9 and the second piston cylinder 12. A first push rod 10 extending to the outside is rotatably arranged on the upper surface of the piston block 11 inside the first piston cylinder 9. A second push rod 14 fixed to the plug 5 is fixed to the outer surface of the piston block 11 inside the second piston cylinder 12. A driving structure for driving the first push rod 10 is arranged on the outer surface of the first piston cylinder 9; specifically, the driving structure includes an electric telescopic rod 15 fixed to the outer surface of the first piston cylinder 9, and a connecting plate 16 fixedly connected to the output end of the electric telescopic rod 15 and rotatably connected to the first push rod 10. The electric telescopic rod 15 replaces manual operation to achieve automatic setting. The first push rod 10 and the connecting plate 16 are rotatably connected, allowing slight deflection to avoid jamming of the piston block 11.

[0036] Among them, an air vent pipe 13 is detachably installed between the first piston cylinder 9 and the second piston cylinder 12. The air vent pipe 13 is designed to be detachable, which is convenient for maintaining or replacing the hydraulic pipeline. The air vent pipe 13 penetrates through the inside of the connecting disc 4. The first piston cylinder 9 compresses gas / liquid, and transmits the pressure to the second piston cylinder 12 through the air vent pipe 13, avoiding mechanical rigid impact from damaging the brittle core and achieving flexible clamping. Moreover, the second piston cylinder 12 is built into the rubber sleeve 3 to be isolated from the core environment, preventing the piston seal ring from being worn by rock debris. The upper surface of the first piston cylinder 9 is fixed with a mounting seat 17. The inside of the mounting seat 17 is hollow and its top is open. The first push rod 10 penetrates through the inside of the mounting seat 17. The outer surface of the top end of the first piston cylinder 9 is fixed with a mounting table 22. The rotating shaft 19 is installed on the upper surface of the mounting table 22 by bearings. Gas pressure transmission is connected through the air vent pipe 13, which can be compatible with high-temperature and high-pressure experiments, avoiding the influence of hydraulic oil thermal expansion on the accuracy.

[0037] It should be noted that the hollow structure of the mounting seat 17 provides vertical guidance for the first push rod 10, preventing the sealing ring from being worn due to the swing of the piston rod. At the same time, the open top of the mounting seat 17 is convenient for observing the movement state of the push rod and serves as a vent hole to balance the air pressure. The rotating shaft 19 supported by the mounting table 22 can be linked with other functional modules such as the winding wheel 18 to achieve synchronization of clamping and wetting adjustment. Moreover, the rotating shaft 19 installed by bearings reduces the rotational friction, ensuring smooth meshing of the driving gear 20 and the driven gear 21.

[0038] In addition, a pressure sensor is integrated inside the second piston cylinder 12 to close-loop control the thrust of the electric telescopic rod 15 to achieve an intelligent feedback effect. The surface of the piston block 11 is nickel-plated or made of ceramic material to adapt to acidic media.

[0039] In this embodiment, a winding structure for winding the through pipe 8 is provided outside the first piston cylinder 9. The winding structure includes a rotating shaft 19 provided outside the first piston cylinder 9 and a winding wheel 18 fixed to the outer surface of the rotating shaft 19. A linkage structure is provided between the rotating shaft 19 and the first push rod 10. Specifically, the linkage structure includes a driving gear 20 fixed to the top end of the first push rod 10, a driven gear 21 fixed to the top end of the rotating shaft 19 and meshing with the driving gear 20, and a guiding member provided in the mounting seat 17 and connected to the inside of the first push rod 10. Among them, the guiding member includes an elastic rod 23 fixed to the inside of the mounting seat 17 and a ball 24 rotating at one end of the elastic rod 23 close to the first push rod 10. A guiding chute 25 adapted to the ball 24 is provided inside the first push rod 10. The guiding chute 25 is arranged in a spiral shape around the outer surface of the first push rod 10. The elastic rod 23 allows the ball 24 to slightly rebound when the resistance is too large, avoiding gear jamming. The ball 24 is in rolling connection with the inner side of the guiding chute 25. It should be noted that through the linkage structure of gear transmission and the spiral guiding chute 25, the linear motion of the piston is converted into the rotational motion of the winding wheel 18, realizing the precise coordination of the automatic adjustment of the length of the through pipe 8 and the displacement of the plug 5. Among them, the up-and-down linear motion of the first push rod 10 drives the driving gear 20 to rotate through the cooperation of the spiral guiding chute 25 and the ball 24, and then drives the driven gear 21 and the winding wheel 18 to rotate. Without additional motor control, the displacement of the plug 5 is strictly synchronized with the winding and unwinding of the through pipe 8, avoiding the interruption of liquid injection caused by the winding or pulling of the through pipe. A torque sensor can also be installed on the winding wheel 18 to monitor the tension of the through pipe 8 in real time to prevent breakage due to over-tightening.

[0040] It is worth mentioning that by replacing the driving gear 20 and the driven gear 21 with different numbers of teeth, the rotation speed of the winding wheel 18 can be adjusted to adapt to the diameter requirements of different through pipes 8, such as slow winding for thick pipes and fast winding for thin pipes. When the first push rod 10 moves upward, the winding wheel 18 releases the through pipe 8, and when it moves downward, it tightens, realizing full-stroke control.

[0041] The working principle of the above embodiment is as follows:

[0042] First, the core sample is placed inside the rubber sleeve 3, the two cylinders 1 are butted through the connecting flange 2, and then the electric telescopic rod 15 is started to push the first push rod 10 downward, driving the piston block 11 in the first piston cylinder 9 to compress gas or liquid. The pressure is transmitted to the second piston cylinder 12 through the ventilation pipe 13, pushing the second push rod 14 and the plug 5 toward the core to achieve clamping;

[0043] When the first push rod 10 moves downward, through the interaction between the spiral guiding chute 25 and the ball 24, the driving gear 20 is driven to rotate, driving the driven gear 21 and the rotating shaft 19 to rotate, and the winding wheel 18 rotates synchronously to tighten or release the through pipe 8, adjusting the flow rate of the wetting medium water / oil through the spray hole 51;

[0044] Next, water is injected into the annular cavity between the outer wall of the rubber sleeve 3 and the cylinder body 1 through the water pipe 7 to simulate the formation pressure, and a wetting medium such as a chemical reagent is injected through the pipe 8. The change in the core permeability is observed. After the experiment is completed, the electric telescopic rod 15 is reset, the piston mechanism is depressurized, and the connecting flange 2 is disassembled to take out the core for analysis.

[0045] The installation method, connection method or setting method disclosed in this embodiment are all common mechanical connection methods, and any method that can achieve its beneficial effects can be implemented. In addition, the electrical components in this embodiment are all electrically connected to the main controller and the power supply. The main controller can be a conventional known device such as a computer that plays a control role. Those skilled in the art can realize the control of the electrical components through simple programming, and the existing publicly disclosed power connection technology also belongs to the common knowledge in this field. Therefore, the specific structural composition and working principle will not be described in detail in this embodiment.

[0046] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0047] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An experimental device for simulating the influence of wettability change on multiphase seepage, including an experimental device, characterized in that: The experimental device comprises a cylinder (1), a rubber sleeve (3) arranged inside the cylinder (1), a plug (5) slidably arranged inside the rubber sleeve (3), and a through pipe (8) fixedly connected to the outer surface of the plug (5) and extending to the outside of the cylinder (1); a connecting plate (4) fixed to one end of the rubber sleeve (3) is detachably mounted on one side of the cylinder (1); The outer surface of the cylinder (1) is provided with a piston mechanism extending into the interior of the rubber sleeve (3) for driving the plug (5); The piston mechanism comprises a first piston cylinder (9) fixed to the outer surface of the cylinder body (1) and a second piston cylinder (12) detachably mounted in the rubber sleeve (3); a piston block (11) is arranged inside the first piston cylinder (9) and the second piston cylinder (12); a first push rod (10) extending outside the piston block (11) is rotatably arranged on the upper surface of the piston block (11) inside the first piston cylinder (9); a second push rod (14) fixed to the plug (5) is fixed on the outer surface of the piston block (11) inside the second piston cylinder (12); and a driving structure for driving the first push rod (10) is arranged on the outer surface of the first piston cylinder (9); A winding structure for winding the through pipe (8) is arranged outside the first piston cylinder (9), and the winding structure comprises a rotating shaft (19) arranged outside the first piston cylinder (9) and a winding wheel (18) fixed to the outer surface of the rotating shaft (19); A linkage structure is provided between the rotating shaft (19) and the first push rod (10).

2. The experimental device for simulating the influence of wettability change on multiphase seepage according to claim 1, wherein: The interior of the cylinder (1) is hollow, and a connecting flange (2) is welded to one end of the cylinder (1) away from the connecting plate (4). There are two cylinders (1), and the two cylinders (1) are butt-jointed and installed via the connecting flange (2).

3. An experimental device for simulating the influence of wettability change on multiphase seepage according to claim 1, characterized in that: A sealing disk (6) is arranged inside the cylinder (1), the rubber sleeve (3) passes through the sealing disk (6), one end of the rubber sleeve (3) is fixed to the connecting disk (4) by means of bolts, and two water pipes (7) distributed up and down are fixedly installed inside the cylinder (1).

4. An experimental device for simulating the influence of wettability change on multiphase seepage according to claim 1, characterized in that: The plug head (5) is hollow inside, and a spray hole (51) is provided on a side of the plug head (5) away from the second push rod (14).

5. An experimental device for simulating the influence of wettability change on multiphase seepage according to claim 1, characterized in that: A vent pipe (13) is detachably mounted between the first piston cylinder (9) and the second piston cylinder (12), and the vent pipe (13) runs through the interior of the connecting disk (4).

6. An experimental device for simulating the influence of wettability change on multiphase seepage according to claim 1, characterized in that: The driving structure comprises an electric telescopic rod (15) fixed to the outer surface of the first piston cylinder (9), and a connecting plate (16) rotatably connected to the first push rod (10) is fixed to the output end of the electric telescopic rod (15).

7. An experimental device for simulating the influence of wettability change on multiphase seepage according to claim 1, characterized in that: A mounting seat (17) is fixed on the upper surface of the first piston cylinder (9); the interior of the mounting seat (17) is hollow and the top is open; the first push rod (10) passes through the interior of the mounting seat (17).

8. An experimental device for simulating the influence of wettability change on multiphase seepage according to claim 1, characterized in that: A mounting platform (22) is fixed to the outer surface of the top end of the first piston cylinder (9), and the bearing of the rotating shaft (19) is mounted on the upper surface of the mounting platform (22).

9. An experimental device for simulating the influence of wettability change on multiphase seepage according to claim 7, characterized in that: The linkage structure includes a transmission gear (20) fixed to the top end of the first push rod (10), a driven gear (21) fixed to the top end of the rotating shaft (19) and meshing with the transmission gear (20), and a guide member disposed inside the mounting seat (17) and internally connected to the first push rod (10).

10. An experimental device for simulating the influence of wettability change on multiphase seepage according to claim 9, characterized in that: The guide member includes an elastic rod (23) fixed inside the mounting seat (17) and a ball (24) rotating at one end of the elastic rod (23) close to the first push rod (10). A guide chute (25) adapted to the ball (24) is formed inside the first push rod (10). The guide chute (25) is arranged in a spiral shape around the outer surface of the first push rod (10), and the ball (24) is in rolling connection with the inner side of the guide chute (25).

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