Pipeline and pipeline cooling method

Abstract

A pipeline and a pipeline cooling method, comprising a pipeline and side sealing plates installed at outlets on both sides of the pipeline, the side sealing plates and the pipeline forming a closed chamber, a first input port and a second input port are provided on the side sealing plates, a spiral tube is provided between the two first input ports, the distance between the spiral tube and the inner wall of the pipeline is less than one tenth of the diameter of the inner wall of the pipeline, the side sealing plates comprise a fixing ring and a buffer ring, and the fixing ring is detachably connected to the pipeline. The present invention increases the cooling area and cooling time of liquid nitrogen in the pipeline by arranging a spiral pipeline in the pipeline, thereby improving the cooling effect, so that the temperature in the pipeline is quickly reduced to reach the temperature required for the pipeline explosion experiment.

Description

Technical Field

[0001] The invention relates to the technical field of pipeline mechanics, and in particular to a pipeline and a pipeline cooling method. Background Art

[0002] my country's infrastructure is developing rapidly. The West-East Gas Transmission Project and the West-East Electricity Transmission Project are both major infrastructure projects in my country. The West-East Gas Transmission Project requires special pipelines that can ensure rigidity and stability at minus 30-60 degrees Celsius. Steel pipes are prone to brittle cracking when they are in a low temperature state for a long time. After being subjected to external impact, the pipe structure becomes more unstable. Once the crack becomes larger, it will cause a large amount of combustible gas to overflow, which will have a serious impact on the surrounding ecological environment and the lives of residents. Therefore, a large number of tests are required before the pipeline is put into use. Before the test, the pipeline needs to be cooled under high pressure. The traditional gas cooling method is difficult to quickly cool the pipeline to minus 30-60 degrees Celsius. Therefore, according to this situation, a pipeline and pipeline cooling method need to be designed. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a pipeline and a pipeline cooling method.

[0004] The present invention solves the technical problem by adopting the following technical solutions:

[0005] A pipeline comprises a pipeline and side sealing plates installed at outlets on both sides of the pipeline, the side sealing plates and the pipeline form a closed chamber, the side sealing plates are provided with a first input port and a second input port, a spiral tube is provided between the two first input ports, the distance between the spiral tube and the inner wall of the pipeline is less than one tenth of the diameter of the inner wall of the pipeline, the side sealing plates comprise a fixed ring and a buffer ring, the fixed ring is detachably connected to the pipeline, the fixed ring is provided with a first protrusion slidably connected to the outer ring wall of the buffer ring, the buffer ring is provided with a second protrusion slidably connected to the inner ring wall of the fixed ring, a closed first chamber is formed between the fixed ring, the buffer ring, the first protrusion and the second protrusion, a first buffer assembly is provided in the first chamber, during explosion, the first buffer assembly provides the buffer ring with a buffer force opposite to the impact force of the explosion on the buffer ring, the inner ring of the buffer ring is provided with a plurality of water-blocking valves.

[0006] Preferably, it also includes a fixing mechanism and a driving mechanism located on the side sealing plate, the fixing mechanism includes a limit groove arranged on the outer ring surface of the fixing ring, an annular cavity is provided in the steel pipe, a limit block adapted to the limit groove is provided in the annular cavity, a first elastic member is provided between the limit block and the annular cavity, the driving mechanism includes a driving motor and two directional rotating wheels located in the sliding cavity, the output end of the driving motor is connected to the two free ends of the tensioning cable, and the tensioning cable is slidably connected to the limit block in the annular cavity via the two directional rotating wheels.

[0007] Preferably, the buffer ring includes a first buffer ring and a second buffer ring, the outer ring wall of the second buffer ring is slidably connected to the fixed ring, the second protrusion is located on the second buffer ring, the water-blocking valve is located on the inner ring of the first buffer ring, the inner ring wall of the second buffer ring is provided with a third protrusion slidably connected to the outer ring wall of the first buffer ring, the outer ring wall of the first buffer ring is provided with a fourth protrusion slidably connected to the inner ring wall of the second buffer ring, a closed second chamber is formed between the first buffer ring, the second buffer ring, the third protrusion and the fourth protrusion, a second buffer assembly is provided in the second chamber, during explosion, the second buffer assembly provides the first buffer ring with a buffer force opposite to the impact force generated by the explosion on the first buffer ring, an inflatable membrane is provided on one side of the first buffer ring in the pipeline, and a cross-shaped notch is provided at a position of the inflatable membrane corresponding to the inner circular ring of the second buffer ring.

[0008] Preferably, a through cavity is provided on the second buffer ring, the through cavity communicates with the first chamber and the second chamber, and a two-way valve is provided in the through cavity.

[0009] Preferably, the fixing ring is provided with a first slide groove on the side facing the inside of the pipe, the first slide groove is provided with an opening on the side facing the pipe, a slider is provided in the first slide groove on the side away from the first slide groove opening, the slider penetrates through a side wall of the slider adjacent to the first chamber, enters the first chamber and is slidably connected to the fixing ring, a second elastic member is provided on the side of the slider away from the first chamber, a first rotating shaft and a second rotating shaft are provided in the first slide groove, the first rotating shaft and the second rotating shaft are respectively rotatably connected to a first shaft rod and a second shaft rod, one end of the first shaft rod is hinged to the slider, a second slide groove is provided at one end of the second shaft rod, the other end of the first shaft rod is slidably connected to the second slide groove of the second shaft rod, and a friction block is provided at the other end of the second shaft rod.

[0010] Preferably, the first buffer assembly includes a first spring connected to the first protrusion and the second protrusion and a first buffer disposed in the first chamber, the second buffer assembly includes a second spring connected to the third protrusion and the fourth protrusion and a second buffer disposed in the second chamber, and the first elastic member and the second elastic member are both springs.

[0011] A pipeline cooling method comprises the following steps:

[0012] Step 1: Lay the pipe flat and install side sealing plates on both sides of the pipe, and adjust the spiral pipe to the position farthest from the ground;

[0013] Step 2: liquid methanol is introduced into the pipeline through the second input port, the liquid methanol is 85%-92% of the volume of the pipeline, and gaseous methanol is introduced into the pipeline through the second input port to fill the remaining space;

[0014] Step 3: Liquid nitrogen is continuously injected into the spiral tube through the first input port to cool the gaseous methanol.

[0015] The advantages and positive effects of the present invention are:

[0016] 1. The present invention increases the cooling area and cooling time of the liquid nitrogen in the pipeline by arranging a spiral pipeline in the pipeline, thereby improving the cooling effect, so that the temperature in the pipeline is quickly reduced to reach the detection temperature required for blasting.

[0017] 2. The present invention replaces all liquid methanol with a mixture of liquid methanol and gas, and then rapidly cools the gaseous methanol through a spiral tube and liquid nitrogen to reach minus 30-60 degrees Celsius, thereby meeting the test standard and improving the test accuracy.

[0018] 3. The present invention improves the buffering force through the first buffer assembly in the first chamber, avoiding the rigid collision between the buffer ring and the fixed ring. The water-blocking valve can ensure that when the impact force in the pipeline is large, the methanol can be actively discharged to reduce the impact force on the side sealing plate.

[0019] 4. The present invention buffers the impact on the side sealing plate by means of the buffer ring and the first chamber arranged on the side sealing plate, simulating the state in which the natural gas in the pipeline disperses force to both sides after being impacted in actual conditions, thereby reducing the impact force on the side sealing plate and improving the precision of explosion detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is an axial schematic diagram of the present invention;

[0021] Figure 2 It is a schematic diagram of a front cross-sectional view of the present invention;

[0022] Figure 3is a side sectional view of a side sealing plate of the present invention;

[0023] Figure 4 is an axonometric view of a side sealing plate of the present invention;

[0024] Figure 5 It is a structural schematic diagram of the friction block in the first chute of the present invention.

[0025] In the figure: 1. pipeline; 2. side sealing plate; 3. first input port; 4. second input port; 5. spiral tube; 6. first protrusion; 7. second protrusion; 8. first chamber; 9. first buffer assembly; 10. water-blocking valve; 11. limiting groove; 12. annular cavity; 13. limiting block; 14. first elastic member; 15. directional rotating wheel; 16. driving motor; 17. tensioning cable; 18. first buffer ring; 19. second buffer ring; 20. third protrusion; 21. fourth protrusion; 22. second chamber; 23. second buffer assembly; 24. inflatable membrane; 25. cross-shaped recess; 26. through cavity; 27. two-way valve; 28. first slide groove; 29. ​​slider; 30. second elastic member; 31. first rotating shaft; 32. second rotating shaft; 33. first shaft rod; 34. second shaft rod; 35. second slide groove; 36. friction block; 37. fixing ring. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a component centered. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a component centered. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a component centered. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0029] The embodiments of the present invention are further described in detail below with reference to the accompanying drawings:

[0030] like Figure 1 and Figure 2 As shown, a pipeline 1 blasting device and a blasting test cooling method of the present invention include a pipeline 1 and side sealing plates 2 installed at the outlets on both sides of the pipeline 1. The side sealing plates 2 block the outlets on both sides of the pipeline 1 to form a closed space inside the pipeline 1. The side sealing plates 2 and the pipeline 1 form a closed chamber. The side sealing plates 2 are provided with a first input port 3 and a second input port 4. The first input port 3 and the second input port 4 are both provided with valves. A spiral tube 5 is provided between the two first input ports 3. The distance between the spiral tube 5 and the inner wall of the pipeline 1 is less than one tenth of the diameter of the inner wall of the pipeline 1. First, the spiral tube 5 increases the residence time of the liquid nitrogen in the pipeline and increases the cooling area, thereby improving the cooling effect, so that the liquid nitrogen can quickly cool the liquid inside the pipeline 1 through the spiral tube 5. Here, the spiral tube 5 can be selected in a multi-pass manner, and the pipeline is cooled by multiple spiral rods 5 at the same time, further improving the cooling effect, so that the cooling efficiency is maximized, and then ensuring that after the liquid methanol is input, the liquid methanol will not submerge the spiral tube 5. The side sealing plate 2 includes a fixing ring 37 and a buffer ring. The fixing ring 37 is fixed to the pipeline 1 by a fixing mechanism, such as Figure 3 As shown, the fixing mechanism enables the fixing ring 37 to be detachably connected to the pipeline 1, and the fixing mechanism includes a limiting groove 11 arranged on the outer ring surface of the fixing ring 37, an annular cavity 12 is arranged in the steel pipe, and a limiting block 13 adapted to the limiting groove 11 is arranged in the annular cavity 12, and the limiting block 13 enters the limiting groove 11 to fix the fixing ring 37, and a first elastic member 14 is arranged between the limiting block 13 and the annular cavity 12, where the first elastic member 14 is a spring, and the driving mechanism includes a driving motor 16 and two directional wheels 15 located in the sliding cavity, and the directional wheels 15 are symmetrically arranged, and the output end of the driving motor 16 is connected to the two free ends of the tensioning cable 17, and the free end of the tensioning cable 17 passes between the two directional wheels 15 and is sleeved on the limiting block 13, and the tensioning cable 17 is slidably connected to the limiting block 13 in the annular cavity 12 through the two directional wheels 15.

[0031] like Figure 2As shown, the fixed ring 37 is provided with a first protrusion 6 which is slidably connected to the outer ring wall of the buffer ring, and the buffer ring is provided with a second protrusion 7 which is slidably connected to the inner ring wall of the fixed ring 37. A closed first chamber 8 is formed between the fixed ring 37, the buffer ring, the first protrusion 6 and the second protrusion 7. A first buffer assembly 9 is provided in the first chamber 8. The first buffer assembly 9 includes a first spring connected to the first protrusion 6 and the second protrusion 7 and a first buffer arranged in the first chamber 8. During explosion, the first buffer assembly 9 provides the buffer ring with a buffer force opposite to the impact force of the explosion on the buffer ring. The inner ring of the buffer ring is provided with a plurality of water-blocking valves 10. When the water-blocking valve 10 is subjected to water pressure shock, methanol overflows from the water-blocking valve 10 to reduce the impact force in the pipeline 1.

[0032] like Figure 2 and Figure 4 As shown, the buffer ring includes a first buffer ring 18 and a second buffer ring 19, thereby forming a multi-stage buffer to reduce the impact force of the explosion on the side sealing plate 2. The outer ring wall of the second buffer ring 19 is slidably connected to the fixed ring 37, the second protrusion 7 is located on the second buffer ring 19, the water-blocking valve 10 is located on the inner ring of the first buffer ring 18, and the inner ring wall of the second buffer ring 19 is provided with a third protrusion 20 slidably connected to the outer ring wall of the first buffer ring 18, and the outer ring wall of the first buffer ring 18 is provided with a fourth protrusion 21 slidably connected to the inner ring wall of the second buffer ring 19, and a closed second chamber 22 is formed between the first buffer ring 18, the second buffer ring 19, the third protrusion 20 and the fourth protrusion 21, and the second buffer ring 19 is provided with a through cavity 26, the through cavity 26 connects the first cavity 8 and the second cavity 22, a two-way valve 27 is provided in the through cavity 26, and a second buffer assembly 23 is provided in the second cavity 22. During explosion, the second buffer assembly 23 provides a buffer force for the first buffer ring 18 that is opposite to the impact force generated by the explosion on the first buffer ring 18. An inflatable membrane 24 is provided on one side of the first buffer ring 18 in the pipeline 1. The inflatable membrane 24 is in an arc shape facing the inside of the pipeline 1, thereby ensuring that the second buffer ring 19 is impacted first. A cross-shaped notch 25 is provided at a position corresponding to the inner ring of the second buffer ring 19, so that when the liquid methanol in the pipeline 1 is subjected to a huge impact, the cross-shaped notch ruptures, and the liquid methanol can flow out from the ruptured cross-shaped notch.

[0033] like Figure 5As shown, a first slide groove 28 is provided on the side of the fixing ring 37 facing the inside of the pipe 1, and an opening is provided on the side of the first slide groove 28 facing the pipe 1. A slider 29 is provided on the side of the first slide groove 28 away from the opening of the first slide groove 28. The slider 29 penetrates a side wall of the slider 29 adjacent to the first chamber 8 and enters the first chamber 8 and is slidably connected with the fixing ring 37. A second elastic member 30 is provided on the side of the slider 29 away from the first chamber 8. The second elastic member 30 is a spring. A first rotating shaft 31 and a second rotating shaft 32 are provided in the first slide groove 28. The first rotating shaft 31 and the second rotating shaft 32 are respectively A first shaft rod 33 and a second shaft rod 34 are rotatably connected, one end of the first shaft rod 33 is hinged to the slider 29, one end of the second shaft rod 34 is provided with a second slide groove 35, the other end of the first shaft rod 33 is slidably connected to the second slide groove 35 of the second shaft rod 34, the distance from the hinge point of the second shaft rod 34 and the second rotating shaft 32 to the end of the first shaft rod 33 adjacent to the second shaft rod 34 is much smaller than the distance from the hinge point to the other end of the second shaft rod 34, the other end of the second shaft rod 34 is provided with a friction block 36, the friction block 36 rubs against the inner wall of the pipe 1 to increase friction and prevent the fixing ring 37 from falling off.

[0034] A pipeline cooling method comprises the following steps:

[0035] Step 1: Lay the pipeline 1 flat and install side sealing plates 2 on both sides of the pipeline 1, adjust the spiral pipe 5 to the position farthest from the ground, at this time the spiral pipe 5 remains horizontal, and the spiral pipe 5 is located in the gaseous methanol when it is farthest from the ground, ensuring the cooling effect on the gaseous methanol;

[0036] Step 2: liquid methanol is input into the pipeline 1 through the second input port 4, and the liquid methanol is 85%-92% of the volume of the pipeline 1. Gaseous methanol is input into the pipeline 1 through the second input port 4 to fill the remaining space. The inside of the pipeline 1 is cooled by liquid methanol and gaseous methanol, 85%-92% of liquid methanol, and the remaining space is filled with gaseous methanol. Gaseous methanol may not be added here, and it is simply a mixture of liquid methanol and gas, which corresponds to the position of the spiral tube 5, ensuring that the spiral tube 5 is in the gaseous methanol (or ordinary gas), quickly cooling the gaseous methanol and then quickly cooling the pipeline 1, increasing the cooling efficiency and cooling effect;

[0037] Step 3: Liquid nitrogen is continuously injected into the spiral tube 5 through the first input port 3, and the liquid nitrogen is output through the first input port 3 on the other side, thereby cooling the gaseous methanol and the liquid methanol to -30-40 degrees Celsius at the same time.

[0038] During the specific implementation, the side sealing plates 2 are installed on both sides of the pipeline 1, and the driving motor 16 is turned on to drive the tensioning cable 17 to tighten. At this time, the limit block 13 on the tensioning cable 17 is subjected to the extrusion force of the tensioning cable 17 toward the center of the fixing ring 37, enters the limit groove 11, and fixes the fixing ring 37. Then, the pipeline 1 is laid flat, and the spiral tube 5 is adjusted to the position farthest from the ground. At this time, the spiral tube 5 remains in a horizontal state, and then liquid methanol is input into the pipeline 1 through the second input port 4. The liquid methanol is 85%-92% of the volume of the pipeline 1. The gaseous methanol is input into the pipeline 1 through the second input port 4 to fill the remaining space. The inside of the pipeline 1 is cooled by the liquid methanol and the gaseous methanol. Liquid nitrogen is continuously injected into the spiral tube 5 through the first input port 3. The liquid nitrogen is output through the first input port 3 on the other side, and the gaseous methanol and the liquid methanol are cooled to minus 30-40 degrees at the same time, thereby reaching the temperature when the transport pipeline 1 is simulated;

[0039] Then, a blasting device is installed on the outside of the pipeline 1 to perform a simulated blasting. During the blasting, the methanol in the pipeline 1 is subjected to an impact force that disperses the impact force to both sides of the pipeline 1. At this time, the inflatable membrane 24 is impacted first, and then the first buffer ring 18 moves to the side away from the center of the pipeline 1, and then the second buffer assembly 23 gives the first buffer ring 18 a buffer force toward the center of the pipeline 1. When the displacement of the first buffer ring 18 reaches the maximum, the first buffer ring 18 drives the second buffer ring 19 to move away from the center of the pipeline 1. At this time, the first buffer assembly 9 gives the second buffer ring 19 a buffer force, thereby providing multiple buffer forces. When the buffer force is greater, the liquid methanol breaks through the cross notch of the inflatable membrane 24 and ejects methanol to the outside of the pipe body through the water-isolating valve 10. The outside of the second pipeline 1 is connected to an outer pipe to collect methanol, thereby reducing the impact force on the side sealing plate 2;

[0040] After the first protrusion 6 slides away from the center of the pipe 1, it presses the slider 29 upward, and then the slider 29 drives one end of the first shaft rod 33 to move upward, and then the other end of the first shaft rod 33 moves downward, driving one end of the second shaft rod 34 to move downward, and then the other end of the second shaft rod 34 drives the friction block 36 to move upward, and the friction block 36 rubs against the inner wall of the pipe 1 to increase the friction force and prevent the fixing ring 37 from falling off.

[0041] It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive, and therefore the present invention is not limited to the embodiments described in the specific implementation manners. Any other implementation manners derived by those skilled in the art based on the technical solutions of the present invention also fall within the scope of protection of the present invention.

Claims

1. A pipeline, comprising a pipeline (1) and side sealing plates (2) installed at outlets on both sides of the pipeline (1), wherein the side sealing plates (2) and the pipeline (1) form a closed chamber, characterized in that: The side sealing plate (2) is provided with a first input port (3) and a second input port (4), a spiral tube (5) is provided between the two first input ports (3), the distance between the spiral tube (5) and the inner wall of the pipe (1) is less than one tenth of the diameter of the inner wall of the pipe (1), the side sealing plate (2) comprises a fixing ring (37) and a buffer ring, the fixing ring (37) is detachably connected to the pipe (1), the fixing ring (37) is provided with a first protrusion (6) slidably connected to the outer ring wall of the buffer ring, the buffer ring is provided with a second protrusion (7) slidably connected to the inner ring wall of the fixing ring (37), a sealed first chamber (8) is formed between the fixing ring (37), the buffer ring, the first protrusion (6) and the second protrusion (7), a first buffer assembly (9) is provided in the first chamber (8), during blasting, the first buffer assembly (9) provides the buffer ring with a buffer force opposite to the impact force of the blasting on the buffer ring, and the inner ring of the buffer ring is provided with a plurality of water-blocking valves (10); It also comprises a fixing mechanism and a driving mechanism located on the side sealing plate (2), the fixing mechanism comprising a limiting groove (11) arranged on the outer ring surface of the fixing ring (37), an annular cavity (12) being arranged in the pipe (1), a limiting block (13) adapted to the limiting groove (11) being arranged in the annular cavity (12), a first elastic member (14) being arranged between the limiting block (13) and the annular cavity (12), the driving mechanism comprising a driving motor (16) and two directional rotating wheels (15) located in the annular cavity (12), the output end of the driving motor (16) being connected to two free ends of a tensioning cable (17), the tensioning cable (17) being slidably connected to the limiting block (13) in the annular cavity (12) via the two directional rotating wheels (15); The buffer ring comprises a first buffer ring (18) and a second buffer ring (19), the outer ring wall of the second buffer ring (19) is slidably connected to the fixed ring (37), the second protrusion (7) is located on the second buffer ring (19), the water-blocking valve (10) is located on the inner ring of the first buffer ring (18), the inner ring wall of the second buffer ring (19) is provided with a third protrusion (20) slidably connected to the outer ring wall of the first buffer ring (18), the outer ring wall of the first buffer ring (18) is provided with a fourth protrusion (21) slidably connected to the inner ring wall of the second buffer ring (19), and the first buffer ring (18) is provided with a plurality of protrusions (21) slidably connected to the inner ring wall of the second buffer ring (19). A sealed second chamber (22) is formed between the punch ring (18), the second buffer ring (19), the third protrusion (20) and the fourth protrusion (21); a second buffer assembly (23) is arranged in the second chamber (22); during explosion, the second buffer assembly (23) provides the first buffer ring (18) with a buffer force opposite to the impact force generated by the explosion on the first buffer ring (18); an inflatable membrane (24) is arranged on one side of the first buffer ring (1) in the pipeline (1); a cross-shaped notch (25) is arranged at a position of the inflatable membrane (24) corresponding to the inner ring of the second buffer ring (19); The second buffer ring (19) is provided with a through cavity (26), the through cavity (26) is connected with the first cavity (8) and the second cavity (22), and a two-way valve (27) is provided in the through cavity (26); The fixing ring (37) is provided with a first slide groove (28) on the side facing the inside of the pipe (1), the first slide groove (28) is provided with an opening on the side facing the pipe (1), a sliding block (29) is provided in the first slide groove (28) on the side away from the opening of the first slide groove (28), the sliding block (29) penetrates a side wall of the sliding block (29) adjacent to the first chamber (8) and enters the first chamber (8) and is slidably connected with the fixing ring (37), and a second elastic member (39) is provided on the side of the sliding block (29) away from the first chamber (8). 0), a first rotating shaft (31) and a second rotating shaft (32) are provided in the first sliding groove (28), the first rotating shaft (31) and the second rotating shaft (32) are rotatably connected with a first shaft rod (33) and a second shaft rod (34) respectively, one end of the first shaft rod (33) is hinged to the slider (29), one end of the second shaft rod (34) is provided with a second sliding groove (35), the other end of the first shaft rod (33) is slidably connected to the second sliding groove (35) of the second shaft rod (34), and the other end of the second shaft rod (34) is provided with a friction block (36).

2. A pipeline according to claim 1, characterized in that: The first buffer component (9) comprises a first spring connected to the first protrusion (6) and the second protrusion (7) and a first buffer disposed in the first chamber (8); the second buffer component (23) comprises a second spring connected to the third protrusion (20) and the fourth protrusion (21) and a second buffer disposed in the second chamber (22); and the first elastic member (14) and the second elastic member (30) are both springs.

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