Filtering and mounting device for gas inlet system of gas turbine

Abstract

The invention discloses a gas turbine air inlet system filtering and mounting device which comprises an air inlet filtering shell, a filtering plate frame is mounted in the air inlet filtering shell, a supporting mechanism and a sealing mechanism are mounted on the outer side of the filtering plate frame, and a positioning and clamping mechanism is arranged on the rear side of the filtering plate frame. A dismounting door is rotationally mounted on the upper surface of the air inlet filtering shell through a hinge, and the inner side of the dismounting door is supported on one side of the filtering plate frame through a supporting damping seat; through the designed supporting mechanism and the sealing mechanism, the filter plate frame is installed in the air inlet filter shell through supporting of the supporting mechanism during use, a gap between the filter plate frame and the air inlet filter shell is sealed through the sealing mechanism, and meanwhile, supporting of the filter plate frame is reinforced through cooperation with the supporting mechanism; and the phenomenon of untight sealing caused by long-term use during use is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of gas turbine air intake systems, and in particular relates to a filter installation device for a gas turbine air intake system. Background Art

[0002] As a highly efficient power plant, the cleanliness of the gas turbine's air intake system is crucial. Filters in the air intake system are used to intercept dust, particulate matter, and other impurities in the air, preventing them from entering the compressor and turbine, where they could cause blade wear, fouling, or even damage. This ensures the safe, efficient, and long-life operation of the gas turbine.

[0003] Currently, gas turbine intake systems generally use filter plates for air filtration. However, traditional technologies have the following shortcomings in terms of filter plate installation and fixation: Complicated assembly and disassembly, low efficiency: Existing technologies often use bolts and other fasteners to secure the filter plates to the filter housing. When replacing or maintaining the filter plates, operators need to enter the narrow filter housing or use specialized tools to remove a large number of bolts. This process is time-consuming and labor-intensive, resulting in low maintenance efficiency and potential safety hazards. Inadequate sealing reliability: The seal between the filter plate and the filter housing is critical to ensuring effective filtration. Traditional installation methods (especially bolted connections) are prone to minor loosening or gaps in the joints during long-term operation due to factors such as airflow pulsation, equipment vibration, and aging of sealing materials, leading to seal failure. Poor sealing allows unfiltered air (bypass) to enter the gas turbine, reducing filtration efficiency and, more seriously, accelerating wear of core components, threatening unit safety. Lack of effective vibration damping: Gas turbine operation and airflow itself generate vibration. Traditional mounting structures lack effective vibration damping and buffering design for the filter plates. The filter plates are directly subjected to vibration shocks for a long time, which may not only aggravate the aforementioned seal failure problem, but may also cause fatigue damage or even fracture of the filter plates themselves or their supporting structures. Therefore, it is necessary to design a gas turbine air intake system filter installation device to solve the above problems. Summary of the Invention

[0004] The object of the present invention is to provide a filter installation device for an air intake system of a gas turbine to solve the problems raised in the above background technology.

[0005] To achieve the above objectives, the present invention provides the following technical solutions: a gas turbine air intake system filter installation device, comprising an air intake filter housing, a filter plate rack installed inside the air intake filter housing, a support mechanism and a sealing mechanism installed on the outside of the filter plate rack, a positioning and locking mechanism provided on the rear side of the filter plate rack, a detachable door rotatably mounted on the upper surface of the air intake filter housing via a hinge, the inner side of the detachable door being supported on one side of the filter plate rack via a support and shock-absorbing seat; The support mechanism includes a rubber support seat fixed to the outer surface of the filter plate frame, a metal rubber seat is provided on the inner bottom of the rubber support seat, a support pressure plate is installed on the surface of the metal rubber seat, and a support air cushion is provided on the outer side of the support pressure plate, and the support air cushion is fixed on the upper side of the rubber support seat; The sealing mechanism includes a sealing seat installed on one side of the rubber support seat, a sealing airbag is opened on the inner side of the sealing seat, a supporting air cavity is opened on the inner side of the supporting air cushion, the supporting air cavity and the sealing airbag are connected by a built-in pipe, the supporting air cavity is connected to an inflation tube through the pipe, and one end of the inflation tube passes through the disassembly and assembly door.

[0006] Preferably, a connecting card seat is provided on one side of the sealing seat, a clamping groove is opened on one side of the rubber support seat, and the connecting card seat is clamped on the inner side of the clamping groove.

[0007] Preferably, the shape of the connecting card seat is set to be T-shaped, and the connecting card seat is engaged in the engaging groove and pressed on one side of the supporting pressure plate and the metal rubber seat.

[0008] Preferably, the positioning and locking mechanism includes a limit support seat welded to the inner wall of the air intake filter housing, a magnetic groove is provided on one side of the limit support seat, a reinforcing rod is installed on the inner side of the magnetic groove, and a locking positioning protrusion is provided on one side of the filter plate frame, the locking positioning protrusion is locked on the inner side of the magnetic groove, and a magnetic protrusion plate is provided on one side of the locking positioning protrusion, and the magnetic protrusion plate is adsorbed on the reinforcing rod.

[0009] Preferably, the filter plate frame comprises an aluminum alloy frame, a honeycomb reinforcement core is installed inside the aluminum alloy frame, and a reinforcement rod is installed inside the honeycomb reinforcement core.

[0010] Preferably, an air guide plate is provided on one side of the filter plate frame, and one end of the reinforcing rod is connected to the air guide plate.

[0011] Preferably, an air intake hood and an air outlet are provided at both ends of the air intake filter housing, an inspection port is provided on the outside of the air intake filter housing, an ash hopper is provided on the lower side of the air intake hood, and a cleaning port is provided on the lower side of the ash hopper.

[0012] Preferably, the supporting shock-absorbing seat includes a mounting seat, a sliding plate is slidably installed inside the mounting seat, an auxiliary shock-absorbing seat and a damping spring are provided on one side of the sliding plate, a sliding column and a limit spring are provided on the other side of the sliding plate, the sliding column is slidably installed on the mounting seat, a limit seat is provided at one end of the sliding column, and the limit seat is pressed on the filter plate frame.

[0013] Preferably, a mounting base is fixedly mounted on the outer side of the damping spring, a damping slide is fixedly mounted on one side of the mounting base, and the damping slide is tightly attached to the inner wall of the mounting base.

[0014] Preferably, the auxiliary shock-absorbing seat includes a fixed column installed on the mounting seat and a sliding cylinder installed on the sliding plate, an auxiliary spring is installed inside the sliding cylinder, and an auxiliary pressure plate is fixedly installed at one end of the fixed column, and the auxiliary pressure plate is slidably installed in the sliding cylinder and pressed on the auxiliary spring.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. Through the designed support mechanism and sealing mechanism, the filter plate holder is installed inside the air intake filter housing through the support of the support mechanism during use, and the gap between the filter plate holder and the air intake filter housing is sealed through the sealing mechanism. At the same time, the support for the filter plate holder is strengthened with the support mechanism, thereby reducing the phenomenon of loose sealing due to long-term use during use.

[0016] 2. Through the designed disassembly and assembly door and positioning clamping mechanism, the filter plate frame can be disassembled and assembled through the disassembly and assembly door during use, and the positioning clamping mechanism can be used for positioning without disassembling bolts, which is more convenient. The support of the supporting mechanism and the sealing mechanism ensures that the installation and use are more convenient.

[0017] 3. Through the designed support shock-absorbing seat, the filter plate holder is pushed by the damping spring and the limit spring to ensure that it is convenient to limit the position when it is installed on the positioning clamping mechanism during use, and the elastic force of the damping spring and the limit spring, the support mechanism and the sealing mechanism are used for buffering and shock absorption, thereby ensuring that the filter plate holder is more stable during use and reducing damage due to vibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 This is a schematic diagram of the inner structure of the present invention; Figure 3 It is a schematic diagram of the installation structure of the present invention; Figure 4 This is a schematic diagram of the supporting sealing structure of the present invention; Figure 5 This is a schematic diagram of the supporting shock-absorbing seat structure of the present invention; Figure 6 This is a schematic diagram of the supporting shock-absorbing seat structure of the present invention; Figure 7 This is a schematic structural diagram of the auxiliary shock-absorbing seat of the present invention; Figure: 1, air intake filter housing; 11, air intake cover; 12, air outlet; 13, inspection port; 14, disassembly door; 15, ash hopper; 16, cleaning port; 17, filter plate holder; 171, aluminum alloy frame; 172, honeycomb reinforcement core; 18, air guide plate; 2. Support mechanism; 21. Rubber support seat; 22. Metal rubber seat; 23. Support pressure plate; 24. Support air cushion; 25. Support air cavity; 26. Clamping groove; 3. Sealing mechanism; 31. Sealing seat; 32. Sealing airbag; 33. Connecting card seat; 34. Inflating tube; 4. Positioning clamping mechanism; 41. Limiting support seat; 42. Clamping positioning protrusion; 43. Magnetic suction groove; 44. Reinforcing rod; 45. Magnetic suction protrusion; 5. Support shock-absorbing seat; 51. Mounting seat; 52. Sliding plate; 53. Sliding column; 54. Limiting seat; 55. Limiting spring; 56. Damping spring; 57. Mounting card seat; 58. Damping slide; 6. Auxiliary shock-absorbing seat; 61. Sliding cylinder; 62. Fixed column; 63. Auxiliary pressure plate; 64. Auxiliary spring. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0020] Example 1: Please refer to Figures 1 to 7 The present invention provides a technical solution: a gas turbine intake system filter installation device, comprising an intake filter housing 1, a filter plate frame 17 installed inside the intake filter housing 1, a support mechanism 2 and a sealing mechanism 3 installed on the outside of the filter plate frame 17, a positioning and locking mechanism 4 provided on the rear side of the filter plate frame 17, a disassembly door 14 rotatably installed on the upper surface of the intake filter housing 1 via a hinge, and the inner side of the disassembly door 14 is supported on one side of the filter plate frame 17 via a support and shock-absorbing seat 5; The supporting mechanism 2 includes a rubber supporting seat 21 fixed to the outer surface of the filter plate frame 17, a metal rubber seat 22 is provided at the inner bottom of the rubber supporting seat 21, a supporting pressure plate 23 is installed on the surface of the metal rubber seat 22, and a supporting air cushion 24 is provided on the outer side of the supporting pressure plate 23. The supporting air cushion 24 is fixed to the upper side of the rubber supporting seat 21, and the supporting capacity is enhanced by the metal rubber seat 22 and the supporting air cushion 24. The vibration generated when the filter plate frame 17 is filtering can be supported and buffered by the metal rubber seat 22, the supporting air cushion 24 and the sealing mechanism 3; the sealing mechanism 3 includes a sealing seat 31 installed on one side of the rubber supporting seat 21, a sealing air bag 32 is provided on the inner side of the sealing seat 31, and a supporting air cavity 25 is provided on the inner side of the supporting air cushion 24. There is a support between the supporting air cavity 25 and the sealing air bag 32. The built-in pipeline is connected, and the supporting air cavity 25 is connected to the inflation tube 34 through the pipeline, and one end of the inflation tube 34 passes through the disassembly and assembly door 14. When in use, the supporting air cavity 25 and the sealing airbag 32 are ventilated through the inflation tube 34, so that the sealing seat 31 and the supporting air cushion 24 bulge and support on the inner wall of the air intake filter housing 1; a connecting clamping seat 33 is provided on one side of the sealing seat 31, and a clamping groove 26 is opened on one side of the rubber support seat 21. The connecting clamping seat 33 is clamped on the inner side of the clamping groove 26, which facilitates the connection between the rubber support seat 21 and the sealing seat 31 when in use; the shape of the connecting clamping seat 33 is set to be T-shaped, and the connecting clamping seat 33 is clamped in the clamping groove 26 and pressed on one side of the supporting pressure plate 23 and the metal rubber seat 22, ensuring that the connection between the connecting clamping seat 33 and the metal rubber seat 22 is more stable when in use.

[0021] Further, see Figures 1 to 7 The filter plate frame 17 includes an aluminum alloy frame 171, and a honeycomb reinforcement core 172 is installed inside the aluminum alloy frame 171. The inner side of the honeycomb reinforcement core 172 is installed with a reinforcement rod 44. When in use, the strength and anti-support capacity of the frame are strengthened by the aluminum alloy frame 171 and the honeycomb reinforcement core 172; an air guide plate 18 is provided on one side of the filter plate frame 17, and one end of the reinforcement rod 44 is connected to the air guide plate 18. When in use, the filter plate frame 17 can be strengthened by the reinforcement rod 44. The electrostatic generator and the air guide plate 18 can be connected to the reinforcement rod 44 as needed to cooperate with the auxiliary adsorption and filtration of dust in the air; an air intake cover 11 and an air outlet 12 are provided at both ends of the air intake filter housing 1, and an inspection port 13 is provided on the outside of the air intake filter housing 1, and an ash hopper 15 is provided on the lower side of the air intake cover 11. A cleaning port 16 is provided on the lower side of the ash hopper 15, which is convenient for collecting and cleaning impurities such as dust filtered out when in use.

[0022] From the above description, it can be seen that the present invention has the following beneficial effects: when in use, the filter plate frame 17 is installed inside the air intake filter housing 1 through the support of the support mechanism 2, and the gap between the filter plate frame 17 and the air intake filter housing 1 is sealed by the sealing mechanism 3. At the same time, the support for the filter plate frame 17 is strengthened in conjunction with the support mechanism 2, thereby reducing the phenomenon of loose sealing due to long-term use during use.

[0023] Example 2: Please refer to Figures 1 to 7 As shown, based on the first embodiment, the present invention provides a technical solution: the positioning and locking mechanism 4 includes a limiting support seat 41 welded to the inner wall of the air intake filter housing 1, and a magnetic suction groove 43 is provided on one side of the limiting support seat 41, and a reinforcing rod 44 is installed on the inner side of the magnetic suction groove 43. A locking positioning protrusion 42 is provided on one side of the filter plate rack 17, and the locking positioning protrusion 42 is locked in the inner side of the magnetic suction groove 43, and a magnetic convex plate 45 is provided on one side of the locking positioning protrusion 42. The magnetic convex plate 45 is adsorbed on the reinforcing rod 44, and the filter plate rack 17 is installed in the air intake filter housing 1 through the position of the disassembly door 14. The position of the limiting support seat 41 and the locking positioning protrusion 42 correspond to each other, and the magnetic suction groove 43 and the reinforcing rod 44 are locked and adsorbed on the locking positioning protrusion 42 and the magnetic convex plate 45, thereby facilitating positioning and disassembly.

[0024] The disassembly and assembly door 14 and the positioning locking mechanism 4 of the above-mentioned technical solution are adopted. When in use, the filter plate frame 17 is disassembled and assembled through the disassembly and assembly door 14, and the locking and positioning of the positioning locking mechanism 4 does not require the disassembly and assembly of bolts, which is more convenient. The support of the supporting mechanism 2 and the sealing mechanism 3 ensures that the installation and use are more convenient.

[0025] Further, see Figures 1 to 7, the supporting shock-absorbing seat 5 includes a mounting seat 51, a sliding plate 52 is slidably installed inside the mounting seat 51, an auxiliary shock-absorbing seat 6 and a damping spring 56 are provided on one side of the sliding plate 52, and a sliding column 53 and a limit spring 55 are provided on the other side of the sliding plate 52. The sliding column 53 is slidably installed on the mounting seat 51, and a limit seat 54 is provided at one end of the sliding column 53. The limit seat 54 is pressed on the filter plate frame 17. When in use, the limit seat 54 drives the sliding column 53 to slide, and drives the sliding plate 52 to press on the damping spring 56 and the limit spring 55 for buffering; a mounting bracket 57 is fixedly installed on the outside of the damping spring 56, and a damping slide 58 is fixedly installed on one side of the mounting bracket 57. The damping slide 58 is tightly It is attached to the inner wall of the mounting seat 51. When in use, the damping spring 56 drives the mounting seat 57 and the damping slide 58 to slide when it is forced to expand and contract, and the sliding friction between the damping slide 58 and the mounting seat 51 provides damping for shock absorption; the auxiliary shock-absorbing seat 6 includes a fixed column 62 mounted on the mounting seat 51 and a sliding cylinder 61 mounted on the sliding plate 52. An auxiliary spring 64 is installed inside the sliding cylinder 61, and an auxiliary pressure plate 63 is fixedly installed at one end of the fixed column 62. The auxiliary pressure plate 63 is slidingly installed in the sliding cylinder 61 and pressed on the auxiliary spring 64. When the sliding plate 52 slides, it drives the sliding cylinder 61 to move, so that the auxiliary pressure plate 63 at one end of the fixed column 62 is pressed on the auxiliary spring 64 to assist in buffering and damping.

[0026] The support shock-absorbing seat 5 using the above-mentioned technical solution ensures that the filter plate holder 17 is conveniently limited when installed on the positioning and locking mechanism 4 through the push of the damping spring 56 and the limit spring 55 during use, and buffers and reduces shock through the elastic force of the damping spring 56 and the limit spring 55, the support mechanism 2 and the sealing mechanism 3, thereby ensuring that the filter plate holder 17 is more stable during use and reducing damage due to vibration.

[0027] The working principle and use process of the present invention are as follows: during installation and use, the filter plate frame 17 is installed in the air intake filter housing 1 through the position of the disassembly and assembly door 14, and the position of the limit support seat 41 and the engaging positioning protrusion 42 are aligned, and the magnetic groove 43 and the reinforcing rod 44 are engaged and adsorbed on the engaging positioning protrusion 42 and the magnetic protrusion plate 45, so as to facilitate positioning and installation, and during installation, the support is assisted by the support mechanism 2 and the sealing mechanism 3, and then the disassembly and assembly door 14 is covered on the air intake filter housing 1 and fixed by bolts, and at the same time, the limit seat 54 is supported on the filter plate frame 17 for upper limit installation, and the supporting air cavity 25 and the sealing air bag 32 are ventilated through the inflation tube 34, so that the sealing seat 31 and the supporting air cushion 24 bulge and support on the inner wall of the air intake filter housing 1, and then the filter plate frame 17 is installed. While sealing, the metal rubber seat 22 and the supporting air cushion 24 are used to strengthen the supporting capacity. The vibration generated when the filter plate frame 17 is filtering can be supported and buffered by the metal rubber seat 22, the supporting air cushion 24 and the sealing seat 31, and when the filter plate frame 17 is subjected to force, the elastic force of the damping spring 56 and the auxiliary spring 64 pushes the sliding column 53 and the limit seat 54 to be pressed tightly against the filter plate frame 17 for buffering and shock absorption, and the damping slide seat 58 slides frictionally in the mounting seat 51 to further provide damping and shock absorption, and cooperates with the support of the support mechanism 2 and the sealing mechanism 3 to reduce the damage of the filter plate frame 17, and the slight vibration of the filter plate frame 17 can shake the dust down to clean it and reduce blockage, and the dust and the like are collected through the ash hopper 15 and cleaned through the cleaning port 16.

[0028] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are 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 explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0029] The above description is only used to illustrate the technical solution of the present invention and is not intended to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in this field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A gas turbine air intake system filter installation device, comprising an air intake filter housing (1), characterized in that: A filter plate frame (17) is installed inside the air intake filter housing (1), a support mechanism (2) and a sealing mechanism (3) are installed on the outside of the filter plate frame (17), a positioning and locking mechanism (4) is provided on the rear side of the filter plate frame (17), and a disassembly door (14) is installed on the upper surface of the air intake filter housing (1) by rotating through a hinge, and the inner side of the disassembly door (14) is supported on one side of the filter plate frame (17) through a support shock-absorbing seat (5); The support mechanism (2) comprises a rubber support seat (21) fixed to the outer surface of the filter plate frame (17); a metal rubber seat (22) is provided at the inner bottom of the rubber support seat (21); a support pressure plate (23) is installed on the surface of the metal rubber seat (22); a support air cushion (24) is provided on the outer side of the support pressure plate (23); and the support air cushion (24) is fixed on the upper side of the rubber support seat (21); The sealing mechanism (3) comprises a sealing seat (31) mounted on one side of the rubber support seat (21), a sealing airbag (32) is provided on the inner side of the sealing seat (31), a supporting air cavity (25) is provided on the inner side of the supporting air cushion (24), the supporting air cavity (25) and the sealing airbag (32) are connected via a built-in pipe, the supporting air cavity (25) is connected to an inflation tube (34) via the pipe, and one end of the inflation tube (34) passes through the disassembly door (14).

2. A gas turbine air intake system filter installation device according to claim 1, characterized in that: A connecting clamping seat (33) is provided on one side of the sealing seat (31), a clamping groove (26) is provided on one side of the rubber support seat (21), and the connecting clamping seat (33) is clamped on the inner side of the clamping groove (26).

3. A gas turbine air intake system filter installation device according to claim 2, characterized in that: The shape of the connecting card seat (33) is set to be T-shaped. The connecting card seat (33) is engaged in the engaging groove (26) and pressed against one side of the supporting pressure plate (23) and the metal rubber seat (22).

4. The gas turbine air intake system filter installation device according to claim 1, characterized in that: The positioning and locking mechanism (4) includes a limiting support seat (41) welded to the inner wall of the air intake filter housing (1), a magnetic groove (43) is provided on one side of the limiting support seat (41), a reinforcing rod (44) is installed on the inner side of the magnetic groove (43), and a locking positioning protrusion (42) is provided on one side of the filter plate frame (17), the locking positioning protrusion (42) is locked on the inner side of the magnetic groove (43), and a magnetic convex plate (45) is provided on one side of the locking positioning protrusion (42), and the magnetic convex plate (45) is adsorbed on the reinforcing rod (44).

5. The gas turbine air intake system filter installation device according to claim 1, characterized in that: The filter plate frame (17) comprises an aluminum alloy frame (171), a honeycomb reinforcement core (172) is installed inside the aluminum alloy frame (171), and a reinforcement rod (44) is installed inside the honeycomb reinforcement core (172).

6. A gas turbine air intake system filter installation device according to claim 5, characterized in that: An air guide plate (18) is provided on one side of the filter plate frame (17), and one end of the reinforcing rod (44) is connected to the air guide plate (18).

7. The gas turbine air intake system filter installation device according to claim 1, characterized in that: An air intake hood (11) and an air outlet (12) are provided at both ends of the air intake filter housing (1), an inspection port (13) is provided on the outside of the air intake filter housing (1), an ash hopper (15) is provided on the lower side of the air intake hood (11), and a cleaning port (16) is provided on the lower side of the ash hopper (15).

8. The gas turbine air intake system filter installation device according to claim 1, characterized in that: The supporting shock-absorbing seat (5) includes a mounting seat (51), a sliding plate (52) is slidably mounted inside the mounting seat (51), an auxiliary shock-absorbing seat (6) and a damping spring (56) are provided on one side of the sliding plate (52), and a sliding column (53) and a limit spring (55) are provided on the other side of the sliding plate (52), the sliding column (53) is slidably mounted on the mounting seat (51), and a limit seat (54) is provided at one end of the sliding column (53), and the limit seat (54) is pressed on the filter plate frame (17).

9. A gas turbine air intake system filter installation device according to claim 8, characterized in that: A mounting base (57) is fixedly mounted on the outer side of the damping spring (56), a damping slide (58) is fixedly mounted on one side of the mounting base (57), and the damping slide (58) is tightly attached to the inner wall of the mounting base (51).

10. The gas turbine air intake system filter installation device according to claim 8, characterized in that: The auxiliary shock-absorbing seat (6) comprises a fixed column (62) mounted on the mounting seat (51) and a sliding cylinder (61) mounted on the sliding plate (52), an auxiliary spring (64) being mounted inside the sliding cylinder (61), an auxiliary pressure plate (63) being fixedly mounted on one end of the fixed column (62), and the auxiliary pressure plate (63) being slidably mounted in the sliding cylinder (61) and pressed on the auxiliary spring (64).

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