A deep peak shaving feed water preheater for power plants

Abstract

The present invention relates to the technical field of feedwater preheaters, and specifically to a power plant deep peak shaving feedwater preheater, which includes a preheater main body. N baffles are provided on the outside of all heat exchange tubes along the flow direction. The invention also includes a magnet scraping member, a magnet driving member, a push-pull rod and an auxiliary push plate. The magnet scraping member is sleeved outside the heat exchange tube and is used for scraping the outer wall of the heat exchange tube. The magnet driving member moves inside the heat exchange tube to drive the magnet scraping member to move synchronously, so as to realize scraping the outer wall of the heat exchange tube. By applying force to the push-pull rod to drive the magnet driving member to move inside the heat exchange tube, the magnet scraping member sleeved outside the heat exchange tube can be driven to move synchronously, and then the outer wall of the heat exchange tube can be scraped by the scraping pad, so as to improve the cleaning degree of the outer wall of the heat exchange tube, ensure the effective cleaning of the outer wall of the inner heat exchange tube blocked by the outer heat exchange tube, improve the thoroughness of the overall cleaning, and there is no need to disassemble each heat exchange tube for cleaning, which is relatively convenient and labor-saving.

Description

Technical Field

[0001] The present invention relates to the technical field of feed water preheaters, and particularly to a feed water preheater for deep peak shaving in power plants. Background Technique

[0002] Deep peak shaving refers to an operation mode carried out by thermal power plants to adapt to the load changes of the power grid, that is, during the low load period, the power generation output is greatly reduced, so that the output power of the generator is reduced to a very low level to cooperate with the demand changes of the power grid. Deep peak shaving helps to improve the flexibility of the power grid and the utilization rate of renewable energy. The core of thermal power generation is to heat water and generate steam by the heat generated from burning fuel. The steam drives the turbine to rotate, and the turbine is connected to the generator, thereby converting mechanical energy into electrical energy. Among them, in a thermal power plant, a feed water preheater is a device used to preheat the boiler feed water in a thermal power plant. By using the heat at a lower temperature level, the temperature of the feed water is increased, thereby reducing the demand for fuel by the condensed water entering the boiler, achieving the purpose of energy conservation. This not only improves the thermal efficiency of the system, but also reduces fuel consumption and emissions.

[0003] The feed water preheater usually uses the low-pressure steam discharged from the steam turbine or the waste heat of high-temperature flue gas as a heat source to heat water. Since the high-temperature flue gas contains more solid impurities, after the flue gas is introduced into the feed water preheater, the solid impurities in the flue gas will adhere to the heat exchange tubes. After a long time, as the impurities in the high-temperature flue gas become thicker, the heat exchange efficiency will be affected. This makes the feed water preheater need to regularly remove the dust, dirt or other deposits accumulated on the outer wall of the heat exchange tubes. Currently, when cleaning the outer wall of the heat exchange tubes, usually the outer shell of the water preheater is first disassembled, and then high-pressure water is used for flushing or high-pressure gas is used for purging. However, in actual use, since there are usually multiple heat exchange tubes evenly arranged, when using high-pressure water flushing or high-pressure gas purging, most of the outer heat exchange tubes can be cleaned, but the inner heat exchange tubes are blocked by the outer heat exchange tubes, resulting in a large cleaning blind area during the cleaning process, making it difficult to clean them thoroughly. If each heat exchange tube is disassembled for cleaning, it is more troublesome and time-consuming. Therefore, we propose a feed water preheater for deep peak shaving in power plants. Summary of the Invention

[0004] To solve the above technical problems, the embodiment of the present application provides a feed water preheater for deep peak shaving in power plants, including a preheater main body. Both ends of the preheater main body are provided with end covers, and a plurality of heat exchange tubes are evenly arranged inside the preheater main body. N baffle plates are provided outside all the heat exchange tubes along the flow direction, where N is an integer greater than or equal to 1. It further includes:

[0005] A magnet scraping member, which is sleeved outside the heat exchange tube and is used for scraping the outer wall of the heat exchange tube;

[0006] A magnet driving member, the magnet driving member and the magnet scraping member attract each other, and the magnet driving member can be embedded in the heat exchange tube. By moving the magnet driving member in the heat exchange tube, the magnet scraping member is driven to move synchronously to scrape the outer wall of the heat exchange tube.

[0007] A push-pull rod, the push-pull rod is detachably installed on the magnet driving member and is used to apply force to drive the magnet driving member to move.

[0008] In some embodiments, the magnet scraping member includes a magnetic ring sleeved outside the heat exchange tube. Installation rings are fixed at both ends of the magnetic ring. A scraping pad that fits against the outer wall of the heat exchange tube is provided on the side of the installation ring facing the heat exchange tube.

[0009] In some embodiments, N or N + 1 magnet scraping members are provided outside the heat exchange tube.

[0010] In some embodiments, the magnet driving member includes a magnetic column. First convex columns are fixed at both ends of the magnetic column. An embedding groove is axially provided in the first convex column, and a first limiting groove is provided on the inner side wall of the embedding groove.

[0011] In some embodiments, embedding columns that fit into the embedding grooves are fixed at both ends of the push-pull rod, and limiting convex strips that are inserted and matched with the first limiting grooves are fixed on the outer wall of the embedding columns.

[0012] In some embodiments, baffles are installed at both ends inside the preheater main body, and the ends of the heat exchange tube penetrate through the baffles.

[0013] In some embodiments, an auxiliary push plate is further included. A plurality of second convex columns are evenly provided on one side of the auxiliary push plate. A second threaded groove is axially provided in the second convex column, and a second limiting groove is provided on the inner side wall of the second threaded groove.

[0014] In some embodiments, a first threaded groove is provided on the inner wall of the embedding groove.

[0015] In some embodiments, external threads are provided at both ends of the outer wall of the push-pull rod. One end of the push-pull rod is screwed into the first threaded groove through the external thread, and the other end of the push-pull rod is screwed into the second threaded groove through the external thread.

[0016] In some embodiments, grips are installed at both ends of the other side of the auxiliary push plate, and a connecting plate is fixed between the two grips.

[0017] The present invention has at least the following beneficial effects:

[0018] 1. By setting a magnet scraping member, a magnet driving member, and a push-pull rod, the push-pull rod can be detachably installed on the magnet driving member. By applying force through the push-pull rod to drive the magnet driving member to move inside the heat exchange tube, the magnet scraping member sleeved outside the heat exchange tube can be driven to move synchronously, so as to further use the scraping pad to scrape the outer wall of the heat exchange tube, improve the cleanliness of the outer wall of the heat exchange tube, ensure the effective cleaning of the outer wall of the inner heat exchange tube blocked by the outer heat exchange tube, improve the thoroughness of the overall cleaning, and there is no need to disassemble each heat exchange tube for cleaning, which is more convenient and labor-saving.

[0019] 2. Through the setting of the limit convex strip and the first limit groove, while pushing, the push-pull rod can also be rotated to make the magnetic column rotate to drive the magnetic ring to rotate, thereby driving the scraping pad to rotate and scrape, which can further improve the cleaning effect of the outer wall of the heat exchange tube.

[0020] 3. An auxiliary push plate provided with a plurality of second convex columns is configured, which is convenient for the cleaning personnel to apply force, and the outer walls of multiple heat exchange tubes can also be synchronously scraped and cleaned by using the auxiliary push plate, greatly improving the cleaning efficiency.

[0021] 4. The push-pull rod is detachably connected to both the magnet driving member and between the push-pull rod and the auxiliary push plate, which is convenient for assembly and disassembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0023] Figure 2 is a schematic cross-sectional structure diagram of the preheater main body of the present invention;

[0024] Figure 3 is a schematic diagram of the structure of the present invention in a state where the magnet driving member is embedded in the heat exchange tube;

[0025] Figure 4 is a schematic diagram of the structure of the present invention in a state where the magnet scraping member and the magnet driving member are in cooperation;

[0026] Figure 5 is a schematic diagram of the structure of the present invention in a state where the iron scraping member and the magnet driving member are disassembled;

[0027] Figure 6 is a schematic diagram of the structure of the mounting ring of the present invention;

[0028] Figure 7 is a schematic diagram of the structure of the push-pull rod under the first embodiment of the present invention.

[0029] Figure 8 is a schematic diagram of the structure of the push-pull rod under the second embodiment of the present invention;

[0030] Figure 9 is a schematic diagram of the overall structure of the auxiliary push plate of the present invention;

[0031] Figure 10 For the present invention Figure 9 Another structural schematic diagram of an orientation;

[0032] Figure 11 It is a structural schematic diagram of the lower magnet driving member in the second embodiment of the present invention;

[0033] In the figure: 1. Preheater main body; 2. Head; 3. Water inlet pipe; 4. Water outlet pipe; 5. Flue gas inlet pipe; 6. Flue gas outlet pipe; 7. Baffle; 8. Heat exchange pipe; 9. Baffle plate;

[0034] 10. Magnet scraping member; 101. Magnetic ring; 102. Installation ring; 103. Scraping pad;

[0035] 11. Magnet driving member; 111. Magnetic column; 112. First convex column; 113. Embedding groove; 114. First limiting groove; 115. First thread groove;

[0036] 12. Push-pull rod; 13. Embedding column; 14. Limiting convex strip; 15. External thread; 16. Auxiliary push plate; 17. Connecting plate; 18. Grip; 19. Second convex column; 20. Second thread groove; 21. Second limiting groove. Specific embodiments

[0037] 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 of 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.

[0038] Embodiment 1

[0039] Please refer to Figures 1-5, the present invention provides a technical solution: a deep peak shaving feed water preheater for a power plant, including a preheater main body 1. The outer wall of the preheater main body 1 is provided with support frames. Preferably, there are two support frames on the left and right, and the bottom ends of the support frames are provided with installation holes. Bolts can pass through the installation holes to fix the support frames, thereby ensuring the stable installation of the feed water preheater. Both ends of the preheater main body 1 are installed with end heads 2. The end heads 2 are preferably installed through flanges. A water inlet pipe 3 is connected to one of the end heads 2, and a water outlet pipe 4 is connected to the other end head 2. The upper end surface of the preheater main body 1 and near one end of the water inlet pipe 3 is connected with a flue gas inlet pipe 5. The lower end surface of the preheater main body 1 and near one end of the water outlet pipe 4 is connected with a flue gas outlet pipe 6. And a plurality of heat exchange tubes 8 are evenly arranged inside the preheater main body 1. The heat exchange tubes 8 can be arranged in rows at equal distances or distributed in a multi-ring annular array. Baffles 7 are installed at both ends inside the preheater main body 1. The ends of the heat exchange tubes 8 penetrate through the baffles 7. N baffle plates 9 are provided on the outside of all the heat exchange tubes 8 along the flow direction, where N is an integer greater than or equal to 1, which is the prior art. In addition, this deep peak shaving feed water preheater for a power plant further includes a magnet scraping member 10, a magnet driving member 11, and a push-pull rod 12. The magnet scraping member 10 is sleeved outside the heat exchange tube 8 for scraping the outer wall of the heat exchange tube 8. The magnet driving member 11 and the magnet scraping member 10 are attracted to each other by magnetic attraction, and the magnet driving member 11 can be embedded into the heat exchange tube 8. The push-pull rod 12 is detachably installed on the magnet driving member 11. By applying force to the push-pull rod 12, the magnet driving member 11 can be driven to move. The magnet scraping member 10 can be driven to move synchronously by the movement of the magnet driving member 11 inside the heat exchange tube 8 to scrape the outer wall of the heat exchange tube 8, improving the cleaning cleanliness of the outer wall of the heat exchange tube 8, ensuring the effective cleaning of the outer wall of the inner heat exchange tube 8 blocked by the outer heat exchange tube 8, improving the overall cleaning thoroughness, and without the need to disassemble each heat exchange tube 8 for cleaning, which is relatively convenient and time-saving.

[0040] Wherein, N or N + 1 magnet scraping members 10 are provided outside the heat exchange tube 8.

[0041] The number of magnet scraping members 10 outside each heat exchange tube 8 can be described as follows:

[0042] As described above, due to the setting of the baffle plate 9, during the movement of the magnet scraping member 10 outside the heat exchange tube 8, when the magnet scraping member 10 moves to the baffle plate 9, it will be blocked. At this time, another magnet scraping member 10 needs to be provided on the other side of the baffle plate 9. Also, since all the baffle plates 9 have staggered notches up and down, when the notches do not block the magnet scraping member 10, there is no need to provide another magnet scraping member 10 at this time. In short, some heat exchange tubes 8 (at the upper and lower outer peripheries) are provided with magnet scraping members 10 having the same number as the baffle plates 9, and the other heat exchange tubes 8 are provided with magnet scraping members 10 having one more number than the baffle plates 9.

[0043] In summary of the above technical solutions, during specific use, the high-temperature flue gas of a thermal power plant is introduced into the main body 1 of the preheater through the flue gas inlet pipe 5, and the water to be heated is introduced through the water inlet pipe 3. The water to be heated flows through the tube side of the heat exchange tube 8, and the high-temperature flue gas flows through the shell side of the main body 1 of the preheater. Through the guiding action of the baffle plate 9, effective heat exchange can occur between the high-temperature flue gas and the water during the process of the high-temperature flue gas entering from the flue gas inlet pipe 5 and discharging from the flue gas outlet pipe 6, heating the water, reducing the demand for fuel by the condensed water entering the boiler, and achieving the purpose of energy conservation.

[0044] Among them, when more flue gas dust adheres to the outside of the heat exchange tube 8 and affects the heat exchange efficiency, at this time, it is necessary to clean the outer wall of the heat exchange tube 8. During specific cleaning, the staff can first remove the head 2 connected by a flange, then connect the magnet driving member 11 with a push-pull rod 12, and place the magnet driving member 11 into the heat exchange tube 8 to be cleaned. Then, push the push-pull rod 12 to drive the magnet driving member 11 to move in the heat exchange tube 8. When the magnet driving member 11 reaches the position of the magnet scraping member 10, the magnet driving member 11 can drive the magnet scraping member 10 to move synchronously due to the magnetic attraction effect, and then use the magnet scraping member 10 to complete the scraping of the outer wall of the heat exchange tube 8. When the magnet scraping member 10 is blocked by the baffle plate 9, at this time, the magnet driving member 11 can move forward. After the magnet driving member 11 disengages from the original magnet scraping member 10, it can cooperate with the subsequent magnet scraping member 10 as it continues to move to continue using the magnet scraping member 10 to scrape the outer wall of the heat exchange tube 8.

[0045] In the specific implementation manner, refer to Figure 4 and Figure 5 As shown, the magnet scraping member 10 includes a magnetic ring 101 sleeved outside the heat exchange tube 8, and mounting rings 102 are fixed at both ends of the magnetic ring 101. A scraping pad 103 that fits the outer wall of the heat exchange tube 8 is provided on the side of the mounting ring 102 facing the heat exchange tube 8. In the initial state, the magnet scraping member 10 is located at one end, and the inner diameter of the magnetic ring 101 is equal to the outer diameter of the heat exchange tube 8, so that the inner wall of the magnetic ring 101 can move while fitting the outer wall of the heat exchange tube 8.

[0046] Refer to Figure 6 As shown, the above-mentioned scraping pad 103 can be installed on the inner wall of the mounting ring 102 in a detachable manner. Specifically, the scraping pad 103 can be strip-shaped, and the scraping pad 103 and the inner wall of the mounting ring 102 are connected by Velcro. The scraping pad 103 is adhered to the inner wall of the mounting ring 102 in sequence from one end to form a circular ring, and the detachable connection of the scraping pad 103 is convenient for subsequent replacement.

[0047] Refer to Figure 4 and Figure 5As shown, the magnet driving member 11 includes a magnetic column 111. The diameter of the magnetic column 111 is equal to the inner diameter of the heat exchange tube 8. After the magnetic column 111 is embedded in the heat exchange tube 8, the outer wall of the magnetic column 111 can move along the inner wall of the heat exchange tube 8 to ensure the attraction to the magnetic ring 101. First convex columns 112 are fixed at both ends of the magnetic column 111. An embedding groove 113 is axially formed in the first convex column 112, and a first limiting groove 114 is formed in the inner side wall of the embedding groove 113.

[0048] Refer to Figure 7 As shown, fitting columns 13 fitting into the embedding grooves 113 are fixed at both ends of the push-pull rod 12. A limiting convex strip 14 inserted and matched with the first limiting groove 114 is fixed on the outer wall of the fitting column 13.

[0049] Through the above, during actual use, the fitting column 13 at one end of the push-pull rod 12 can be embedded into the embedding groove 113 axially formed in one side of the first convex column 112, and the limiting convex strip 14 can be embedded into the first limiting groove 114. Then, by pushing the magnetic column 111 to move inside the heat exchange tube 8, the magnetic ring 101 can be driven to move. Furthermore, the scraping pad 103 on the mounting ring 102 can be used to scrape the soot. While pushing, the cleaning personnel can also rotate the push-pull rod 12 to rotate the magnetic column 111, so as to drive the magnetic ring 101 to rotate, thereby driving the scraping pad 103 to rotate and scrape, which can further improve the cleaning effect on the outer wall of the heat exchange tube 8. During rotation, since the limiting convex strip 14 is in the first limiting groove 114, it can ensure the synchronous rotation of the push-pull rod 12 and the magnetic column 111.

[0050] Among them, after the magnet driving member 11 is pushed from one end of the heat exchange tube 8 to the other end by using the push-pull rod 12, the push-pull rod 12 can be removed, and then the push-pull rod 12 can be connected to the other end of the magnet driving member 11. Then, the magnet driving member 11 can be pushed from the other side by using the push-pull rod 12. By repeating this several times, the soot deposit on the outer wall of the heat exchange tube 8 can be effectively cleaned, which is relatively convenient.

[0051] Embodiment 2

[0052] Please refer to Figures 8-11 , this embodiment is an extension based on Embodiment 1. Specifically, the power plant deep peak shaving feed water preheater further includes an auxiliary push plate 16. A plurality of second convex columns 19 are evenly arranged on one side of the auxiliary push plate 16. The layout of the plurality of second convex columns 19 is the same as the layout rule between the heat exchange tubes 8. A second threaded groove 20 is axially formed in the second convex column 19, and a second limiting groove 21 is formed in the inner side wall of the second threaded groove 20. Grips 18 are installed at both ends of the other side of the auxiliary push plate 16. A rubber sleeve can be sleeved on the outer wall of the grip 18 to increase the comfort when holding by hand. A connecting plate 17 is fixed between the two grips 18, and screw holes (not shown) can be formed on the mounting plate.

[0053] Refer toFigure 11 As shown, a first thread groove 115 is formed in the inner wall of the slot 113.

[0054] Refer to Figure 8 As shown, external threads 15 are formed at both ends of the outer wall of the push-pull rod 12. One end of the push-pull rod 12 is screwed into the first thread groove 115 through the external thread 15, and the other end of the push-pull rod 12 is screwed into the second thread groove 20 through the external thread 15.

[0055] Through the above, when the push-pull rod 12 is pushed, the end of the push-pull rod 12 away from the magnet driving member 11 can be connected to the second convex post 19 on the auxiliary push plate 16. By using the grip 18 to push the push-pull rod 12, it is convenient for the cleaning personnel to apply force, which is relatively convenient and practical.

[0056] Secondly, one end of the push-pull rod 12 is screwed and connected to the first thread groove 115 in the slot 113 by the external thread 15, and the other end is screwed and connected to the second convex post 19 provided with the second thread groove 20. After the magnet driving member 11 is pushed to the other end at one end in the heat exchange tube 8, there is no need to remove the push-pull rod 12 and then install it from the other side of the magnet driving member 11. At this time, the auxiliary push plate 16 can be directly pulled outwards, which can reduce the disassembly and assembly time to a certain extent and improve the cleaning efficiency.

[0057] In addition, the second convex post 19 on the auxiliary push plate 16 includes the second convex post 19 corresponding to the central heat exchange tube 8 in the preheater main body 1, and also includes the second convex post 19 corresponding to all the heat exchange tubes 8 on one side of the central heat exchange tube 8. When cleaning the outer wall of the heat exchange tube 8, a plurality of push-pull rods 12 can be connected at the same time, so that the magnet driving members 11 are embedded in a plurality of heat exchange tubes 8. At this time, the outer walls of a plurality of heat exchange tubes 8 can be simultaneously scraped and cleaned, which can effectively improve the cleaning efficiency of the outer wall of the heat exchange tube 8. Among them, if it is difficult to push and pull manually, a telescopic member (such as an electric telescopic rod, a cylinder, etc.) can be connected through the connecting plate 17, and the push-pull rod 12 can be pushed by the telescopic member to realize the synchronous cleaning of the outer walls of a plurality of heat exchange tubes 8.

[0058] In addition, it should be noted that: when cleaning the outer walls of a plurality of heat exchange tubes 8 at the same time, rotation cannot be realized during the moving cleaning process; the moving and rotating cleaning can only be realized when cleaning the outer walls of the heat exchange tubes 8 one by one.

[0059] It should be noted that in this text, 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 variation thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device.

[0060] 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 principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A deep peak shaving feed water preheater for a power plant, comprising a preheater main body (1), both ends of the preheater main body (1) are provided with end heads (2), and a plurality of heat exchange tubes (8) are evenly arranged inside the preheater main body (1), and N baffle plates (9) are arranged outside all the heat exchange tubes (8) along the flow direction, N is an integer greater than or equal to 1, and it is characterized in that, It also includes: A magnet scraping member (10) sleeved outside the heat exchange tube (8) for scraping the outer wall of the heat exchange tube (8); A magnet driving member (11) attracted to the magnet scraping member (10), and the magnet driving member (11) can be inserted into the heat exchange tube (8), and the movement of the magnet driving member (11) inside the heat exchange tube (8) drives the magnet scraping member (10) to move synchronously to scrape the outer wall of the heat exchange tube (8); A push-pull rod (12) detachably installed on the magnet driving member (11) for applying force to drive the magnet driving member (11) to move; The magnet scraping member (10) includes a magnetic ring (101) sleeved outside the heat exchange tube (8), and mounting rings (102) are fixed at both ends of the magnetic ring (101). A scraping pad (103) fitting the outer wall of the heat exchange tube (8) is provided on the side of the mounting ring (102) facing the heat exchange tube (8); The magnet driving member (11) includes a magnetic column (111), and first convex columns (112) are fixed at both ends of the magnetic column (111). An embedding groove (113) is axially provided in the first convex column (112), and a first limiting groove (114) is provided on the inner side wall of the embedding groove (left(113); Insertion columns (13) fitting the embedding groove (113) are fixed at both ends of the push-pull rod (12), and limiting convex strips (14) inserted and matched with the first limiting groove (114) are fixed on the outer wall of the insertion column (13).

2. The deep peak shaving feed water preheater for power plants according to claim 1, characterized in that: Baffles (7) are installed at both ends inside the preheater main body (1), and the ends of the heat exchange tube (8) penetrate through the baffles (7).

3. The deep peak shaving feed water preheater for power plants according to claim 1, characterized in that: It also includes an auxiliary push plate (16). A plurality of second convex columns (19) are evenly provided on one side of the auxiliary push plate (16). A second threaded groove (20) is axially provided in the second convex column (19), and a second limiting groove (21) is provided on the inner side wall of the second threaded groove (20).

4. The deep peak shaving feed water preheater for power plants according to claim 3, wherein: A first threaded groove (115) is provided on the inner wall of the embedding groove (113).

5. The deep peak shaving feed water preheater for power plants according to claim 4, characterized in that: External threads (15) are provided at both ends of the outer wall of the push-pull rod (12). One end of the push-pull rod (12) is screwed into the first threaded groove (115) through the external thread (15), and the other end of the push-pull rod (12) is screwed into the second threaded groove (20) through the external thread (15).

6. The deep peak shaving feed water preheater for power plants according to claim 5, characterized in that: Grip handles (18) are installed at both ends of the other side of the auxiliary push plate (16), and a connecting plate (17) is fixed between the two grip handles (18).

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