A fully enclosed environmentally friendly material guide trough

Abstract

The present invention discloses a fully enclosed environmentally friendly material guide trough, which relates to the field of material guide troughs. A conveying roller frame is installed on the support frame, a conveying belt is arranged on the conveying roller frame, side panels are fixedly connected on both sides of the support frame, an anti-overflow baffle is fixedly connected at the bottom end of the side panel, a fixed plate is fixedly connected along the length direction below the side panel, a rotating plate is rotatably connected at the bottom end of the fixed plate, a tension spring is connected between the inner wall of the rotating plate and the fixed plate, the inner wall of the rotating plate is in close contact with the edge of the conveying belt, a fixed frame is connected between the conveying roller frames, a top roller facing the anti-overflow baffle is arranged in the middle of the fixed frame, and the top roller and the anti-overflow baffle are in close contact with the outer surface and inner surface of the conveying belt respectively. The present invention effectively avoids the generation of gaps between the edge of the conveying belt and the anti-overflow baffle between adjacent conveying roller frames, thereby effectively improving the anti-overflow dust effect at the edge of the material guide trough.

Description

Technical Field

[0001] The invention relates to the field of material guide troughs, in particular to a fully enclosed environmentally friendly material guide trough. Background Art

[0002] Belt conveyor material guide trough is used for conveying various granular, small block, powder and other materials on belt conveyor, and is widely used in mining, metallurgy, coal and other industries.

[0003] In order to reduce the leakage of material dust, the existing material guide trough generally has an anti-overflow baffle in close contact with the conveyor belt on the side of the conveyor belt, a conveying roller frame for supporting the conveyor belt is set at the bottom of the material guide trough, and dust curtains are arranged at intervals along the length direction of the material guide trough. The dust curtains are used to block the smoke and dust generated during material transportation, so that the smoke and dust are settled in the material guide trough, thereby preventing the smoke and dust in the material transportation process from overflowing from the output port of the material guide trough. A buffer bed is generally provided directly below the connection between the material guide trough and the material dropping channel, which plays a buffering role for the falling material, and can effectively reduce the smoke and dust generated by the material hitting the conveyor belt.

[0004] With respect to the above-mentioned related technologies, the conveyor belt between the adjacent conveyor roller frames of the existing material guide trough is easily deformed due to the gravity of the material and the conveyor belt itself. After the edge of the conveyor belt in the area between the conveyor roller frames is deformed, it is easy to produce a gap with the sealing component, resulting in some smoke and dust leakage. In addition, after the existing material falls on the conveyor belt above the buffer bed, the impact force of the falling material is easy to cause the conveyor belt to be depressed downward to a certain extent. The two sides of the conveyor belt of the depressed part are pulled downward and a gap appears between the anti-overflow baffle. In the process of the material impacting the conveyor belt downward and being buffered by the buffer bed, the conveyor belts on both sides of the buffer bed are easily deformed due to being pulled, resulting in smoke and dust leakage. In summary, smoke and dust leakage is easy to occur between the anti-overflow baffle of the existing buffer bed and the conveyor belt due to the deformation of the conveyor belt. Summary of the invention

[0005] Based on this, the purpose of the present invention is to provide a fully enclosed environmentally friendly material guide trough to solve the technical problem that smoke and dust leakage is easily generated between the anti-overflow baffle of the existing buffer bed and the conveyor belt due to the deformation of the conveyor belt.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a fully enclosed environmentally friendly material guide trough, comprising a support frame, a conveying roller frame is installed on the support frame, a conveying belt is arranged on the conveying roller frame, side panels are fixedly connected on both sides of the support frame, anti-overflow baffles are fixedly connected at the bottom ends of the side panels, a fixed plate is fixedly connected along the length direction below the side panels, a rotating plate is rotatably connected at the bottom end of the fixed plate, a tension spring is connected between the inner wall of the rotating plate and the fixed plate, the inner wall of the rotating plate is in close contact with the edge of the conveying belt, a fixed frame is connected between the conveying roller frames, a top roller facing the anti-overflow baffle is arranged in the middle of the fixed frame, and the top roller and the anti-overflow baffle are in close contact with the outer surface and inner surface of the conveying belt respectively.

[0007] By adopting the above technical solution, the rotating plate and the edge of the conveyor belt are kept in full contact, and a top roller structure facing the conveyor belt is provided on the other side of the conveyor belt that contacts the anti-overflow baffle, thereby effectively avoiding the generation of a gap between the edge of the conveyor belt and the anti-overflow baffle between adjacent conveyor roller frames, thereby effectively improving the anti-dust overflow effect at the edge of the material guide trough.

[0008] The present invention is further configured such that the support frame is connected with a buffer bed plate at the feeding position of the material guide trough, the top surface of the buffer bed plate is connected with a buffer plate through a buffer column, the top surface of the buffer plate coincides with the projection surface of the conveyor belt impacted by the material, multiple groups of rotating arms are rotatably connected to both sides of the buffer bed plate, the top end of the rotating arm is rotatably connected with an extrusion roller for extruding the edge portion of the bottom surface of the conveyor belt, and the bottom surface of the buffer plate is connected to a top rod for rotating the rotating arm in the direction of the rotating arm.

[0009] By adopting the above technical solution, the part of the conveyor belt that bears the impact forms an arc structure, which effectively avoids the edge of the conveyor belt from having gaps due to being pulled downward.

[0010] The present invention is further configured such that both ends of the buffer plate are connected to contact rollers, and the top surface of the contact roller is higher than the top surface of the buffer plate.

[0011] By adopting the above technical solution, the friction between the buffer bed and the conveyor belt is effectively reduced, thereby extending the service life of the conveyor belt.

[0012] The present invention is further configured such that the top end of the side panel is fixedly connected to the top panel, the top panel is provided with connecting ports at intervals, a dust curtain is installed in the connecting ports, vents are provided at intervals above the dust curtain, the top end of the connecting port is connected to one end of a connecting pipe, the other end of the connecting pipe is connected to a dust reduction channel, the dust reduction channel passes through the top panel and extends into the bottom of the top panel, and openings arranged along the width direction are spaced apart at the bottom end.

[0013] By adopting the above technical solution, the densely distributed rubber strips in the dust curtain can suppress smoke and dust.

[0014] The present invention is further configured such that a cross-flow fan is provided in the connecting duct, and the blowing direction is toward the connecting port.

[0015] By adopting the above technical solution, the negative pressure in the dust reduction channel enables the smoke and dust in the material guide chute to enter the dust reduction channel more smoothly and finally flow toward the dust barrier curtain.

[0016] The present invention is further configured such that a plurality of air guide channels are connected between the anti-overflow baffle and the fixed plate of the side plate, an axial flow fan is arranged in the air guide channel, and the air blowing direction is toward the inner side of the side plate.

[0017] By adopting the above technical solution, a small amount of smoke and dust overflowing from the gap between the anti-overflow baffle and the conveyor belt returns to the material guide trough through the air guide channel, further improving the sealing performance of the side of the material guide trough.

[0018] The present invention is further configured such that the portion of the air guide passage extending into the inner side of the side plate is bent upward and faces upward.

[0019] By adopting the above technical solution, the part of the air guide channel located inside the material guide trough is arranged to face upward, which can effectively prevent the air outlet of the air guide channel from directly blowing the material in the material guide trough and causing smoke and dust to fly, and can also effectively prevent material particles on the conveyor belt from entering the air guide channel.

[0020] The present invention is further configured such that a sealing rubber film is fixedly connected to the outer surface of the connection between the fixed plate and the rotating plate.

[0021] By adopting the above technical solution, the sealing rubber sheet can improve the sealing performance of the connection between the fixed plate and the rotating plate shaft, and prevent smoke and dust from overflowing along the connection between the fixed plate and the rotating plate shaft.

[0022] The present invention is further configured such that the dust curtain has multiple layers spaced apart along the length direction of the top plate, and each layer of the dust curtain is composed of rubber strips spaced apart along the width direction of the top plate.

[0023] By adopting the above technical solution, the multi-layer dust curtains can directly block the smoke and dust from passing through the inner space of the adjacent material guide troughs, and can also have a good suppressing effect on the smoke and dust in the vertical wind.

[0024] In summary, the present invention mainly has the following beneficial effects:

[0025] 1. The present invention installs a fixed plate at the bottom end of the side plate, and uses a tension spring to pull the rotating plate connected to the edge of the fixed plate so that the rotating plate and the edge of the conveyor belt are in full contact, and a top roller structure facing the conveyor belt is arranged on the other side of the conveyor belt contacting the anti-overflow baffle, which effectively avoids the formation of a gap between the edge of the conveyor belt and the anti-overflow baffle between adjacent conveyor roller frames, thereby effectively improving the anti-overflow dust effect at the edge of the guide trough;

[0026] 2. The present invention connects an air guide channel to the bottom end of the side plate, and utilizes a fan structure provided in the air guide channel to generate negative pressure in the space formed by the anti-overflow baffle, the fixed plate and the rotating plate. A small amount of smoke and dust overflowing through the anti-overflow baffle is transported back to the space inside the side plate through the air guide channel, thereby further improving the anti-overflow dust effect at the edge of the guide trough.

[0027] 3. The present invention arranges a rotating arm structure on both sides of the buffer bed, and uses the squeezing roller connected to the top of the rotating arm to squeeze the outer surface of the conveyor belt. At the moment when the material falls on the conveyor belt and impacts the buffer bed downward, the buffer bed drops in height. After the top rod drives the rotating arm to rotate, the squeezing roller squeezes the intersection of the plane and the inclined surface of the conveyor belt, so that the conveyor belt forms an arc-shaped depression at the moment when it is impacted and depressed. The squeezing roller is used to squeeze the bottom end of the conveyor belt obliquely upward, effectively preventing the conveyor belt at the anti-overflow baffle from being pulled, and further preventing smoke and dust from overflowing from both sides of the conveyor belt.

[0028] 4. The present invention installs a dust reduction channel on the top plate, and uses a connecting pipe to connect the dust reduction channel and the connecting port, so that part of the smoke and dust in the internal space of the material guide trough flows along the dust reduction channel and passes through the connecting pipe, and then flows from top to bottom to the dust curtain. The rubber strips densely distributed in the dust curtain are used to effectively block the smoke and dust, thereby further improving the dust reduction performance of the material guide trough. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A perspective view of the present invention;

[0030] Figure 2 Another perspective perspective diagram of the present invention;

[0031] Figure 3 A three-dimensional diagram of the material guide trough connected to the material drop channel of the present invention;

[0032] Figure 4 For the present invention Figure 3 A magnified view of middle;

[0033] Figure 5 It is a front view of the material guide trough connected to the material drop channel of the present invention;

[0034] Figure 6 For the present invention Figure 5 Enlarged view of middle B;

[0035] Figure 7 It is a side view of the material guide trough connected to the material drop channel of the present invention;

[0036] Figure 8 For the present invention Figure 7 Enlarged view of middle C;

[0037] Fig. 9 A three-dimensional view of the material guide trough connected to the material drop channel after the connecting pipe of the present invention is removed;

[0038] Fig.10 For the present invention Fig. 9 Enlarged view of middle D;

[0039] Fig.11 It is a three-dimensional diagram of the structure of the buffer bed of the present invention;

[0040] Fig.12 It is a three-dimensional diagram of the dust reduction channel of the present invention.

[0041] In the figure: 1. support frame; 2. conveyor roller frame; 3. side plate; 4. top plate; 5. conveyor belt; 6. anti-overflow baffle; 7. fixed plate; 8. rotating plate; 9. tension spring; 10. sealing film; 11. air guide channel; 12. connecting port; 13. connecting pipe; 14. dust reduction channel; 15. dust curtain; 16. fixed frame; 17. fixed column; 18. compression spring; 19. top roller; 20. buffer bed board; 21. buffer plate; 22. buffer column; 23. contact roller; 24. rotating arm; 25. squeezing roller; 26. push rod. DETAILED DESCRIPTION

[0042] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0043] The following describes an embodiment of the present invention based on its overall structure.

[0044] Embodiment 1

[0045] A fully enclosed environmentally friendly material guide trough, such as Figure 1-12As shown, it includes a support frame 1, a conveying roller frame 2 is installed on the support frame 1, a conveying belt 5 is arranged on the conveying roller frame 2, side panels 3 are fixedly connected to both sides of the support frame 1, and the top ends of the side panels 3 on both sides of the support frame 1 are connected with arched top panels 4, which effectively increase the internal volume of the guide trough and are beneficial to the sedimentation of smoke and dust, and the bottom ends of the side panels 3 are fixedly connected with anti-overflow baffles 6, and the lower sides of the side panels 3 are fixedly connected with fixed plates 7 along the length direction. Specifically, the cross-section of the fixed plates 7 is L-shaped and is fixedly connected to the outer wall of the side panels 3. The fixed plates The bottom end of 7 is rotatably connected to a rotating plate 8, and a tension spring 9 is connected between the inner wall of the rotating plate 8 and the fixed plate 7. Specifically, the tension spring 9 is in a state of tightening the rotating plate 8, and is used to apply a pulling force toward the conveyor belt 5 to the lower part of the rotating plate 8. The inner wall of the rotating plate 8 is in close contact with the edge of the conveyor belt 5, and a fixed frame 16 is connected between the conveying roller frames 2. A top roller 19 facing the anti-overflow baffle 6 is arranged in the middle of the fixed frame 16, and the top roller 19 and the anti-overflow baffle 6 are in close contact with the outer surface and inner surface of the conveyor belt 5 respectively.

[0046] See also Figure 3-4 A fixed column 17 is fixedly connected to the fixed frame 16, and a compression spring 18 is sleeved on the outer wall of the fixed column 17. The fixed column 17 is slidably connected to a frame of a top roller 19 along the axial direction. The compression spring 18 is in a compressed state when the top roller 19 contacts the conveyor belt 5. The pressure provided by the compression spring 18 makes the top roller 19 contact the surface of the conveyor belt 5, thereby effectively alleviating the deformation of the conveyor belt between the two sets of conveyor roller frames 2, so that the side of the conveyor belt facing the anti-overflow baffle 6 can be in close contact with the anti-overflow baffle 6 without generating a gap.

[0047] See also Figure 3-8 The side plate 3 is connected with a plurality of air guide channels 11 between the anti-overflow baffle 6 and the fixed plate 7. An axial flow fan is arranged in the air guide channel 11, and the blowing direction is toward the inner side of the side plate 3. The axial flow fan in the air guide channel 11 works to generate negative pressure in the space formed by the anti-overflow baffle 6 and the fixed plate 7. Specifically, the air guide channel 11 is arranged at a position between the two sets of conveying roller frames 2. The conveyor belt 5 here is most likely to have a gap with the anti-overflow baffle 6. A small amount of smoke and dust overflowing from the gap between the anti-overflow baffle 6 and the conveyor belt 5 returns to the material guide trough through the air guide channel 11, further improving the sealing performance of the side of the material guide trough. The part of the air guide channel 11 extending into the inner side of the side plate 3 is bent upward and toward the top, and the part of the air guide channel 11 located inside the material guide trough is arranged toward the top, which effectively avoids the smoke and dust flying caused by the air outlet of the air guide channel 11 directly blowing the material in the material guide trough, and can also effectively prevent the material particles on the conveyor belt 5 from entering the inside of the air guide channel 11.

[0048] See also Figure 7-8A sealing film 10 is fixedly connected to the outer surface of the connection between the fixed plate 7 and the rotating plate 8. Specifically, in order not to affect the normal rotation of the rotating plate 8, both sides of the sealing film 10 are connected to the fixed plate 7 and the rotating plate 8 near the rotating shaft, and a cavity is left at the rotating shaft to prevent the rotating plate 8 from stretching the sealing film 10 when rotating, which can effectively extend the service life of the sealing film 10. The sealing film 10 can improve the sealing performance of the connection between the fixed plate 7 and the rotating plate 8, while ensuring the sealing performance of the connection between the fixed plate 7 and the rotating plate 8, and effectively prevent smoke and dust from overflowing along the connection between the fixed plate 7 and the rotating plate 8.

[0049] Embodiment 2

[0050] A fully enclosed environmentally friendly material guide trough, such as Figure 1-12 As shown, on the basis of embodiment 1, the difference from embodiment 1 is that the support frame 1 is connected with a buffer bed plate 20 at the feeding position of the material guide trough, and the top surface of the buffer bed plate 20 is connected with a buffer plate 21 through a buffer column 22, and the top surface of the buffer plate 21 coincides with the projection surface of the conveyor belt 5 impacted by the material. Specifically, when the material impacts the conveyor belt 5, the buffer plate 21 is pressed down in the vertical direction, and multiple groups of rotating arms 24 are rotatably connected on both sides of the buffer bed plate 20, and the top end of the rotating arm 24 is rotatably connected with a member for squeezing the bottom edge of the conveyor belt 5 Part of the squeezing roller 25, the bottom surface of the buffer plate 21 is connected to the direction of the rotating arm 24 with a push rod 26 for rotating the rotating arm 24. When the material falls on the conveyor belt 5 above the buffer bed, the buffer plate 21 is impacted and drops, and the push rod 26 supports one end of the rotating arm 24 to rotate the rotating arm 24. The squeezing roller 25 connected to the other end of the rotating arm 24 squeezes the edge of the bottom surface of the conveyor belt 5, so that the part of the conveyor belt 5 that bears the impact forms an arc structure, which effectively avoids the edge of the conveyor belt from being pulled downward and causing gaps.

[0051] See also Figure 5-11 Both ends of the buffer plate 21 are connected with contact rollers 23, and the top surface of the contact roller 23 is higher than the top surface of the buffer plate 21. When the conveyor belt 5 above the blanking channel is not impacted by the material, the contact roller 23 above the buffer bed contacts the conveyor belt 5, which effectively reduces the friction between the buffer bed and the conveyor belt 5, thereby extending the service life of the conveyor belt 5. The dust curtain 15 is arranged in multiple layers at intervals along the length direction of the top plate 4, and each layer of the dust curtain 15 is composed of rubber strips arranged at intervals along the width direction of the top plate 4. The multi-layer dust curtain 15 can directly block the smoke and dust from passing through the internal space of the adjacent material guide trough, and can also have a good inhibitory effect on the smoke and dust in the vertical wind. The smoke and dust collide and settle between the dense rubber strips, which can make the dust curtain 15 play the role of filtering dust.

[0052] Embodiment 3

[0053] A fully enclosed environmentally friendly material guide trough, such as Figure 1-12 As shown, on the basis of Example 1, the difference from Example 1 lies in that the top end of the side panel 3 is fixedly connected to the top panel 4, and connecting ports 12 are arranged at intervals on the top panel 4, and a dust curtain 15 is installed in the connecting port 12, and vents are arranged at intervals above the dust curtain 15, and the top end of the connecting port 12 is connected to one end of a connecting pipe 13, and the other end of the connecting pipe 13 is connected to a dust reduction channel 14, and the dust reduction channel 14 extends into the bottom of the top panel 4 after passing through the top panel 4, and is spaced apart at the bottom end with openings arranged along the width direction, and the smoke and dust inside the material guide trough passes through the opening of the dust reduction channel 14, passes through the dust reduction channel 14, and then passes through the connecting pipe 13, and finally flows toward the dust curtain 15 in the vertical direction, and the densely distributed rubber strips in the dust curtain 15 have a suppressive effect on the smoke and dust.

[0054] See also Figure 2-5 Furthermore, in order to make the smoke and dust in the guide trough flow more smoothly into the dust reduction channel 14, a cross-flow fan is arranged in the connecting pipe 13, and the blowing direction is toward the connecting port 12. Specifically, the cross-flow fan is a fan component commonly used in the existing air duct structure, and its detailed structure is not described here. The cross-flow fan in the connecting pipe 13 generates negative pressure in the dust reduction channel 14 when it works. The negative pressure in the dust reduction channel 14 enables the smoke and dust in the guide trough to enter the dust reduction channel 14 more smoothly and finally flow toward the dust barrier curtain 15.

[0055] The working principle of the present invention is as follows: the side of the conveyor belt 5 is in contact with the anti-overflow baffle 6, and the conveyor belt 5 between the two groups of conveyor roller frames 2 sags and deforms due to its own gravity and the gravity of the material, and the top roller 19 between the two groups of conveyor roller frames 2 pushes the deformed conveyor belt 5 toward the anti-overflow baffle 6, effectively avoiding the leakage of smoke and dust generated at the anti-overflow baffle 6, and at the same time, the rotating plate 8 connected to the bottom of the fixed plate 7 is rotated to press the edge of the conveyor belt 5 inward, so that the rotating plate 8 and the conveyor belt 5 are in contact with each other to achieve further sealing. When the conveyor belt 5 is laterally offset and before it is corrected, the tension spring 9 continues to provide tension to the rotating plate 8, so that the rotating plate 8 can stably fit the edge of the conveyor belt 5 when the conveyor belt 5 is offset, effectively avoiding the leakage of smoke and dust from the material guide chute caused by the deformation of the edge of the conveyor belt 5.

[0056] Although an embodiment of the present invention has been shown and described, this specific embodiment is only an explanation of the present invention and is not a limitation of the invention. The specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. After reading this specification, those skilled in the art may make modifications, substitutions and variations to the embodiments without creative contribution as needed without departing from the principles and purpose of the present invention. However, as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A fully enclosed environmentally friendly material guide trough, comprising a support frame (1), a conveying roller frame (2) being mounted on the support frame (1), a conveying belt (5) being arranged on the conveying roller frame (2), side plates (3) being fixedly connected to both sides of the support frame (1), an anti-overflow baffle (6) being fixedly connected to the bottom end of the side plate (3), characterized in that: A fixed plate (7) is fixedly connected to the lower side plate (3) along the length direction, and a rotating plate (8) is rotatably connected to the bottom end of the fixed plate (7). A tension spring (9) is connected between the inner wall of the rotating plate (8) and the fixed plate (7). The inner wall of the rotating plate (8) is in close contact with the edge of the conveyor belt (5). A fixed frame (16) is connected between the conveyor roller frames (2). A top roller (19) facing the anti-overflow baffle (6) is provided in the middle of the fixed frame (16). The top roller (19) and the anti-overflow baffle (6) are in close contact with the outer surface and the inner surface of the conveyor belt (5) respectively. The support frame (1) A buffer bed plate (20) is connected at the feeding position of the material guide trough, and the top surface of the buffer bed plate (20) is connected to a buffer plate (21) via a buffer column (22). The top surface of the buffer plate (21) coincides with the projection surface of the conveyor belt (5) impacted by the material. Two sides of the buffer bed plate (20) are rotatably connected to a plurality of groups of rotating arms (24). The top ends of the rotating arms (24) are rotatably connected to squeezing rollers (25) for squeezing the edge portion of the bottom surface of the conveyor belt (5). The bottom surface of the buffer plate (21) is connected to a push rod (26) for rotating the rotating arm (24) in the direction of the rotating arm (24). The plate (3) is connected with a plurality of air guide channels (11) between the overflow baffle plate (6) and the fixed plate (7), wherein an axial flow fan is arranged in the air guide channel (11), and the blowing direction is toward the inner side of the side plate (3), and the portion of the air guide channel (11) extending into the inner side of the side plate (3) is bent upward and faces upward, and a sealing rubber sheet (10) is fixedly connected to the outer surface of the connection between the fixed plate (7) and the rotating plate (8), and both sides of the sealing rubber sheet (10) are connected to the fixed plate (7) and the rotating plate (8) near the rotating shaft, and a cavity is left at the rotating shaft, and the top of the side plate (3) is fixedly connected to a top A plate (4) is provided with connection ports (12) at intervals on the top plate (4), a dust curtain (15) is installed in the connection port (12), a vent is provided above the dust curtain (15), the top end of the connection port (12) is connected to one end of a connecting pipe (13), the other end of the connecting pipe (13) is connected to a dust reduction channel (14), the dust reduction channel (14) passes through the top plate (4) and extends into the bottom of the top plate (4), and has an opening arranged in the width direction at intervals at the bottom end, a cross-flow fan is provided in the connecting pipe (13), and the blowing direction is toward the connection port (12).

2. The fully enclosed environmentally friendly material guide chute according to claim 1 is characterized in that: Both ends of the buffer plate (21) are connected to contact rollers (23), and the top surface of the contact roller (23) is higher than the top surface of the buffer plate (21).

3. The fully enclosed environmentally friendly material guide chute according to claim 1 is characterized in that: The dust-blocking curtain (15) is arranged in multiple layers at intervals along the length direction of the top plate (4), and each layer of the dust-blocking curtain (15) is composed of rubber strips arranged at intervals along the width direction of the top plate (4).

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