Multi-stage sewage treatment equipment

Abstract

The invention relates to the technical field of sewage treatment equipment, and discloses a multi-stage sewage treatment device which comprises a settling tank, an overflow port is formed in the upper portion of one side of the settling tank, a sewage inlet pipe is connected to the lower portion of the side edge of the settling tank below the overflow port, and a sewage outlet is formed in the side, away from the sewage inlet pipe, of the bottom of the settling tank. The drain outlet is connected with a drain pipe; a first filter disc is arranged at the position, close to the center, in the settling tank, a through hole is formed in the middle of the first filter disc, an outer cylinder is arranged at the through hole, an overflow drainage plate is arranged at the top of the outer cylinder, a rotating disc is arranged in the middle of the overflow drainage plate, a flow guide drainage plate is arranged at the top of the rotating disc, and a rotating shaft is arranged at the center of the top of the flow guide drainage plate; the top of the rotating shaft penetrates through the settling tank and is connected with a driver mounted in the center of the outer top wall of the settling tank, so that the liquid level of sewage is prevented from continuously rising, light impurities overflowing along with the sewage can be intercepted, and the sewage treatment effect is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment equipment, and in particular to a multi-stage sewage treatment equipment. Background Art

[0002] Papermaking equipment will produce wastewater containing cellulose, lignin, fillers, chemical additives and other pollutants in the papermaking process. At present, the equipment for physical treatment of papermaking wastewater mainly includes sedimentation towers, flotation machines, flotation towers, etc. Take the treatment process of sedimentation towers as an example: in the process of sewage treatment, the sewage is first discharged into the sedimentation tower. The heavier debris in the sewage will fall to the bottom of the sedimentation tower after a period of time, and the lighter debris in the sewage will float on the liquid surface of the sewage. When the liquid level of the sewage is above the overflow port on the upper side of the sedimentation tower, it will be discharged through the overflow port. This will reduce the effect of sewage treatment.

[0003] In the prior art, a filter is set at the overflow port for interception. However, with the discharge of sewage, the light debris intercepted by the filter at that location will increase, and the filter at that location will eventually be blocked. The blockage will affect the discharge of sewage at the overflow port, causing the sewage level in the sedimentation tower to continue to rise. When the sewage level in the sedimentation tower is not at the height intercepted by the filter, the sewage in the sedimentation tower will directly pass through the filter and flow out through the overflow port, causing part of the sewage to be discharged without being filtered, thereby reducing the effect of sewage treatment. Summary of the invention

[0004] The technical task of the present invention is to provide a multi-stage sewage treatment equipment to solve the above problems.

[0005] The technical solution of the present invention is achieved in this way: A multi-stage sewage treatment equipment comprises a sedimentation tank, wherein an overflow port is provided at the upper part of one side of the sedimentation tank, a sewage inlet pipe is connected to the lower part of the side of the sedimentation tank below the overflow port, a sewage outlet is provided at the bottom of the sedimentation tank away from the sewage inlet pipe, and the sewage outlet is connected to the sewage outlet; a first filter disc is provided near the center of the sedimentation tank, a through hole is provided in the middle of the first filter disc, an outer cylinder is provided at the through hole, an overflow guide plate is provided at the top of the outer cylinder, a rotating disc is provided in the middle of the overflow guide plate, a guide guide plate is provided at the top of the rotating disc, and a There is a rotating shaft, the top of which passes through the sedimentation tank and is connected to a driver installed at the center of the outer top wall of the sedimentation tank; a sedimentation tank is provided at the bottom of the sedimentation tank, a boss is provided at the center of the sedimentation tank, a number of flow-driving plates are evenly arranged on the top side of the boss, a rotating column three is provided at the top center of the boss, a second filter disc is provided at the top of the rotating column three, a rotating column two is provided at the top center of the second filter disc, the rotating column two passes through the through hole, a rotating column one is provided on the top of the rotating column two, and the top of the rotating column one is fixed at the bottom center of the turntable.

[0006] Preferably, a grid is provided between the turntable and the inner wall of the through hole, and the grid is formed by weaving an elastic material; the guide drainage plate extends outward to form a conical structure; the overflow drainage plate is arranged as a plurality of folded structures, and the overflow drainage plate extends inward to form an inverted cone-shaped structure formed by a depression inside.

[0007] Preferably, a plurality of support rods are provided on the outer side and the inner side of the bottom of the overflow guide plate, and the bottoms of the support rods are respectively fixed on the top of the first filter disc.

[0008] Preferably, an overflow return plate is provided on the top of the second filter disc, and the bottom of the second rotating column is fixed at the center of the overflow return plate.

[0009] Preferably, the overflow drainage plate is provided with a plurality of filter holes, the bottom periphery of the turntable is provided with an inner cylinder, the outer wall of the inner cylinder is provided with an activated carbon filter, the inner wall of the outer cylinder is provided with an adsorption net, and the adsorption net is provided with an adsorbent.

[0010] Preferably, the inner wall of the sedimentation tank is provided with a slide groove, the inner wall of the slide groove is provided with an inner filter plate, a heavy debris sedimentation groove is provided between the inner wall of the inner filter plate and the side of the boss, a guide groove is left between any adjacent flow-displacing plates, and an arc-shaped baffle is provided on the top of the boss close to the upper side of the guide groove.

[0011] Preferably, a disc is sleeved on the upper part of the rotating column, a plurality of upper connecting frames are provided on the side of the disc, a column is provided at the other end of the upper connecting frame, a support rod is provided at the bottom center of the column, a scraper is provided at the bottom of the support rod, a lower connecting frame is connected to the outer side of the column, and a limiting wheel matching the slide groove is provided at one end of the lower connecting frame away from the column.

[0012] Preferably, the sewage outlet is located at the heavy debris sedimentation tank; the column is a cavity column, a condenser is provided inside the column, the upper connecting frame, the lower connecting frame and the support rod are all conduits, and the upper connecting frame, the lower connecting frame and the support rod are respectively connected to the inside of the column, the scraper and the limiting wheel.

[0013] Compared with the prior art, the advantages and positive effects of the present invention are: 1. The equipment introduces sewage into the sedimentation tank, and when the sewage passes through the second filter plate and the first filter screen, the light debris contained in the sewage will go up with the sewage, and will be filtered again through the filter holes on the overflow drainage plate. After some light debris rushes through the filter holes or meshes, the light debris is intercepted by the cooperation of the guide drainage plate and the overflow drainage plate with the rotational movement of the rotating shaft. The light debris constantly hits the guide drainage plate and the overflow drainage plate under the action of the rotational movement. The folding structure of the overflow drainage plate introduces the light debris that hits to the middle bottom, so as to prevent the light debris from flowing out from the overflow port on the upper side of the sedimentation tank with the sewage, prevent the sewage level from continuing to rise, and intercept the light debris overflowing with the sewage, thereby improving the sewage treatment effect.

[0014] 2. After the heavy debris in the sewage enters the sedimentation tank together with the sewage, the second filter disc rotates to generate a rotational motion. The flow rate of the heavy debris will increase during the rotational motion. The heavy debris will be thrown around and hit the inner wall while flowing. The thrown heavy debris will flow into the heavy debris sedimentation tank along the convex surface. Under the action of the scraper, the precipitated heavy debris will be scraped off to the sewage outlet. In this way, the sedimentation time of the heavy debris is greatly shortened, which plays a certain guiding role in rapid discharge.

[0015] 3. The light debris entering from the upper part of the sedimentation tank hits the overflow drainage plate below under the rotation of the guide drainage plate, and is concentrated in the middle through the folding structure of the overflow drainage plate, thereby changing the flow direction of the light debris, gathering the light debris to the grid far from the overflow port, and entering the cavity formed between the inner cylinder and the outer cylinder through the holes in the grid. Then, through the rotational motion of the inner cylinder, a vortex rotation force is formed inside, and the light debris entering will roll under this motion. When the second filter disc rotates, it will bring the light debris above downward, and a part of the light debris will be adsorbed by the adsorption net on the inner wall of the outer cylinder, and after adsorption, it will be filtered by the activated carbon filter on the outer wall of the inner cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 is a schematic diagram of the overall structure according to an embodiment of the present invention; Figure 2 is a schematic diagram of the structure of the connection end between the first filter disc and the second filter disc according to an embodiment of the present invention; Figure 3 is a schematic diagram of the structure of a first filter disc end according to an embodiment of the present invention; Figure 4 2 is a schematic diagram of the structure of the connection end of the overflow guide plate according to an embodiment of the present invention; Figure 5 is a top view of an overflow guide plate according to an embodiment of the present invention; Figure 6 is a schematic diagram of the structure of a turntable end according to an embodiment of the present invention; Figure 7 is a schematic diagram of the structure of the connection end between the second filter disc and the sedimentation tank according to an embodiment of the present invention; Figure 8 Schematic diagram of the sedimentation tank end structure according to an embodiment of the present invention.

[0018] In the figure: 1. Sedimentation tank; 2. Overflow port; 3. Sewage inlet pipe; 4. Sewage outlet; 5. Sewage outlet pipe; 6. First filter disc; 7. Through hole; 8. Outer cylinder; 9. Overflow guide plate; 10. Turntable; 11. Guide guide plate; 12. Rotating shaft; 13. Driver; 14. Sedimentation tank; 15. Boss; 16. Drive plate; 17. Rotating column three; 18. Second filter disc; 19. Rotating column two; 20. Rotating column one; 21. Grid; 22. Support rod; 23. Overflow return plate; 24. Inner cylinder; 25. Slide; 26. Inner filter plate; 27. Arc baffle; 28. Disc; 29. ​​Upper connecting frame; 30. Column; 31. Support rod; 32. Scraper; 33. Lower connecting frame; 34. Limiting wheel; 35. Heavy debris sedimentation tank; 36. Guide trough. DETAILED DESCRIPTION

[0019] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0020] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0021] According to an embodiment of the present invention, Figure 1-Figure 8 Shown in: The present invention provides a multi-stage sewage treatment equipment, including a sedimentation tank 1, an overflow port 2 is provided at the upper part of one side of the sedimentation tank 1, a sewage inlet pipe 3 is connected to the lower part of the side of the sedimentation tank 1 below the overflow port 2, a sewage outlet 4 is provided at the bottom of the sedimentation tank 1 away from the sewage inlet pipe 3, and a sewage outlet 5 is connected to the sewage outlet 4; a first filter disc 6 is provided near the center of the sedimentation tank 1, a through hole 7 is provided in the middle of the first filter disc 6, an outer cylinder 8 is provided at the through hole 7, an overflow guide plate 9 is provided at the top of the outer cylinder 8, a rotating disc 10 is provided in the middle of the overflow guide plate 9, a guide guide plate 11 is provided at the top of the rotating disc 10, and a rotating shaft 1 is provided at the center of the top of the guide guide plate 11 2. The top of the rotating shaft 12 passes through the sedimentation tank 1 and is connected to the driver 13 installed at the center of the outer top wall of the sedimentation tank 1; a sedimentation tank 1 is provided at the bottom, a boss 15 is provided at the center of the sedimentation tank 14, and a plurality of flow-driving plates 16 are evenly arranged on the top side of the boss 15, a rotating column three 17 is provided at the center of the top of the boss 15, a second filter disc 18 is provided at the top of the rotating column three 17, a rotating column two 19 is provided at the center of the top of the second filter disc 18, the rotating column two 19 passes through the through hole 7, a rotating column one 20 is provided at the top of the rotating column two 19, and the top of the rotating column one 20 is fixed at the bottom center of the turntable 10.

[0022] The sedimentation tank 14 in this solution is embedded from the bottom of the sedimentation tank 1, that is, the sedimentation tank 14 is a detachable structure, the bottom of the rotating column 3 17 is in contact with the top center end of the boss 15, and the boss 15 remains stationary during the rotation of the rotating column 3 17. When the sedimentation tank 14 needs to be subsequently cleaned or repaired, it is only necessary to pull the sedimentation tank 14 out of the sedimentation tank 1. At the same time, an inspection door can be set at the upper part of the sedimentation tank 1 to facilitate cleaning and maintenance of the internal structure.

[0023] Among them, a grid 21 is provided between the turntable 10 and the inner wall of the through hole 7, and the grid 21 is formed by weaving an elastic material; the guide and drainage plate 11 extends outward to form a cone-shaped structure; the overflow and drainage plate 9 is arranged as a plurality of folded structures, and the overflow and drainage plate 9 extends inward to form an inverted cone-shaped structure formed by a depression inside, and a plurality of support rods 22 are provided on the outer side and the inner side of the bottom of the overflow and drainage plate 9, and the bottoms of the support rods 22 are respectively fixed on the top of the first filter disc 6, and the top of the second filter disc 18 is provided with an overflow return plate 23, and the bottom of the rotating column 19 is fixed at the center of the overflow return plate 23, and the overflow and drainage plate 9 is provided with a plurality of filter holes, and an inner cylinder 24 is provided around the bottom of the turntable 10, and an activated carbon filter is provided on the outer wall of the inner cylinder 24, and an adsorption net is provided on the inner wall of the outer cylinder 8, and an adsorbent is provided on the adsorption net.

[0024] The inner cylinder 24 here rotates with the turntable 10, while the outer cylinder 8 is fixed. Therefore, the flow trajectory inside the cavity formed between the inner cylinder 24 and the outer cylinder 8 will change with the rotation of the inner cylinder 24, so that the sewage and light debris entering the cavity constantly hit the inner wall of the outer cylinder 8 and the adsorption net on the inner wall and the activated carbon filter net on the outer wall of the inner cylinder 24. Some of the filtered light debris are introduced into the second filter disc 18 under the rotation motion, and then driven outward by centrifugal action with the introduction of the overflow return plate 23, so as to be thrown into the heavy debris sedimentation tank 35 below, and discharged together with the heavy debris with the action of the scraper 32.

[0025] In addition, the inner wall of the sedimentation tank 14 is provided with a chute 25, the inner wall of the chute 25 is provided with an inner filter plate 26, a heavy debris sedimentation trough 35 is provided between the inner wall of the inner filter plate 26 and the side of the boss 15, and a guide groove 36 is left between any adjacent flow-displacing plates 16. The top of the boss 15 is provided with an arc-shaped baffle plate 27 near the upper side of the guide groove 36. The upper part of the rotating column 17 is sleeved with a disc 28, and the side of the disc 28 is provided with a plurality of upper connecting frames 29. The other end of the upper connecting frame 29 is provided with a column 30, and the bottom center of the column 30 is provided with a support rod 31. The support rod A scraper 32 is provided at the bottom of each column 31, a lower connecting frame 33 is connected to the outer side of each column 30, and a limiting wheel 34 is provided at one end of each lower connecting frame 33 away from the column 30, which cooperates with the slide groove 25, and the sewage outlet 4 is located at the heavy debris sedimentation tank 35; the column 30 is a cavity column, and a condenser is provided in the column 30, the upper connecting frame 29, the lower connecting frame 33 and the support rod 31 are all conduits, and the upper connecting frame 29, the lower connecting frame 33 and the support rod 31 are respectively connected to the column 30, the scraper 32 and the limiting wheel 34.

[0026] Detailed usage and function of this embodiment: Sewage is introduced into the sedimentation tank 1 from the sewage inlet pipe 3. After the liquid level of the sewage rises, the light debris contained in the sewage will go up with the sewage. When it passes through the first filter plate 6 and the overflow drainage plate 9 and is above the height intercepted by the overflow drainage plate 9, the externally connected control switch is driven to make its driver 13 run, driving the rotating shaft 12 to rotate. After the rotating shaft 12 rotates, it will drive the turntable 10 connected to the bottom to rotate. After the turntable 10 rotates, the upper guide drainage plate 11 will drive the sewage that has passed above to rotate. The light debris contained in the sewage forms a vortex trajectory under the action of the rotation force, and at the same time, it will hit the overflow drainage plate 9 on the side under the action of the movement of the vortex trajectory. The folding inclination angle of the overflow drainage plate 9 introduces the light debris that hits it into the through hole 7 in the middle. After the light debris gathers at the through hole 7, it flows from the grid 21 into the sandwich cavity formed between the outer cylinder 8 and the inner cylinder 24. Among them, when the turntable 10 is rotating, When the mesh 21 is pulled, it will pull the grid 21 connected to the side. Since the grid 21 is formed by the elastic material, the grid 21 will be twisted under the pulling of the rotational motion. At this time, the light debris passing by will bounce up with the deformation of the grid 21 to prevent the light debris from settling on the grid 21, and the grid 21 can play a certain intercepting role for the light debris rising from the bottom, reducing the phenomenon of the light debris rising. In addition, the angle at which the driver 13 drives the rotating shaft 12 to rotate is not 360 degrees, but it rotates back after rotating to a certain angle. That is to say, the rotational motion of the rotating shaft 12 always remains to rotate left and right. Through this reciprocating left and right rotation, the light debris brought up will change back and forth between collision and rebound in time to shorten the distance thrown out. If a 360-degree rotation is adopted, the distance thrown out of the light debris will be increased during the 360-degree rotation to prevent it from being thrown to the overflow port 2 after the distance is too large and discharged together with the sewage. Therefore, under this left-right rotation movement, the distance of the thrown-out object is limited, and the light debris is pulled back again after being thrown out. In this way, the fluidity around the rotating disk 10 is maintained, and the light debris is gathered at the through hole 7.

[0027] After the light debris enters the cavity formed between the outer cylinder 8 and the inner cylinder 24, it is adsorbed by the internal adsorption net and then contacts the activated carbon filter net on the surface of the inner cylinder 24 for filtration. The filtered light debris falls into the overflow return plate 23. When the inner cylinder 24 rotates, it drives the rotating column 19 connected to the bottom, and the rotating column 19 drives the second filter disc 18 to rotate. When the second filter disc 18 rotates, the light debris that falls into the overflow return plate 23 will diffuse around under the centrifugal motion, and be thrown out from the overflow return plate 23 to the boss 15 below and the heavy debris sedimentation tank 35.

[0028] After the heavy debris contained in the incoming sewage is precipitated on the boss 15, it slides into the heavy debris sedimentation tank 35 along the guide groove 36. When the second filter disc 18 rotates, it will drive the rotating column three 17 connected to the bottom to rotate, and the disc 28 mounted on the rotating column three 17 will rotate together, thereby driving the upper connecting frame 29 connected to the side. The upper connecting frame 29 pulls the column 30 to move, and the column 30 will drive the scraper 32 to scrape back and forth in the heavy debris sedimentation tank 35. During the scraping movement, the heavy debris precipitated in the heavy debris sedimentation tank 35 will be brought up, shortening the sedimentation time of the heavy debris, providing a certain guiding effect for the discharge of the heavy debris, and during the scraping During the removal process, after the condenser inside the column 30 works, the cold air generated will be transmitted to the upper connecting frame 29, the support rod 31, the scraper 32, the lower connecting frame 33 and the limiting wheel 34, wherein a plurality of micropores 1 may be provided on the bottom of the upper connecting frame 29, and a plurality of micropores 2 may be provided on the outer side of the lower connecting frame 33, that is, facing the inner wall of the sedimentation tank 1, so that the cold air generated inside can be transmitted out. After the column 30 rotates, the cold air will diffuse to the bottom of the sedimentation tank 1, so that the temperature inside the sedimentation tank 1 is maintained at a certain temperature. Under the effect of cooling, the odor generated in the sewage can be reduced, and at the same time, a certain control is provided for the heat generated during work.

[0029] Since the turntable 10 rotates back and forth, the rotation of the disc 28 is also a back-and-forth rotation, not a 360-degree rotation. When the column 30 rotates back and forth, the precipitated heavy debris will be brought up, shortening the sedimentation time of the heavy debris. By adopting this back-and-forth rotation trajectory, the distance thrown out can be shortened and the impact force hitting the inner wall can be reduced.

[0030] Through the above specific implementations, those skilled in the art can easily implement the present invention. However, it should be understood that the present invention is not limited to the above specific implementations. On the basis of the disclosed implementations, those skilled in the art can arbitrarily combine different technical features to achieve different technical solutions.

Claims

1. A multi-stage sewage treatment equipment, characterized in that: The sedimentation tank (1) comprises an overflow port (2) at the upper part of one side of the sedimentation tank (1), a sewage inlet pipe (3) is connected to the lower part of the side of the sedimentation tank (1) below the overflow port (2), a sewage outlet (4) is provided at the bottom of the sedimentation tank (1) away from the sewage inlet pipe (3), and a sewage outlet (4) is connected to the sewage outlet (5); A first filter disc (6) is provided near the center of the sedimentation tank (1), a through hole (7) is provided in the middle of the first filter disc (6), an outer cylinder (8) is provided at the through hole (7), an overflow guide plate (9) is provided at the top of the outer cylinder (8), a rotating disc (10) is provided in the middle of the overflow guide plate (9), a guide guide plate (11) is provided at the top of the rotating disc (10), a rotating shaft (12) is provided at the center of the top of the guide guide plate (11), and the top of the rotating shaft (12) passes through the sedimentation tank (1) and is connected to a driver (13) installed at the center of the outer top wall of the sedimentation tank (1); A sedimentation tank (1) is provided at the bottom of the sedimentation tank (1), a boss (15) is provided at the center of the sedimentation tank (14), a plurality of flow-displacing plates (16) are evenly provided on the top side of the boss (15), a rotating column three (17) is provided at the center of the top of the boss (15), a second filter disc (18) is provided at the top of the rotating column three (17), a rotating column two (19) is provided at the center of the top of the second filter disc (18), the rotating column two (19) passes through the through hole (7), a rotating column one (20) is provided at the top of the rotating column two (19), and the top of the rotating column one (20) is fixed at the bottom center of the rotating disk (10).

2. A multi-stage sewage treatment equipment according to claim 1, characterized in that: A grid (21) is provided between the rotating disk (10) and the inner wall of the through hole (7), and the grid (21) is formed by weaving an elastic material; The flow guide plate (11) extends outwards to form a cone-shaped structure; The overflow guide plate (9) is configured as a plurality of folded structures, and the overflow guide plate (9) extends inwardly to form a concave inverted cone-shaped structure inside.

3. A multi-stage sewage treatment equipment according to claim 1, characterized in that: A plurality of support rods (22) are provided on the outer side and the inner side of the bottom of the overflow guide plate (9), and the bottoms of the support rods (22) are respectively fixed on the top of the first filter disc (6).

4. A multi-stage sewage treatment equipment according to claim 1, characterized in that: An overflow return plate (23) is provided on the top of the second filter disc (18), and the bottom of the second rotating column (19) is fixed at the center of the overflow return plate (23).

5. The multi-stage sewage treatment equipment according to claim 1, characterized in that: The overflow guide plate (9) is provided with a plurality of filter holes, an inner cylinder (24) is provided around the bottom of the turntable (10), an activated carbon filter is provided on the outer wall of the inner cylinder (24), an adsorption net is provided on the inner wall of the outer cylinder (8), and an adsorbent is provided on the adsorption net.

6. The multi-stage sewage treatment equipment according to claim 1, characterized in that: The inner wall of the sedimentation tank (14) is provided with a chute (25), the inner wall of the chute (25) is provided with an inner filter plate (26), a heavy debris sedimentation trough (35) is provided between the inner wall of the inner filter plate (26) and the side of the boss (15), a guide groove (36) is left between any adjacent flow-displacing plates (16), and a curved baffle plate (27) is provided on one side of the top of the boss (15) close to the upper part of the guide groove (36).

7. A multi-stage sewage treatment equipment according to claim 6, characterized in that: A disc (28) is sleeved on the upper part of the rotating column (17), a plurality of upper connecting frames (29) are arranged on the side of the disc (28), a column (30) is arranged at the other end of each upper connecting frame (29), a support rod (31) is arranged at the bottom center of each column (30), a scraper (32) is arranged at the bottom of each support rod (31), a lower connecting frame (33) is connected to the outer side of each column (30), and a limiting wheel (34) matching with the slide groove (25) is arranged at one end of each lower connecting frame (33) away from the column (30).

8. The multi-stage sewage treatment equipment according to claim 7, characterized in that: The sewage outlet (4) is located at the heavy debris sedimentation tank (35); The column (30) is a hollow column. A condenser is arranged inside the column (30). The upper connecting frame (29), the lower connecting frame (33) and the support rod (31) are all conduits. The upper connecting frame (29), the lower connecting frame (33) and the support rod (31) are respectively connected to the inside of the column (30), the scraper (32) and the limiting wheel (34).

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