Environment-friendly sludge dewatering device and dewatering method thereof

Abstract

The invention discloses an environment-friendly sludge dewatering device and a dewatering method thereof, and relates to the technical field of sewage treatment device.The environment-friendly sludge dewatering device comprises a base, and a sludge feeding assembly, a dewatering assembly and a filtrate collecting assembly are arranged on the base; the sludge feeding assembly comprises a material guide groove and a conveying screw rod arranged in the material guide groove, and the output end of the top of the material guide groove faces a feeding opening of the dewatering assembly; the dewatering assembly comprises a barrel, a screen assembly arranged in the barrel and a driving mechanism for driving the screen assembly to rotate centrifugally, the screen assembly comprises an inner screen and an outer screen which are coaxially arranged, the inner screen is movably arranged in the outer screen, and the mesh diameter of the inner screen is larger than that of the outer screen; the filtrate collection assembly is arranged at the bottom of the dehydration assembly and is used for receiving separated liquid. The sludge dewatering device has the effect of improving the sludge dewatering efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment devices, and more particularly to an environment-friendly sludge dewatering device and its dewatering method. Background Art

[0002] At present, with the acceleration of urbanization and the improvement of environmental protection requirements, the sludge output increases year by year. How to efficiently and environmentally treat sludge has become an urgent problem to be solved. Currently, sludge treatment mainly includes four stages: thickening, conditioning, dewatering, and disposal. Among them, dewatering is the key link, which directly affects the subsequent disposal cost and effect. In recent years, mechanical dewatering technology has gradually become the mainstream due to its advantages such as high efficiency and small floor area. However, the existing technology still has problems such as high energy consumption, low dewatering rate, and secondary pollution.

[0003] Currently, the commonly used sludge dewatering technologies include belt filter press dewatering, plate and frame filter press dewatering, and centrifugal dewatering. Among them, centrifugal dewatering uses centrifugal force to separate water from sludge, with relatively high efficiency but high energy consumption and serious noise pollution.

[0004] Existing sludge dewatering devices mostly use a single-layer replaceable filter screen for separating sludge and liquid. The limitations of this structure are as follows: First, the single-layer filter screen is easily blocked and needs to be frequently replaced or cleaned, increasing the maintenance cost; second, the dewatering effect is not ideal, and the moisture content of the sludge is still relatively high, which is not conducive to subsequent disposal; third, in the face of sludge with different properties, the versatility is poor, and it is difficult to achieve targeted dewatering. Therefore, the use of a single-layer filter screen reduces the sludge dewatering efficiency. Summary of the Invention

[0005] This application provides an environment-friendly sludge dewatering device and its dewatering method, which has the effect of improving the sludge dewatering efficiency.

[0006] An environment-friendly sludge dewatering device and its dewatering method provided by this application adopt the following technical solutions: An environment-friendly sludge dewatering device and its dewatering method, wherein the environment-friendly sludge dewatering device includes a base, on which a sludge feeding component, a dewatering component, and a filtrate collecting component are provided; the sludge feeding component includes a guiding trough and a conveying screw arranged inside the guiding trough, and the output end at the top of the guiding trough faces the feeding port of the dewatering component; the dewatering component includes a cylinder body, a screen component arranged inside the cylinder body, and a driving mechanism for driving the screen component to rotate centrifugally. The feeding port is located at the top of the cylinder body. The screen component includes an inner screen and an outer screen arranged coaxially. The inner screen is movably arranged inside the outer screen and its mesh aperture is larger than that of the outer screen; the filtrate collecting component is arranged at the bottom of the dewatering component for receiving the separated liquid.

[0007] Preferably, an angle adjustment mechanism is provided between the bottom of the material guiding groove and the base. The angle adjustment mechanism includes a connecting seat hinged to the base and a hydraulic rod whose one end is rotatably connected to the base and the other end is connected to the bottom of the material guiding groove. The telescopic action of the hydraulic rod can make the material guiding groove rotate around the connecting seat to adjust the inclination angle.

[0008] Preferably, an annular filling area is formed between the inner screen and the outer screen of the screen assembly. A plurality of support grid pieces distributed around the central axis are arranged in the filling area. The support grid pieces are of a bent cross-section structure and include an embedded elastic metal skeleton.

[0009] Preferably, the support grid pieces are made of porous elastic non-woven fabric material, and the elastic metal skeleton is a metal wire in a snake shape and is embedded inside the non-woven fabric.

[0010] Preferably, an arc-shaped baffle is provided at the bottom of the inner wall of the cylinder body of the dehydration assembly. The arc-shaped baffle divides the inner cavity of the cylinder body into a dehydration area and a sludge accumulation area, and a sludge scraping mechanism is provided at the top of the cylinder body.

[0011] Preferably, the sludge scraping mechanism includes a rotating shaft driven by a second driving motor. The rotating shaft is connected with a swing rod that moves circumferentially along the inner wall of the cylinder body. A first scraper that fits the inner circle of the inner screen and a second scraper that fits the outer circle of the outer screen are respectively fixed on the mounting plate provided at the end of the swing rod.

[0012] Preferably, an electric push rod with adjustable telescopic amount is provided between the mounting plate and the first scraper. The electric push rod applies a pre-pressure to make the first scraper always keep in contact with the surface of the inner circle of the eccentrically rotating inner screen.

[0013] Preferably, an installation rod extending to the sludge accumulation area is also connected to the rotating shaft. A third scraper that fits the inner wall of the cylinder body is provided at the end of the installation rod for removing the accumulated sludge.

[0014] Preferably, the driving mechanism includes a first driving motor arranged outside the cylinder body. The output end of the first driving motor is connected with a spiral shaft that penetrates the center of the cylinder body. The centrifugal force generated by the rotation of the spiral shaft pushes the sludge to swing outward and contact the screen assembly.

[0015] Preferably, the dehydration method of the environmental protection type sludge dehydration device includes the following steps: S1. The sludge is input into the dehydration assembly through the material guiding groove by the conveying screw. S2. Start the driving mechanism to make the sludge be classified and filtered by the screen assembly under the action of centrifugal force, and the water is discharged through the outer screen to the filtrate collection assembly. S3. The scraping mechanism operates periodically, the first scraper and the second scraper remove the attachments on the surfaces of the inner and outer screens respectively, and the third scraper scrapes away the residues in the sludge accumulation area.

[0016] In summary, this application has the following beneficial effects: 1. An inner screen and an outer screen are arranged inside the cylinder, wherein the inner screen is movably arranged inside the outer screen, and the mesh diameter of the inner screen is larger than the mesh diameter of the outer screen. Under the action of the centrifugal rotation of the driving mechanism, the sludge mixed with water is thrown onto the inner screen and shakes inside the outer screen. By arranging a double-layer screen and making the inner screen movable, the efficiency of sludge dehydration can be effectively improved.

[0017] 2. When the sludge passes through the holes of the inner screen and enters the filling area, it will come into contact with the elastic non-woven fabric with built-in elastic metal wire. The porous elastic non-woven fabric is used to filter the sludge, and the supporting grid is a bent structure, which has a good supporting effect on the inner screen. During the centrifugal impact of the sludge, the inner screen can be quickly reset; during the resetting process of the inner screen, the supporting grid is reset under its own elastic action. At this time, the elastic non-woven fabric recovers from the compressed state to the extended state, which is used to improve the filtration efficiency; this dynamic "self-cleaning" effect reduces the possibility of blockage. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the overall structure of the environmentally friendly sludge dewatering device in this embodiment; Figure 2 Schematic diagram of the internal structure of the dehydration assembly in this embodiment; Figure 3 Schematic diagram of the internal structure of the screen assembly in this embodiment; Figure 4 It is a process flow chart in this embodiment; Explanation of the reference numerals: 1. base; 2. sludge feeding assembly; 201. guide trough; 202. conveying screw; 203. connecting seat; 204. hydraulic rod; 3. dehydration assembly; 301. cylinder; 302. first drive motor; 303. feed port; 304. screw shaft; 4. filtrate collecting assembly; 5. screen assembly; 501. inner screen; 502. outer screen; 503. supporting grid; 6. arc baffle; 7. fixing plate; 8. second drive motor; 9. rotating shaft; 10. rocker arm; 11. mounting plate; 12. first scraper; 13. second scraper; 14. positioning plate; 15. electric push rod; 16. mounting rod; 17. third scraper. DETAILED DESCRIPTION

[0019] The present application will be further described in detail below with reference to the accompanying drawings. It is necessary to point out here that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the protection scope of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content. Embodiment

[0020] The present invention discloses an environment-friendly sludge dewatering device and its dewatering method. As Figure 1 shown, the environment-friendly sludge dewatering device includes a base 1, a sludge feeding assembly 2 for guiding sludge provided on the base 1, a dewatering assembly 3 provided at the output end of the sludge feeding assembly 2, and a filtrate collecting assembly 4 fixed to the bottom of the dewatering assembly 3.

[0021] As Figure 1 shown, the sludge feeding assembly 2 guides the sludge into the interior of the dewatering assembly 3, and the dewatering of the sludge is achieved through the dewatering assembly 3. The separated wastewater falls into the interior of the filtrate collecting assembly 4, and the dewatered sludge is discharged through the output end of the dewatering assembly 3.

[0022] As Figure 1 shown, specifically, the sludge feeding assembly 2 includes a guiding trough 201. A rotatable conveying screw 202 is provided inside the guiding trough 201, and the top output end of the guiding trough 201 faces the input end of the dewatering assembly 3. By the rotation of the rotatable conveying screw 202, the sludge is introduced into the interior of the dewatering assembly 3 through the guiding trough 201 for dewatering operation.

[0023] As Figure 1 shown, the guiding trough 201 serves as a channel to guide the sludge from the sludge pool into the dewatering assembly 3, and the conveying screw 202 is the core of this system; it is located inside the guiding trough 201 and pushes the sludge forward through rotational movement; the thread design of the conveying screw 202 matches the characteristics of the sludge to achieve efficient conveyance; the top output end of the guiding trough 201 directly faces the input end of the dewatering assembly 3 to ensure that the sludge is accurately introduced into the dewatering assembly 3, avoiding waste and overflow.

[0024] As Figure 1As shown in the figure, further, a connecting seat 203 is fixedly installed at the central position of the material guiding groove 201. The connecting seat 203 is hinged to the base 1. A hydraulic rod 204 is provided on the base 1. The bottom of the hydraulic rod 204 is rotatably connected to the base 1. The top output end of the hydraulic rod 204 is connected to the bottom of the material guiding groove 201. When the hydraulic rod 204 expands and contracts, it will push or pull the bottom of the material guiding groove 201, forcing the material guiding groove 201 to rotate around the hinge point of the connecting seat 203. By controlling the expansion and contraction amount of the hydraulic rod 204, the rotation angle of the material guiding groove 201 can be precisely adjusted, and the angle of the material guiding groove 201 can be flexibly adjusted as needed.

[0025] As Figure 2 shown in the figure, the dehydration assembly 3 includes a cylinder body 301 and a first driving motor 302. The top of the cylinder body 301 is provided with a feed inlet 303. The top output end of the material guiding groove 201 faces the feed inlet 303 and is used to introduce sludge into the cavity inside the cylinder body 301 through the feed inlet 303. The first driving motor 302 is fixed on the base 1. The output end of the first driving motor 302 is connected with a spiral shaft 304. By the first driving motor 302, the spiral shaft 304 rotates at the central position of the cavity of the cylinder body 301. By using the centrifugal rotation of the spiral shaft 304, the sludge is thrown onto the screen assembly 5 arranged in the sleeve cavity. The water in the sludge overflows along the mesh holes of the screen assembly 5, while the sludge adheres to the inner wall of the screen assembly 5. Under the action of gravity, the drained water is discharged into the interior of the filtrate collection assembly 4 through the liquid outlet at the bottom of the cylinder body 301.

[0026] As Figure 2 shown in the figure, the sludge enters the rotating cylinder body 301 through the material guiding groove 201. The first driving motor 302 drives the spiral shaft 304 to rotate at a high speed. The rotation of the spiral shaft 304 generates a strong centrifugal force, which throws the sludge towards the cylinder wall. The sludge is thrown onto the screen assembly 5 on the cylinder wall. Due to the action of the centrifugal force, the water in the sludge is more likely to pass through the mesh holes of the screen. The water is discharged through the screen and flows into the filtrate collection assembly 4 through the liquid outlet at the bottom of the cylinder body 301. The solid sludge particles are retained on the inner wall of the screen. The centrifugal force can significantly improve the dehydration efficiency. Compared with natural precipitation or gravity filtration, the dehydration speed is faster and the dehydration effect is better.

[0027] As Figure 2As shown in the figure, the screen assembly 5 includes an inner screen 501 and an outer screen 502 arranged coaxially. Among them, the outer screen 502 is fixed inside the cylinder body 301, the central axis of the outer screen 502 coincides with the central axis of the cylinder body 301, the inner screen 501 is movably arranged inside the outer screen 502, and the pore size of the inner screen 501 is larger than that of the outer screen 502. First, the inner screen 501 plays a role in preliminary filtration, intercepting larger particle impurities or unwanted solids and allowing smaller particles to pass through; then, the smaller particles passing through the inner screen 501 are further filtered by the outer screen 502, blocking smaller impurities or solids outside; in this way, hierarchical filtration is achieved, improving the filtration efficiency and accuracy.

[0028] As Figure 2 shown, moreover, the existence of the inner screen 501 can effectively protect the outer screen 502; since the inner screen 501 intercepts most of the larger particles first, it reduces the blockage and wear of the outer screen 502, extends the service life of the outer screen 502, and at the same time ensures the effectiveness of the outer screen 502 in filtration; after the larger particles are intercepted by the inner screen 501, the direct impact and pressure on the outer screen 502 are reduced, the resistance of the sludge passing through the screen is lowered, and the filtration speed and efficiency are improved.

[0029] As Figure 3 shown, an annular filling area is formed between the outer ring of the inner screen 501 and the inner ring of the outer screen 502. A number of support grid sheets 503 are arranged in the filling area. The support grid sheets 503 are distributed at equal angles around the central axis of the filling area, and the cross-section of the support grid sheet 503 is a bent structure. Moreover, the material of the support grid sheet 503 is a porous elastic non-woven fabric, and elastic metal wires in a serpentine structure are evenly distributed inside the elastic non-woven fabric; the serpentine elastic metal wires are embedded inside the non-woven fabric, playing a role similar to a skeleton; when the non-woven fabric is compressed, the metal wires will also deform and store a part of elastic potential energy; when the support grid sheet 503 starts to reset, the metal wires will release this potential energy, further accelerating the recovery of the non-woven fabric and enhancing the anti-deformation ability of the entire support structure.

[0030] As Figure 3 shown, when the sludge passes through the holes of the inner screen 501 and enters the filling area, it will contact the elastic non-woven fabric with built-in elastic metal wires, and the porous elastic non-woven fabric is used to realize the filtration of the sludge. The support grid sheet 503 is in a bent structure and has a good effect of supporting the inner screen 501. During the centrifugal impact of the sludge, the inner screen 501 can quickly reset; during the reset process of the inner screen 501, the support grid sheet 503 resets under its own elastic action. At this time, the elastic non-woven fabric returns from the compressed state to the extended state to improve the filtration efficiency; this dynamic "self-cleaning" effect reduces the possibility of blockage.

[0031] As shown Figure 3 in the figure, the bent structure endows it with a certain deformation space; when the inner screen 501 is impacted by centrifugal force, the supporting grid pieces 503 are deformed (bent or compressed); when the centrifugal force decreases and the inner screen 501 needs to reset, the bent supporting grid pieces 503 will utilize the elasticity of their own materials and attempt to return to the original bent shape, thereby generating an outward thrust to help the inner screen 501 reset; the elastic non-woven fabric itself has elasticity and can be compressed and stretched; when the inner screen 501 is impacted, the elastic non-woven fabric will be compressed due to the deformation of the supporting grid pieces 503; when the supporting grid pieces 503 reset, the elastic non-woven fabric also returns to the extended state; the synergistic effect of the bent structure and the elastic non-woven fabric provides a stronger reset power, enabling the inner screen 501 to return to the original position faster and more thoroughly; this is crucial for improving the efficiency and continuity of sludge filtration; moreover, the recovery of the elastic non-woven fabric from the compressed state to the extended state can help remove the residual sludge particles in the pores of the non-woven fabric and keep the filtration holes unblocked, thereby improving the filtration efficiency; this dynamic "self-cleaning" effect reduces the possibility of blockage.

[0032] As shown Figure 3 in the figure, an arc-shaped baffle 6 is provided at the bottom of the cavity of the cylinder body 301, and the arc-shaped baffle 6 divides the bottom of the cavity into a dehydration area and a sludge accumulation area. A fixing plate 7 is fixedly installed at the top of the cavity of the cylinder body 301, a second driving motor 8 is fixedly installed on the fixing plate 7, the output end of the second driving motor 8 is connected with a rotating shaft 9, the central axis of the rotating shaft 9 coincides with the central axis of the cylinder body 301, a swing rod 10 is fixedly installed on the rotating shaft 9, one end of the swing rod 10 is fixedly connected to the rotating shaft 9, the other end of the swing rod 10 is provided with a mounting plate 11, a first scraper 12 and a second scraper 13 are arranged on the mounting plate 11, the first scraper 12 is attached to the inner surface of the inner circle of the inner screen 501, the second scraper 13 is attached to the outer surface of the outer circle of the outer screen 502. By driving the rotating shaft 9 by the second driving motor 8, the swing rod 10 makes a circular motion. The first scraper 12 is used to separate the dehydrated sludge attached to the inner surface of the inner circle of the inner screen 501, and through the rotation of the spiral shaft 304, the separated sludge is guided into the sludge accumulation area. The second scraper 13 is used to remove the sludge impurities on the outer surface of the outer screen 502.

[0033] As shown Figure 3 in the figure, the designs of the first scraper 12 and the second scraper 13 can effectively separate the sludge on the surfaces of the inner screen 501 and the outer screen 502, maintain the permeability of the inner screen 501 and the outer screen 502, and thus improve the dehydration efficiency; the combination of the inner screen 501 and the outer screen 502 for double filtration has a better separation effect.

[0034] As shownFigure 3 As shown, further, a positioning plate 14 is provided on the mounting plate 11, an electric push rod 15 is provided on the positioning plate 14, and the output end of the electric push rod 15 is connected to the first scraper 12 for adjusting the telescopic movement of the first scraper 12 so that the first scraper 12 abuts against the inner ring of the inner screen 501 and applies an appropriate pressure. Since the inner screen 501 is movably arranged inside the outer screen 502, the inner screen 501 rotates eccentrically inside the outer screen 502, and the inner screen 501 is used to extrude the support grid 503 in the filling area to clean the sludge impurities remaining on the support grid 503.

[0035] As Figure 3 shown, the inner screen 501 rotates eccentrically inside the outer screen 502, which means that the center of the inner screen 501 is not the center of the outer screen 502; when the inner screen 501 rotates, the distance between it and the support grid 503 changes continuously, thus generating extrusion and friction; the first scraper 12 adjusted by the electric push rod 15 abuts against the inner ring of the inner screen 501 and applies pressure; the function of the first scraper 12 is to assist in cleaning, further scraping off the sludge impurities extruded by the inner screen 501 and maintaining an appropriate pressure between the inner screen 501 and the support grid 503; as the inner screen 501 rotates eccentrically, it continuously extrudes the support grid 503, and at the same time the first scraper 12 provides pressure and scraping; the sludge impurities fall off from the support grid 503 under the combined action of extrusion, friction and scraping; the combined action of eccentric rotation and the first scraper 12 can effectively clean the sludge impurities on the support grid 503 and improve the cleaning efficiency.

[0036] An installation rod 16 is provided on the rotating shaft 9. One end of the installation rod 16 is fixedly connected to the rotating shaft 9, and the other end of the installation rod 16 is connected with a third scraper 17. The third scraper 17 is attached to the inner surface of the sludge accumulation area of the cylinder body 301 for scraping the dewatered sludge accumulated in the sludge accumulation area.

[0037] Based on the above environmental protection type sludge dewatering device, the dewatering method of the environmental protection type sludge dewatering device includes the following dewatering steps: S1: Sludge feeding; By using the telescopic movement of the hydraulic rod 204 to push or pull the bottom of the material guiding groove 201, forcing the material guiding groove 201 to rotate around the hinge point of the connecting seat 203, making the material guiding groove 201 tilt towards the sludge pool, and starting the conveying screw 202. The conveying screw 202 is located inside the material guiding groove 201. Through the rotational movement of the conveying screw 202, the sludge is guided from the sludge pool into the inside of the feed port 303. S2: Dewatering treatment; The sludge enters the interior of the rotating cylinder 301 through the material guiding trough 201; the first driving motor 302 drives the spiral shaft 304 to rotate at a high speed; the rotation of the spiral shaft 304 generates a strong centrifugal force, which throws the sludge towards the cylinder wall; the sludge is thrown onto the screen assembly 5 on the cylinder wall; due to the action of the centrifugal force, the water in the sludge passes through the mesh holes of the inner screen 501 and the outer screen 502 for the dehydration treatment of the sludge; S3: Filtrate collection; It flows into the filtrate collection assembly 4 through the liquid outlet at the bottom of the cylinder 301; while the solid sludge particles are intercepted on the inner wall of the screen; S4: Sludge discharge; The second driving motor 8 drives the rotating shaft 9 to make the swing rod 10 perform a circular motion. The first scraper 12 is used to separate the dehydrated sludge attached to the inner surface of the inner circle of the inner screen 501, and the rotation of the spiral shaft 304 is used to guide the separated sludge into the sludge accumulation area; S5: Sludge cleaning; The second scraper 13 is used to remove the sludge impurities on the outer surface of the outer circle of the outer screen 502, and the third scraper 17 attached to the inner surface of the inner circle of the sludge accumulation area of the cylinder 301 is used to scrape the dehydrated sludge accumulated in the sludge accumulation area.

[0038] The above are all the preferred embodiments of this application. The protection scope of this application is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of this application shall be covered within the protection scope of this application.

Claims

1. An environmentally friendly sludge dewatering device, comprising a base (1), characterized in that: A sludge feeding assembly (2), a dewatering assembly (3) and a filtrate collecting assembly (4) are arranged on the base (1); the sludge feeding assembly (2) includes a material guiding groove (201) and a conveying screw (202) arranged inside the material guiding groove (201), and the top output end of the material guiding groove (201) faces the feeding port (303) of the dewatering assembly (3); the dewatering assembly (3) includes a cylinder body (301), a screen assembly (5) arranged inside the cylinder body (301) and a driving mechanism for driving the screen assembly (5) to rotate centrifugally, the feeding port (303) is located at the top of the cylinder body (301), the screen assembly (5) includes an inner screen (501) and an outer screen (502) arranged coaxially, the inner screen (501) is movably arranged inside the outer screen (502) and the pore diameter of its mesh is larger than that of the outer screen (502); the filtrate collecting assembly (4) is arranged at the bottom of the dewatering assembly (3) for receiving the separated liquid.

2. The environmentally friendly sludge dewatering device according to claim 1, wherein: An angle adjusting mechanism is arranged between the bottom of the material guiding groove (201) and the base (1), the angle adjusting mechanism includes a connecting seat (203) hinged to the base (1) and a hydraulic rod (204) with one end rotatably connected to the base (1) and the other end connected to the bottom of the material guiding groove (201), and the telescopic movement of the hydraulic rod (204) enables the material guiding groove (201) to rotate around the connecting seat (203) to adjust the inclination angle.

3. The environmentally friendly sludge dewatering device according to claim 2, characterized in that: An annular filling area is formed between the inner screen (501) and the outer screen (502) of the screen assembly (5), and a plurality of support grid plates (503) distributed around the central axis are arranged in the filling area, and the support grid plates (503) are of a bent cross-section structure and include an embedded elastic metal skeleton.

4. The environmentally friendly sludge dewatering device according to claim 3, wherein: The support grid plates (503) are made of porous elastic non-woven fabric material, and the elastic metal skeleton is a metal wire in a snake shape and is embedded inside the non-woven fabric.

5. The environmentally friendly sludge dewatering device according to claim 4, wherein: An arc-shaped baffle (6) is arranged at the bottom of the inner wall of the cylinder body (301) of the dewatering assembly (3), the arc-shaped baffle (6) divides the inner cavity of the cylinder body (301) into a dewatering area and a sludge accumulation area, and a sludge scraping mechanism is arranged at the top of the cylinder body (301).

6. The environmentally friendly sludge dewatering device according to claim 5, characterized in that: The sludge scraping mechanism includes a rotating shaft (9) driven by a second driving motor (8), the rotating shaft (9) is connected with a swing rod (10) moving circumferentially along the inner wall of the cylinder body (301), and a first scraper (12) fitting the inner circle of the inner screen (501) and a second scraper (13) fitting the outer circle of the outer screen (502) are respectively fixed on a mounting plate (11) arranged at the end of the swing rod (10).

7. The environmentally friendly sludge dewatering device according to claim 6, characterized in that: An electric push rod (15) with an adjustable telescopic amount is arranged between the mounting plate (11) and the first scraper (12), and the electric push rod (15) applies a pre-pressure to keep the first scraper (12) always in contact with the inner circle surface of the eccentrically rotating inner screen (501).

8. The environmentally friendly sludge dewatering device according to claim 7, wherein: An installation rod (16) extending to the sludge accumulation area is further connected to the rotating shaft (9), and a third scraper (17) fitting the inner wall of the cylinder body (301) is arranged at the end of the installation rod (16) for removing the accumulated sludge.

9. The environmentally friendly sludge dewatering device according to claim 8, wherein: The driving mechanism comprises a first driving motor (302) arranged outside the cylinder (301); the output end of the first driving motor (302) is connected to a screw shaft (304) penetrating the center of the cylinder (301); the centrifugal force generated by the rotation of the screw shaft (304) pushes the sludge to be thrown outwards and contact the screen assembly (5).

10. A dehydration method for the environmentally friendly sludge dewatering device according to any one of claims 1-9, characterized in that, The following steps are involved: S1. The sludge is fed into the interior of the dehydration assembly (3) through the conveying screw (202) and the guide trough (201); S2. The driving mechanism is started to cause the sludge to be graded and filtered through the screen assembly (5) under the action of centrifugal force, and the water is discharged to the filtrate collection assembly (4) through the outer screen (502); S3. The sludge scraping mechanism operates periodically, the first scraper (12) and the second scraper (13) respectively remove the attached materials on the surface of the inner screen (501) and the outer screen (502), and the third scraper (17) scrapes away the residue in the sludge accumulation area.

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