Sludge concentrating and discharging system for treating phenylenediamine production wastewater

Abstract

The invention discloses a sludge concentration and discharge system for phenylenediamine production wastewater treatment, and relates to the technical field of phenylenediamine production.The sludge concentration and discharge system comprises a concentration tank, the concentration tank is installed on a support, a sludge hopper is arranged at the bottom end of the concentration tank, a clear water overflow opening is formed in one side of the concentration tank, and a dosing mixing tank is installed on the support; a sewage inlet pipe is arranged on one side of the dosing mixing tank, and a sewage discharge pipe is arranged on the other side of the dosing mixing tank. A multi-stage annular overflow disc is arranged in the dosing mixing tank, sewage is uniformly scattered to the annular overflow disc through a distributor, a cylindrical water film overflowing layer by layer is formed, the contact area between the sewage and an atomized flocculant is increased, sufficient mixing of the sewage and the atomized flocculant is promoted, a third rotating motor drives the distributor and an annular connector to rotate in the reverse direction, and therefore the sewage can be fully mixed. The sewage and the flocculating agent are more uniformly dispersed in relative movement, so that the dosage of the agent is reduced, and the cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of phenylenediamine production, and particularly to a sludge concentration and discharge system for treating wastewater in phenylenediamine production. Background Art

[0002] The wastewater generated during the production of phenylenediamine contains a large amount of organic matter, suspended solids and toxic substances, and pollutants need to be removed through sludge concentration treatment. The traditional sludge concentration and discharge system has the following problems:

[0003] 1. Insufficient flocculation mixing: The contact area between the sewage and the flocculant is limited, and the mixing is uneven, resulting in low flocculation efficiency, small sludge particles and poor concentration effect.

[0004] 2. Incomplete sludge cleaning: The sludge at the bottom of the concentration tank is easily adhered to the tank wall, and it is difficult for the traditional scraping device to effectively remove it, affecting the sludge collection efficiency.

[0005] 3. Difficult control of chemical dosage: Lack of a precise flow matching mechanism, which is easy to cause waste or insufficient dosing of the flocculant, increasing the treatment cost.

[0006] In view of the above problems, the present invention provides a sludge concentration and discharge system with optimized structure, which improves the treatment efficiency and reduces the operation cost through efficient mixing, intelligent scraping and stable sludge discharge design. Summary of the Invention

[0007] In order to solve the problems mentioned in the above background art, the present invention provides a sludge concentration and discharge system for treating wastewater in phenylenediamine production.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A sludge concentration and discharge system for treating wastewater in phenylenediamine production, including a concentration tank, the concentration tank is installed on a bracket, a sludge hopper is provided at the bottom end of the concentration tank, a clear water overflow port is provided on one side of the concentration tank, a chemical dosing and mixing tank is installed on the bracket, a sewage inlet pipe is provided on one side of the chemical dosing and mixing tank, a sewage discharge pipe is provided on the other side of the chemical dosing and mixing tank, a support bridge is provided directly above the concentration tank, a stirring container is provided below the support bridge, the sewage discharge pipe is communicated with the stirring container, a scraper is further provided below the support bridge, and a sludge discharge mechanism is provided below the sludge hopper.

[0010] Preferably, a rotating shaft is provided below the support bridge, the scraper is fixed below the rotating shaft, and the rotating shaft is driven to rotate by a first rotating motor.

[0011] Preferably, the rotating shaft penetrates through the stirring container, and a stirrer is fixed at one end of the rotating shaft located inside the stirring container, and a plurality of inclined sludge scraping plates are provided below the scraper.

[0012] Preferably, the sludge discharging mechanism includes a sludge discharge pump. The sludge inlet of the sludge discharge pump is connected to the bottom end of the sludge hopper. A second rotating motor is installed above the sludge discharge pump. Pulley wheels are installed on both the power input shaft of the sludge discharge pump and the output shaft of the second rotating motor, and the two pulley wheels are driven by a belt.

[0013] Preferably, a flow meter is installed on the sewage inlet pipe. One end of the sewage inlet pipe extends into the dosing and mixing tank and bends vertically upward. The top end of the sewage inlet pipe is rotatably connected to a distributor. A plurality of annular overflow plates are rotatably installed in the dosing and mixing tank from top to bottom.

[0014] Preferably, a plurality of water outlet pipes are arranged in an array around the distributor. The water outlet of the water outlet pipe is aligned with the uppermost annular overflow plate. A section of the annular overflow plate close to the inner wall of the annular overflow plate is a horizontal section. The side of the annular overflow plate away from the inner wall of the annular overflow plate bends upward to form an overflow surface, and the inner diameters of the plurality of annular overflow plates gradually decrease from top to bottom.

[0015] Preferably, a flocculant introduction pipe and a drive box are provided at the top end of the dosing and mixing tank. One end of the flocculant introduction pipe extends into the drive box and is connected to a rotating pipe through a rotary joint. The bottom end of the rotating pipe extends into the dosing and mixing tank and is fixed to the top end of the distributor.

[0016] Preferably, an annular connector is rotatably installed outside the rotating pipe. A plurality of through holes are provided in the rotating pipe inside the annular connector. A plurality of flocculant discharge pipes are installed outside the annular connector. The end of the flocculant discharge pipe away from the annular connector obliquely passes through the inner circle of each annular overflow plate and is fixed to the bottom end of the lowermost annular overflow plate. The annular overflow plates are fixed to each other through a connecting frame.

[0017] Preferably, a plurality of atomizing nozzles are equidistantly distributed at positions between adjacent annular overflow plates outside the flocculant discharge pipe.

[0018] Preferably, a third rotating motor is installed at the top end of the drive box. The output shaft of the third rotating motor extends into the drive box and is fixed with a first gear. A second gear is fixed outside the rotating pipe. The first gear meshes with the second gear. A toothed ring is fixed between the top ends of the plurality of flocculant discharge pipes. The output shaft of the third rotating motor extends into the dosing and mixing tank and is fixed with a third gear. The third gear meshes with the inner circle of the toothed ring. A plurality of flow-around components are installed on the inner wall of the dosing and mixing tank at positions corresponding to the annular overflow plates.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. A multi - stage annular overflow tray is arranged inside the chemical dosing and mixing tank. Sewage is evenly scattered onto the annular overflow tray through a distributor, forming a cylindrical water film that overflows layer by layer, increasing the contact area with the atomized flocculant, promoting the full mixing of the two. The third rotating motor drives the distributor and the annular connector to rotate in opposite directions, enabling the sewage and the flocculant to be more evenly dispersed during relative movement, reducing the dosage of the chemical agent and lowering the cost.

[0021] 2. The scraping device drives the rotating shaft to rotate through the first rotating motor. The inclined sludge scraping plate fits the inner wall of the bottom of the thickening tank, scraping the adhered sludge into the sludge hopper, avoiding sludge residue from affecting the thickening efficiency. The rotating shaft penetrates the stirring container and synchronously drives the internal stirrer, accelerating the flocculation reaction to form large - particle sludge, facilitating subsequent thickening and collection.

[0022] 3. A flow meter is installed on the sewage inlet pipe to monitor the flow rate in real - time and adjust the dosage of the flocculant, avoiding waste or shortage of the chemical agent. The atomizing nozzles are evenly distributed on the flocculant discharge pipe to ensure that the flocculant contacts the water film in a mist state, improving the mixing efficiency and reducing the consumption of the chemical agent. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0024] Figure 1 is a perspective view of the present invention;

[0025] Figure 2 is a top view of the present invention;

[0026] Figure 3 is a right - hand view of the present invention;

[0027] Figure 4 is a front view of the present invention;

[0028] Figure 5 is a schematic structural view of the scraping device of the present invention;

[0029] Figure 6 is a schematic structural view of the sludge discharge mechanism of the present invention;

[0030] Figure 7 is a perspective view of the chemical dosing and mixing tank of the present invention;

[0031] Figure 8 is a perspective cross - sectional view of the chemical dosing and mixing tank of the present invention;

[0032] Figure 9It is a main perspective sectional view of the chemical dosing and mixing tank of the present invention;

[0033] Figure 10 It is a diagram showing the relative positional relationship between the internal water outlet pipe and the annular overflow tray of the chemical dosing and mixing tank of the present invention;

[0034] Figure 11 It is a diagram showing the relative positional relationship between the flocculant discharge pipe and the annular overflow tray of the present invention;

[0035] Figure 12 It is a three-dimensional internal structure sectional view of the chemical dosing and mixing tank of the present invention;

[0036] In the figure: 1. Bracket; 2. Thickening tank; 201. Clear water overflow port; 202. Sludge hopper; 203. Sludge discharge pump; 204. Second rotating motor; 205. Belt; 3. Sewage inlet pipe; 301. Sewage discharge pipe; 302. Stirring container; 303. Flowmeter; 4. First rotating motor; 401. Rotating shaft; 402. Scraper; 4021. Mud scraper; 403. Stirrer; 5. Chemical dosing and mixing tank; 501. Driving box; 502. Third rotating motor; 5021. First gear; 5022. Third gear; 503. Flocculant introduction pipe; 5031. Rotary joint; 504. Rotating pipe; 5041. Second gear; 5042. Through hole; 505. Flow-around component; 6. Annular overflow tray; 601. Connecting frame; 7. Distributor; 701. Water outlet pipe; 8. Annular connector; 801. Flocculant discharge pipe; 802. Tooth ring; 803. Atomizing nozzle. Detailed implementation manners

[0037] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0038] Embodiment 1

[0039] Refer to Figures 1-12, A sludge thickening and discharging system for treating the wastewater from p-phenylenediamine production, which includes a thickening tank 2 installed on a bracket 1. A sludge hopper 202 is provided at the bottom end of the thickening tank 2, and a clear water overflow port 201 is provided on one side of the thickening tank 2. A chemical dosing and mixing tank 5 is installed on the bracket 1. A sewage inlet pipe 3 is provided on one side of the chemical dosing and mixing tank 5, and a sewage outlet pipe 301 is provided on the other side of the chemical dosing and mixing tank 5. A support bridge is provided directly above the thickening tank 2. A stirring container 302 is provided below the support bridge. The sewage outlet pipe 301 is communicated with the stirring container 302. A scraping device 402 is also provided below the support bridge. A sludge discharging mechanism is provided below the sludge hopper 202;

[0040] The sewage first enters the chemical dosing and mixing tank 5 through the sewage inlet pipe 3, and then is uniformly mixed with the flocculant in the chemical dosing and mixing tank 5 (the retention time of the flocculant and the sewage in the chemical dosing and mixing tank 5 is relatively short, generally within five minutes, and no obvious flocculation and precipitation occur to the sewage during this period). The sewage with the flocculant after mixing enters the stirring container 302 from the sewage outlet pipe 301. After stirring, it accelerates solidification, and finally forms large particle sludge and falls into the sludge hopper 202 at the bottom end of the thickening tank 2. The scraping device 402 is used to scrape the inner wall at the bottom end of the thickening tank 2 to ensure that the sludge can fall into the sludge hopper 202. The concentrated sludge collected in the sludge hopper 202 is discharged through the sludge discharging mechanism, and the supernatant after treatment flows out through the clear water overflow port 201.

[0041] Example 2

[0042] Refer to Figures 1-12 , The difference between this example and Example 1 is that a rotating shaft 401 is provided below the support bridge. The scraping device 402 is fixed below the rotating shaft 401, and the rotating shaft 401 is driven to rotate by a first rotating motor 4. The rotating shaft 401 penetrates through the stirring container 302, and a stirrer 403 is fixed at one end of the rotating shaft 401 located inside the stirring container 302. A plurality of inclined scraping plates 4021 are provided below the scraping device 402;

[0043] The first rotating motor 4 drives the rotating shaft 401 to rotate, thereby driving the scraping device 402 to rotate. The scraping plates 4021 on the scraping device 402 move along the inner wall at the bottom end of the thickening tank 2, scraping the sludge accumulated on the inner wall at the bottom end of the thickening tank 2 to loosen it, so that the sludge can slide into the sludge hopper 202.

[0044] Example 3

[0045] Refer to Figures 1-12, the difference between this embodiment and Embodiment 1 is that the sludge discharging mechanism includes a sludge discharging pump 203. The sludge inlet of the sludge discharging pump 203 is connected to the bottom end of the sludge hopper 202. A second rotating motor 204 is installed above the sludge discharging pump 203. Pulley wheels are installed on both the power input shaft of the sludge discharging pump 203 and the output shaft of the second rotating motor 204, and the two pulley wheels are driven by a belt 205;

[0046] Power is input through the second rotating motor 204, and the belt 205 transmits the power to the sludge discharging pump 203, and the concentrated sludge is discharged through the sludge discharging pump 203.

[0047] Embodiment 4

[0048] Refer to Figures 1-12 , the difference between this embodiment and Embodiment 1 is that a flow meter 303 is installed on the sewage inlet pipe 3, and one end of the sewage inlet pipe 3 extends into the internal part of the chemical dosing and mixing tank 5 and bends vertically upward, and the top end of the sewage inlet pipe 3 is rotatably connected to a distributor 7. A plurality of annular overflow trays 6 are rotatably installed in the chemical dosing and mixing tank 5 from top to bottom. A plurality of water outlet pipes 701 are arranged in an array around the distributor 7, and the water outlet of the water outlet pipe 701 is aligned with the uppermost annular overflow tray 6. A section of the annular overflow tray 6 close to the inner wall of the annular overflow tray 6 is a horizontal section, and one side of the annular overflow tray 6 away from the inner wall of the annular overflow tray 6 bends upward to form an overflow surface, and the inner diameters of the plurality of annular overflow trays 6 decrease step by step from top to bottom;

[0049] The sewage introduced into the sewage inlet pipe 3 first enters the distributor 7, and then is evenly sprinkled into the uppermost annular overflow tray 6 through the plurality of water outlet pipes 701. When the annular overflow tray 6 is filled with liquid, it will flow out from the bent arc-shaped overflow surface to form a cylindrical water film. Since the inner diameters of the plurality of annular overflow trays 6 decrease step by step from top to bottom, the sewage overflowing from the upper annular overflow tray 6 can fall into the next-level annular overflow tray 6, and then flow down step by step, and finally fall to the bottom of the chemical dosing and mixing tank 5.

[0050] Among them, a flocculant introduction pipe 503 and a drive box 501 are provided at the top end of the chemical dosing and mixing tank 5. One end of the flocculant introduction pipe 503 extends into the drive box 501 and is connected to a rotating pipe 504 through a rotary joint 5031. The bottom end of the rotating pipe 504 extends into the internal part of the chemical dosing and mixing tank 5 and is fixed to the top end of the distributor 7;

[0051] The flocculant solution is introduced into the rotating pipe 504 through the flocculant introduction pipe 503. An annular connector 8 is rotatably installed outside the rotating pipe 504. A plurality of through holes 5042 are provided on the rotating pipe 504 inside the annular connector 8. A plurality of flocculant discharge pipes 801 are installed outside the annular connector 8. One end of the flocculant discharge pipe 801 away from the annular connector 8 obliquely passes through the inner ring of each annular overflow plate 6 and is fixed to the bottom end of the lowermost annular overflow plate 6. Each annular overflow plate 6 is fixed to each other through a connecting frame 601. The flocculant solution flows into the annular connector 8 through the through holes 5042 and is then evenly distributed into a plurality of flocculant discharge pipes 801 through the annular connector 8. A plurality of atomizing nozzles 803 are equidistantly distributed at positions between adjacent annular overflow plates 6 outside the flocculant discharge pipe 801. The flocculant solution is ejected through the atomizing nozzles 803, and the atomizing nozzles 803 are exactly aligned with the water films of each columnar shape, so that it can be evenly mixed with the sewage. Finally, the sewage mixed with the flocculant falls to the bottom end of the chemical addition mixing tank 5, thus completing efficient and uniform mixing;

[0052] The flow rate of the sewage can be detected in real time through the flow meter 303, so as to correspondingly adjust the addition flow rate of the flocculant solution, ensure the matching of the two, and avoid the problems of poor flocculation effect due to too little addition of the flocculant or waste of the flocculant due to too much addition of the flocculant.

[0053] Example 5

[0054] Refer to Figures 1-12 In this example, the difference from Example 3 is that a third rotating motor 502 is installed at the top end of the drive box 501. The output shaft of the third rotating motor 502 extends into the drive box 501 and is fixed with a first gear 5021. A second gear 5041 is fixed outside the rotating pipe 504. The first gear 5021 meshes with the second gear 5041. A toothed ring 802 is fixed between the top ends of a plurality of flocculant discharge pipes 801. The output shaft of the third rotating motor 502 extends into the chemical addition mixing tank 5 and is fixed with a third gear 5022. The third gear 5022 meshes with the inner ring of the toothed ring 802. A plurality of flow-around components 505 are installed on the inner wall of the chemical addition mixing tank 5 at positions corresponding to the annular overflow plates 6;

[0055] By starting the third rotating motor 502, the first gear 5021 can be driven to rotate. Through the meshing of the first gear 5021 and the second gear 5041, the rotating pipe 504 can be driven to rotate in the same direction as the third rotating motor 502. By the third rotating motor 502, the third gear 5022 can be driven to rotate. Thus, through the meshing of the third gear 5022 and the inner ring of the toothed ring 802, the annular connector 8 can be driven to rotate in the reverse direction. Therefore, the distributor 7 and the annular connector 8 rotate in opposite directions. The annular connector 8 can drive the annular overflow tray 6 to rotate through the flocculant discharge pipe 801. Since the distributor 7 and the annular overflow tray 6 rotate relatively, the water distribution uniformity of the water outlet pipe 701 can be improved.

[0056] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0057] In the present invention, unless otherwise clearly defined and limited, the terms "set", "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium. It can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0058] The control mode of the present invention is automatically controlled by a controller. The control circuit of the controller can be realized by simple programming by those skilled in the art. The provision of power also belongs to the common knowledge in the art. And the present invention is mainly used to protect mechanical devices. Therefore, the control mode and circuit connection of the present invention will not be explained in detail.

[0059] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A sludge concentration and discharge system for treating the wastewater produced in the production of phenylenediamine, comprising a thickening tank (2), characterized in that: The thickener (2) is installed on the bracket (1). A sludge hopper (202) is provided at the bottom end of the thickener (2). A clear water overflow port (201) is provided on one side of the thickener (2). A chemical dosing and mixing tank (5) is installed on the bracket (1). A sewage inlet pipe (3) is provided on one side of the chemical dosing and mixing tank (5). A sewage discharge pipe (301) is provided on the other side of the chemical dosing and mixing tank (5). A support bridge is provided directly above the thickener (2). A stirring container (302) is provided below the support bridge. The sewage discharge pipe (301) is communicated with the stirring container (302). A scraping device (402) is also provided below the support bridge. A sludge discharging mechanism is provided below the sludge hopper (202).

2. The sludge concentration and discharge system for treating the wastewater from p-phenylenediamine production according to claim 1, wherein: A rotating shaft (401) is provided below the support bridge. The scraping device (402) is fixed below the rotating shaft (401), and the rotating shaft (401) is driven to rotate by a first rotating motor (4).

3. The sludge concentration and discharge system for treating the wastewater from phenylenediamine production according to claim 2, wherein: The rotating shaft (401) penetrates through the stirring container (302), and a stirrer (403) is fixed at one end of the rotating shaft (401) located inside the stirring container (302). A plurality of inclined mud scraping plates (4021) are provided below the scraping device (402).

4. A sludge concentration and discharge system for treating wastewater from phenylenediamine production according to claim 1, characterized in that: The sludge discharging mechanism includes a sludge discharge pump (203). The sludge inlet of the sludge discharge pump (203) is connected to the bottom end of the sludge hopper (202). A second rotating motor (204) is installed above the sludge discharge pump (203). Pulley wheels are installed on the power input shaft of the sludge discharge pump (203) and the output shaft of the second rotating motor (204), and the two pulley wheels are driven by a belt (205).

5. A sludge concentration and discharge system for treating wastewater from phenylenediamine production according to claim 1, characterized in that: A flow meter (303) is installed on the sewage inlet pipe (3). One end of the sewage inlet pipe (3) extends into the chemical dosing and mixing tank (5) and extends vertically and bends upward. The top end of the sewage inlet pipe (3) is rotatably connected to a distributor (7). A plurality of annular overflow plates (6) are rotatably installed in the chemical dosing and mixing tank (5) from top to bottom.

6. A sludge concentration and discharge system for treating wastewater from phenylenediamine production according to claim 5, characterized in that: A plurality of water outlet pipes (701) are arrayed around the distributor (7). The water outlet of the water outlet pipe (701) is aligned with the uppermost annular overflow plate (6). A horizontal section is provided at a section of the annular overflow plate (6) close to the inner wall of the annular overflow plate (6). One side of the annular overflow plate (6) away from the inner wall of the annular overflow plate (6) bends upward to form an overflow surface, and the inner diameters of the plurality of annular overflow plates (6) gradually decrease from top to bottom.

7. A sludge concentration and discharge system for treating the wastewater produced in the production of phenylenediamine according to claim 6, wherein: A flocculant introduction pipe (503) and a drive box (501) are provided at the top end of the chemical dosing and mixing tank (5). One end of the flocculant introduction pipe (503) extends into the drive box (501) and is connected to a rotating pipe (504) through a rotary joint (5031). The bottom end of the rotating pipe (504) extends into the chemical dosing and mixing tank (5) and is fixed to the top end of the distributor (7).

8. A sludge concentration and discharge system for treating the wastewater produced in the production of phenylenediamine according to claim 7, characterized in that: An annular connector (8) is rotatably mounted on the outside of the rotating pipe (504). A plurality of through holes (5042) are provided inside the rotating pipe (504) and located inside the annular connector (8). A plurality of flocculant discharge pipes (801) are mounted on the outside of the annular connector (8). One end of the flocculant discharge pipe (801) away from the annular connector (8) obliquely passes through the inner rings of the respective annular overflow trays (6) and is fixed to the bottom end of the lowermost annular overflow tray (6). The respective annular overflow trays (6) are fixed to each other by a connecting frame (601).

9. The sludge concentration and discharge system for treating the wastewater from p-phenylenediamine production according to claim 8, wherein: A plurality of atomizing nozzles (803) are equidistantly distributed at positions between adjacent annular overflow trays (6) on the outside of the flocculant discharge pipe (801).

10. A sludge concentration and discharge system for treating the wastewater from p-phenylenediamine production according to claim 9, characterized in that: A third rotating motor (502) is mounted on the top end of the drive box (501). The output shaft of the third rotating motor (502) extends into the drive box (501) and is fixed with a first gear (5021). A second gear (5041) is fixed on the outside of the rotating pipe (504). The first gear (5021) meshes with the second gear (5041). A toothed ring (802) is fixed between the top ends of the plurality of flocculant discharge pipes (801). The output shaft of the third rotating motor (502) extends into the chemical addition and mixing tank (5) and is fixed with a third gear (5022). The third gear (5022) meshes with the inner ring of the toothed ring (802). A plurality of flow-around components (505) are mounted on the inner wall of the chemical addition and mixing tank (5) at positions corresponding to the annular overflow trays (6).

Images