Special flocculation stirring device for magnetic coagulating sedimentation

Abstract

The invention discloses a special flocculation stirring device for magnetic coagulating sedimentation, and belongs to the technical field of sewage treatment. The stirring device comprises a guide cylinder arranged in the flocculation basin, and an axial-flow propeller stirrer and an anchor stirrer which are arranged on a stirring shaft, the axial-flow propeller stirrer is integrally arranged in the guide cylinder, 2-4 blades are arranged on the axial-flow propeller stirrer, and the axial-flow propeller stirrer is processed into a curved plate structure; the bending degree of two side edge areas, perpendicular to the stirring shaft, of the blades is greater than that of the middle areas of the blades; the anchor stirrer is arranged close to the bottom of the flocculation basin and has the same outline as the bottom of the flocculation basin; perforated gas distribution pipes are laid at the bottom of the flocculation basin. The stirring device can effectively improve the circulating effect of the flocculation basin, strengthen the combination of a flocculating agent, magnetic powder and pollutants, promote the floc to be more tightly adhered, greatly improve the flocculation efficiency of the flocculation basin, enable the magnetic floc with higher density to suspend and be not easy to precipitate and break, and have the advantages of reasonable design, good application effect and higher popularization value.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and more specifically relates to a special stirring device for flocculation of magnetic coagulation sedimentation. Background Art

[0002] The magnetic coagulation and sedimentation process adds magnetic material to the traditional coagulation and sedimentation process. Using coagulants and flocculants, pollutants in the water combine with magnetic particles to form magnetic flocs. The magnetic field and gravity are then used to accelerate the flocs' settling, thereby achieving water purification. The stirring step plays a crucial role in ensuring the sufficiency of the flocculation reaction and the uniform mixing of the magnetic material, flocculant, and pollutants.

[0003] There are many kinds of stirring devices on the market. However, in the flocculation process of magnetic coagulation sedimentation, traditional stirring devices generally have some limitations due to the characteristics of high density, poor fluidity and easy precipitation of magnetic powder flocs. On the one hand, the stirring method of ordinary stirring devices is relatively simple, and it is difficult to form a complex and uniform flow field in the reaction tank, so that the magnetic medium cannot fully contact and react with the flocculant and pollutants, resulting in the magnetic powder being deposited in the corners of the bottom of the tank and unable to form high-density magnetic flocs, affecting the subsequent sedimentation and separation links; on the other hand, there is a lack of optimized design for the characteristics of the magnetic coagulation sedimentation process. The shear force generated by some stirring devices is too large, which may damage the formed magnetic flocs and reduce the sedimentation efficiency.

[0004] After searching, the Chinese patent publication number is CN 205288274 U, the publication date is June 8, 2016, and the name of the invention is: A double stirring device for sewage treatment with an adjustable stirring range. The stirring device includes a shell, a stirring shaft is provided in the shell, the stirring shaft passes through the frame and is fixedly connected to the first motor located above the frame; a driven bevel gear is provided in the frame, the driven bevel gear is fixedly connected to the stirring shaft, and an active bevel gear is engaged next to the driven bevel gear, and the active bevel gear is fixedly connected to the second motor located on the left side of the frame through a rotating shaft. An air distribution pipe is provided at the bottom of the shell, and a number of air nozzles are evenly provided on the air distribution pipe. The air distribution pipe is connected to a high-pressure air source located outside the shell through an air pipe. This application improves the mixing effect of flocculant and sewage by providing a dual mixing and stirring device with stirring blades and air nozzles.

[0005] However, the stirring path of this stirring device is limited to linear vertical motion during use, lacking dynamic control capabilities in the horizontal dimension. This results in multiple blind mixing zones within the stirring vessel, directly impacting treatment efficiency. Most importantly, when used in coagulation processes involving magnetic materials, the axial flow generated by the impellers of this stirring device is insufficiently effective, making it difficult to overcome the gravitational settling characteristics of magnetic flocs. Consequently, in high-turbidity or complex water quality treatment scenarios, the flocs cannot be maintained in a stable suspended state.

[0006] In addition, although the stirring device also uses an air nozzle for blowing to improve the mixing and stirring effect, its air nozzle is fixedly installed vertically upward, which is easily blocked by suspended matter during long-term operation. In addition, maintenance requires shutdown and disassembly, which not only greatly increases maintenance costs and work intensity, but also poses a challenge to the reliability of continuous operation of the equipment. Summary of the Invention

[0007] The present invention aims to solve the limitations of traditional stirring devices in the magnetic coagulation and sedimentation process. More specifically, it solves the problem that magnetic flocs are difficult to form and the formed magnetic flocs are easily destroyed during the stirring process. A special stirring device for flocculation of magnetic coagulation and sedimentation is provided, which can solve the above problems, thereby improving the circulation effect of the flocculation tank and improving the mixing efficiency of the flocculation tank.

[0008] Technical Solution

[0009] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0010] The present invention provides a special stirring device for flocculation of magnetic coagulation sedimentation, comprising a guide tube arranged in a flocculation tank, a coaxially arranged axial flow propulsion stirrer and an anchor stirrer, wherein:

[0011] A frame and a matching base plate are set on the top of the flocculation tank to bear the entire gravity of the mixer; a stirring motor is set on the top of the frame, the stirring motor is connected to the reducer through a helical gear, and the reducer is connected to the stirring shaft through a rigid coupling and a double shaft diameter bearing.

[0012] An axial-flow propeller agitator is provided in the guide tube and fixedly mounted on the stirring shaft. The axial-flow propeller agitator is provided with 2 to 4 blades. Each blade is processed into a curved plate structure, and the curvature of the edge areas on both sides of the blade perpendicular to the stirring shaft is greater than that of the middle area of ​​the blade. Such a design can form a curvature streamlined guide surface, which conforms to the principle of fluid dynamics drag reduction, can promote the axial circulation of water flow and magnetic flocs in the guide tube, and reduce the energy consumption of the mixer.

[0013] The anchor agitator is arranged near the bottom of the flocculation tank and is installed at the bottom of the agitator shaft. By installing the axial flow propulsion agitator and the anchor agitator on the same agitator shaft, synchronous rotation is achieved, the binding force of the flocculant, magnetic powder and pollutants is enhanced, and the mixing efficiency of the flocculation tank is improved.

[0014] Preferably, the shape of the anchor wings on both sides of the anchor agitator is the same as the contour of the bottom of the flocculation tank, and can be precisely adapted to the contour of the bottom of the flocculation tank, and highly fit to form a contoured curved surface. Through the synergistic effect of the near-wall shear layer and the horseshoe vortex, the circulation power of the pool bottom is enhanced, the turbulence at the pool bottom is made strong, the water flow state at the pool bottom is improved, the solid particles at the bottom are washed away, and the bottom magnetic powder is prevented from settling and compacting due to the large gravity, thereby improving the suspension effect of the magnetic flocs.

[0015] In addition, the perforated air pipe is laid at the bottom of the flocculation tank and fixed to the bottom of the tank by a plastic pipe clamp. The perforated air pipe is connected to the air inlet main pipe, and the air inlet main pipe is connected to the air source device to supply air to the perforated air pipe. During long-term use, when the magnetic powder inevitably deposits at the bottom of the flocculation tank, air can be supplied through the perforated air supply pipe to drive the magnetic powder to float, promote full contact between the magnetic powder and pollutants, and thus form high-density magnetic flocs.

[0016] As a preferred embodiment of the present invention, the blades of the axial-flow propulsion agitator are designed to be irregularly shaped, which include a first region, a second region and a third region. The curved surface structure of the first region forms a primary guide surface, and the curved surface structures of the second region and the third region form a secondary guide surface. The curvature of the primary guide surface is smaller than the curvature of the secondary guide surface, which can effectively reduce the fluid desorption phenomenon at the tail of the blade, provide greater thrust, and further promote the axial circulation of water flow and magnetic flocs in the guide tube.

[0017] As a preferred embodiment of the present invention, the blade installation of the axial flow propulsion agitator is based on the principle of axial spiral twisting, adopts a downward pressure installation structure, and is detachably installed on the agitator shaft through a first connecting plate and bolts, thereby improving the convenience of blade installation.

[0018] More optimized, the angle formed between the blade and the axis of its installation shaft is 30°-60°, and the angle formed between two adjacent blades is 90°-180°. Combined with the design of the irregular structure of the blade, the synergistic effect of the centrifugal field and the axial lift field is integrated to generate a dual circulation driving force in the guide tube - the turbulent field in the axial zone strengthens the three-phase micro-mixing of magnetic powder, reagents and sewage, and the outer edge zone uses lift gradient flow to realize floc vector migration. Compared with the traditional stirring mode, the floc circulation efficiency is increased to more than 40%.

[0019] As a preferred embodiment of the present invention, the diameter of the axial-flow propeller agitator is denoted as Φd, and the equivalent diameter of the flocculation tank is denoted as D, where Φd = (0.3-0.53)D. The pitch S of the axial-flow propeller agitator is 1-2 times its diameter Φd. This configuration can generate more axial diversion, improve the turbulence of the water flow in the flocculation tank, enhance the axial circulation of the magnetic flocs, effectively increase the probability of collision and fusion between flocs, and promote the rapid growth and expansion of the magnetic flocs. In addition, the axial-flow propeller agitator is made of stainless steel or carbon steel with plastic lining, which increases its service life.

[0020] As a preferred embodiment of the present invention, air holes are evenly spaced along the circumference of the perforated air pipe (generally set at a spacing of 5-10 cm). The air holes include a first air hole and a second air hole. The aperture of the first air hole is larger than that of the second air hole. The air hole with a large aperture produces large bubbles with greater buoyancy, generating a greater disturbance force, driving the magnetic flocs to float; the air hole with a small aperture produces small bubbles with a large impact force, promoting the floating of the deposited magnetic flocs. Specifically, in the present invention, the aperture size of the first air hole is 3-5 mm, and the aperture size of the second air hole is 1-2 mm. By designing air holes of different aperture sizes, bubbles with different buoyancy and impact forces can be generated, forming a multi-level regular bubble tail flow, which is beneficial to enhancing the turbulence level at the bottom of the flocculation tank, driving the magnetic powder to float to further promote the contact between the magnetic powder and the pollutants. At the same time, the angles formed by the center lines of the first and second air holes and the horizontal plane are recorded as ∠α and ∠β respectively, ∠α=45-60°, ∠β=30-45°. By setting the angles of the air holes, the air holes of the cloth can be effectively prevented from being blocked by deposited flocs.

[0021] In addition, the perforated air duct of the present invention adopts intermittent air intake, which makes it difficult for flocs with higher density to settle, reduces energy consumption, and also effectively avoids the excessive air flow disturbance caused by continuous bubble impact, which leads to the breakage of large magnetic flocs.

[0022] As a preferred embodiment of the present invention, the anchor agitator is fixedly installed at the bottom of the agitator shaft through a second connecting plate, the outer diameter D2 of the anchor agitator is 0.9-0.95 times the equivalent diameter D of the flocculation tank, the width of the anchor wing is 50-400mm, the height of the anchor wing is 0.3-0.5 times the outer diameter D2 of the anchor agitator, and the anchor agitator is made of stainless steel or carbon steel lined with plastic.

[0023] As a preferred embodiment of the present invention, a wavy guide plate is installed on the inner wall of the guide tube. More specifically, the guide plate can be directly welded to the inner wall of the guide tube, and the angle c between the guide plate and the longitudinal axis of the guide tube is 0°-45°. By designing different installation angles, the overall vortex of the liquid can be effectively suppressed, and the tangential flow of the liquid can be converted into a composite axial and radial flow, which can significantly enhance the turbulent intensity of the liquid and improve the flocculation and stirring effect.

[0024] As a preferred embodiment of the present invention, the guide plates are provided in two groups, and the guide plates in each group are arranged at intervals along the circumference of the guide cylinder, wherein:

[0025] A group of guide plates are arranged along the upper part of the inner wall of the guide tube. The guide plates arranged along the upper part of the guide tube are flush with the top of the guide tube. This structural design is beneficial to improving the flow state of water inside the guide tube and near the water surface on the upper part, reducing the probability of short-circuiting from the upper part of the guide tube to the liquid surface and reducing the area of ​​dead water zone.

[0026] The other group is set along the lower part of the inner wall of the guide tube. The bottom of the guide plate is flush with the bottom of the guide tube. The interval between the upper and lower groups of guide plates is 1.0-1.2 times the overall height of the plug flow agitator to avoid affecting the stirring effect of the plug flow agitator.

[0027] The guide plate adopts a sinusoidal curved surface structure. The width of the guide plate is denoted as W, and the diameter of the guide tube is denoted as D1. W = (1 / 15 - 1 / 10) D1. The guide plate with a sinusoidal curved surface design can change the cross-sectional area of ​​the mainstream, reduce water flow resistance, enhance the disturbance of water near the wall, and improve the turbulent kinetic energy dissipation rate ε of the flocculation tank by more than 30%, thereby increasing the probability of floc collision and promoting floc growth.

[0028] As a preferred embodiment of the present invention, the guide tube is open at both ends, the upper end of which is a cylindrical structure, and the lower end expands outward to form a conical structure. The guide tube is fixed to the center of the flocculation tank by a supporting component. The overall height of the guide tube is recorded as H1, the effective water depth in the flocculation tank is recorded as H, H1 = (0.59-0.62) H, and the distance between the bottom of the guide tube and the bottom of the flocculation tank is recorded as h1, h1 = (0.8-1.0) Φd. The present invention optimizes the structure and installation position of the guide tube. When in use, the liquid inside and outside the guide tube flow in opposite directions, and the flow rate inside the tube is fast and the flow rate outside the tube is slow, forming an axial circulation around the guide tube. The guide tube and the axial flow propeller agitator work together to effectively suppress the "swirl" phenomenon caused by the rotation of the axial flow propeller agitator, reduce the lateral diversion of the fluid, allow the particles in the water to fully contact and collide to form larger flocs, prevent the magnetic flocs from settling and silting at the bottom of the tank, and at the same time reduce the energy consumption of the agitator.

[0029] As a preferred embodiment of the present invention, the diameter of the cylindrical structure is recorded as D1, the diameter of the axial flow propeller is recorded as Φd, D1 = (1.1-1.3)Φd, and the diffusion angle ∠b of the conical structure is 15-30°. This design can effectively converge the fluid and improve the flocculation efficiency.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The flocculation-specific stirring device for magnetic coagulation sedimentation provided by the present invention is designed with a single-shaft multi-paddle structure, an axial flow propulsion stirrer blade structure, an anchor stirrer structure, a wavy guide plate structure, and a perforated air distribution structure, wherein:

[0032] The design of one-axis multi-propeller structure can work synergistically at different levels and areas, greatly expanding the scope of stirring and improving the axial flow circulation effect of the flocculation tank;

[0033] The design of the axial flow propulsion agitator's blade structure and the anchor agitator structure helps to overcome the resistance of the water flow, enhances the guidance and pushing efficiency of the liquid, avoids the stirring dead corner, and the anchor agitator can effectively prevent the sedimentation of the magnetic flocs at the bottom, promotes the full mixing of the magnetic powder and flocs, and improves the stirring efficiency;

[0034] The design of the wavy guide plate structure can effectively eliminate the overall rotation of the liquid, change the mainstream cross-sectional area, increase the turbulence of the liquid, reduce the probability of short-circuiting on the liquid surface and reduce the area of ​​dead water, thus enhancing the uniformity and complexity of flocculation and stirring;

[0035] The perforated air distribution structure design can generate multi-layer regular bubble tail flow, enhance the water flow disturbance at the bottom of the pool, reduce the dead water area in the pool body, promote the floating of dense magnetic flocs and prevent them from settling, avoid the breakage of large magnetic flocs, and reduce system energy consumption.

[0036] The above-mentioned structural settings work together to enhance the lifting capacity of the stirring device, comprehensively optimize the circulation effect of the flocculation tank, and promote the efficient formation and stable suspension of magnetic flocs, thereby achieving more efficient and precise control and enhancement of the magnetic coagulation sedimentation flocculation process.

[0037] The device of the present invention has a reasonable structural design and can significantly improve the mixing efficiency of the flocculation tank, so that the magnetic flocs with heavier density are suspended and not easily precipitated and evenly dispersed in the water, effectively reducing the impact of shear force and avoiding the destruction of the formed magnetic flocs; at the same time, the stirring device makes full use of existing equipment, saves energy consumption, reduces operating costs, and has great promotion value in the field of sewage treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the three-dimensional structure of a special stirring device for flocculation of magnetic coagulation precipitation according to the present invention;

[0039] Figure 2 This is a schematic diagram of the main structure of the stirring device of the present invention after being installed in the flocculation tank (after being cut away);

[0040] Figure 3 Schematic diagram of the three-dimensional structure of the axial flow propulsion agitator of the present invention;

[0041] Figure 4 This is a schematic structural diagram of the axial flow propulsion agitator of the present invention in a top view;

[0042] Figure 5 This is a schematic diagram of the structure of a single blade of an axial flow propulsion agitator according to the present invention when viewed from above;

[0043] Figure 6 It is a structural schematic diagram of the anchor agitator of the present invention;

[0044] Figure 7 Schematic diagram of the structure of the guide plate of the present invention;

[0045] Figure 8 This is a schematic structural diagram of the perforated cloth air duct of the present invention;

[0046] Figure 9 Schematic diagram of the cross-sectional structure of the perforated air duct of the present invention;

[0047] Figure 10 Schematic diagram of the installation of the guide plate of the present invention.

[0048] In the picture;

[0049] 1. Stirring motor; 2. Helical gear reducer; 3. Frame; 4. Rigid coupling; 5. Base plate; 6. Air inlet pipe; 7. Flocculation tank; 8. Stirring shaft; 9. Guide plate; 10. Guide tube; 11. Upper support; 12. Lower support; 13. Axial-flow propeller agitator; 13-1. First area; 13-2. Second area; 13-3. Third area; 13-4. Threaded hole; 14. First connecting plate; 15. Anchor agitator; 16. Second connecting plate; 17. Perforated air distribution pipe; 18. Air distribution hole; 18-1. First air hole; 18-2. Second air hole; 19. Plastic pipe clamp; 20. Water inlet pipe; 21. Water outlet pipe. DETAILED DESCRIPTION

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed in the following specification.

[0051] It should be noted that, in the description of the present invention, the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0052] At the same time, in the description of the present invention, unless otherwise clearly stipulated and limited, the terms "install", "set", "connect", "fix", "screw" and so on should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0053] Furthermore, it should be understood that for the sake of ease of description, the sizes of the various components shown in the drawings are not drawn according to actual proportions. For example, the thickness or width of certain layers may be exaggerated relative to other layers.

[0054] The present invention will be further described below with reference to specific embodiments.

[0055] Example 1

[0056] like Figure 1 and Figure 2 As shown, a flocculation-specific stirring device for magnetic coagulation sedimentation in this embodiment includes a stirring motor 1, a helical gear reducer 2, a rigid coupling 4, a frame 3, a stirring shaft 8 and a guide tube 10. The guide tube 10 is installed in the flocculation tank 7. The frame 3 and the matching base plate 5 are set on the top of the flocculation tank 7 to bear the entire gravity of the stirrer. The stirring motor 1 is set at the top of the frame 3. The stirring motor 1 is connected to the reducer 2 through a helical gear. The reducer 2 is connected to the stirring shaft 8 through a rigid coupling 4 and a double shaft diameter bearing. The stirring shaft 8 is driven by the stirring motor 1 to provide power for the stirring device. An axial flow propulsion stirrer 13 and an anchor stirrer 15 are set on the stirring shaft 8, wherein the axial flow propulsion stirrer 13 is arranged inside the guide tube 10, and the outer wall of the guide tube 10 is fixed to the center of the flocculation tank 7 through an upper support 11 and a lower support 12.

[0057] In this embodiment, the sewage inlet pipe 20 of the flocculation tank 7 is located at the bottom of one side wall of the flocculation tank 7, and the outlet pipe 21 is located at the upper portion of the other side wall of the flocculation tank 7. Sewage enters the flocculation tank 7 through the inlet pipe 20. Based on the sewage treatment volume, appropriate concentrations of flocculant and magnetic powder are added to the flocculation tank 7. The flocculant and magnetic powder react with the pollutants in the sewage to form magnetic flocs. Simultaneously, the stirring motor 1 drives the stirring shaft 8, causing the axial propeller agitator 13 and the anchor agitator 15 to rotate synchronously, enhancing the binding force between the flocculant, magnetic powder, and pollutants, and improving the mixing efficiency of the flocculation tank. The treated sewage is discharged through the outlet pipe 21.

[0058] In order to better promote the axial circulation in the flocculation tank 7, prolong the residence time of the sewage in the flocculation tank 7, obtain a larger flow rate and circulation volume, and improve the stirring efficiency, an axial flow propulsion stirrer 13 is installed in the middle and upper parts of the stirring shaft 8. Figure 2-5 As shown, the axial flow propulsion stirrer 13 is installed in a downward pressure manner (ie, after installation, as shown in FIG. Figure 3 As shown, all the blades tend to converge downwards) at the upper part of the guide tube 10, the axial flow propulsion agitator 13 is composed of three irregular blades, the angle between two adjacent blades is 120 degrees, and each blade is composed of three parts, specifically the first area 13-1, the second area 13-2 and the third area 13-3. The first area 13-1 is provided with multiple groups of threaded holes 13-4 near the root of the blade, which are fixed by bolts and the first connecting plate 14, so that the blade is installed on the stirring shaft 8. The entire blade is designed as a curved plate structure, which is hydraulically formed in one piece using existing hydraulic equipment, and the curved surface structure of the first area 13-1 forms a primary guide surface, which is convenient for introducing water flow into the stirring device. The curved surface structures of the second area 13-2 and the third area 13-3 form secondary guide surfaces, and the curvature of the primary guide surface is smaller than that of the secondary guide surface, which can not only effectively promote the axial circulation of water flow and magnetic flocs in the guide tube 10, but also reduce the energy consumption of the stirring device.

[0059] The blades are made of 304 stainless steel, offering excellent corrosion resistance and mechanical strength. The three blades are installed using a downward pressure mechanism, with the angle ∠a between the blades and the agitator shaft 8 designed to be 60°. The diameter Φd of the axial-flow propeller agitator 13 is designed to be 0.45 times the equivalent diameter D of the flocculation tank 7, and the pitch S is 1 times the diameter d. This design generates more axial flow diversion, improves the turbulence of the water flow in the flocculation tank, enhances the axial circulation of the magnetic flocs, effectively increases the probability of collision and fusion between flocs, and promotes the rapid growth of the magnetic flocs.

[0060] In this embodiment, the paddle structure and mounting method are optimized, integrating the synergistic effects of the centrifugal field and the axial lift field. This generates a dual circulation driving force within the guide tube: a turbulent flow field in the central zone enhances the three-phase micro-mixing of magnetic powder, reagent, and wastewater, while a lift gradient flow in the outer zone achieves vectorial migration of flocs. As wastewater circulates within the flocculation tank 7, the upward-lifting axial-flow push-flow agitator 13 rotates, adapting to the dynamic changes in the fluid and flocs. The paddle's streamlined guide surfaces of varying curvatures maximize the ability to overcome water resistance, provide greater downward thrust, and enhance the efficiency of guiding and pushing the liquid. The sewage is sucked in from the top of the guide tube 10, accelerated and pressed down by the blades of the axial flow plug flow agitator 13, and diffused out from the bottom of the guide tube 10 to the surrounding areas. Then, with the help of the impact force of the water flow on the bottom of the pool, the magnetic flocs at the bottom of the flocculation tank 7 are driven to flow from the annular gap area of ​​the pool body from bottom to top. After part of the water flow passes over the upper guide plate 9, it re-enters the top of the guide tube 10 to form a closed vertical circulation loop, and part of the water flow is discharged from the outlet pipe 21.

[0061] More optimized, such as Figure 6 As shown, in order to further enhance the bottom circulation power, improve the magnetic flocculent suspension effect, prevent the magnetic powder from accumulating at the bottom of the flocculation tank 7, and achieve the best use effect, an anchor agitator 15 is provided near the bottom of the flocculation tank 7. The anchor agitator 15 is fixedly mounted on the bottom of the agitator shaft 8 via a second connecting plate 16. The anchor wings on both sides of the anchor agitator 15 have the same shape as the bottom contour of the flocculation tank 7, and can be precisely adapted to the bottom contour of the flocculation tank, and are highly fitted to form a contoured curved surface. Through the synergistic effect of the near-wall shear layer and the horseshoe vortex, the bottom circulation power is enhanced, the turbulence at the bottom of the pool is strong, the water flow state at the bottom of the pool is improved, the solid particles at the bottom are washed away, and the bottom magnetic powder is prevented from settling and compacting due to the large gravity, thereby improving the magnetic flocculent suspension effect.

[0062] Furthermore, the anchor agitator 15 of this embodiment is also made of corrosion-resistant 304 stainless steel. The outer diameter D2 of its anchor wings is 0.95 times the equivalent diameter D of the flocculation tank 7, and the width t of the anchor wings is set to 100 mm. When sewage circulates to the tank bottom, the agitator shaft 8 drives the anchor agitator 15 and the axial-flow propeller agitator 13 to rotate synchronously, promoting thorough mixing of the magnetic powder and flocs, improving the water flow at the tank bottom, and preventing the accumulation of magnetic powder and the breakup of already formed flocs.

[0063] As a further improvement of this embodiment, in order to avoid inertial water flow and eliminate the "swirl" phenomenon, the guide tube 10 of this embodiment is open at both ends, the upper end of which is a cylindrical structure, and the lower end expands outward to form a conical structure. The overall height of the guide tube 10 is recorded as H1, the effective water depth in the flocculation tank 7 is recorded as H, H1 = 0.6H, and the distance h1 from the bottom of the guide tube 10 to the bottom of the tank is set to 0.8 times the diameter of the axial flow propulsion agitator 13, that is: h1 = 0.8Φd, the guide tube 1 The diameter D1 of the upper cylinder is set to 1.1 times the diameter of the axial-flow propulsion agitator 13, that is, D1 = 1.1Φd. The diffusion angle ∠b of the conical structure is 30°. When the sewage flows into the flocculation tank 7, it is blocked by the guide tube 10. In combination with the axial propulsion of the axial-flow propulsion agitator 13 and the anchor agitator 15, the tangential flow and vortex flow of the water body are restricted, forming a complex water flow pattern that crosses vertically and horizontally, thereby improving the flocculation efficiency and reducing the energy consumption of the stirring motor 1.

[0064] Reference Figure 2 and Figure 8 In order to better reduce the deposition of magnetic powder, in this embodiment, a perforated air pipe 17 is laid in a circular shape at the bottom of the flocculation tank 7. The perforated air pipe 17 is connected to the external air source through the air inlet pipe 6. The air inlet pipe 6 is arranged along the wall of the flocculation tank 7, and can reduce the deposition of magnetic powder by supplying air into the flocculation tank 7.

[0065] In addition, more optimized, refer to Figure 1-2 A guide plate 9 is also installed on the inner wall of the guide tube 10 by welding. The design of the guide plate 9 can effectively eliminate the overall rotation of the liquid, transform the tangential flow of the liquid into a composite flow of axial and radial directions, significantly enhance the turbulent intensity of the liquid, and improve the flocculation and stirring effect.

[0066] As a more optimized design of the guide plate 9, two layers of guide plates 9 can be set in the guide tube 10, and each layer of guide plates 9 is arranged at intervals along the circumference of the guide tube 10. In this embodiment, four guide plates 9 are provided on each layer, and the four guide plates 9 are arranged symmetrically around the center of the stirring shaft 8. The angle between each guide plate 9 and the longitudinal axis of the guide tube 10 is 0°.

[0067] Another layer of guide plates 9 is installed along the lower inner wall of the guide tube 10, flush with the bottom of the cylindrical portion of the guide tube 10. The distance between the upper and lower guide plates 9 is set to 1.2 times the vertical height of the propeller agitator 13 to avoid obstructing the operation of the high-efficiency axial flow agitator 13. The width W of the guide plates 9 is set to 1 / 12 of the diameter D1 of the guide tube 10, further eliminating overall liquid rotation, reducing the dead water area in the flocculation tank 7, changing the main flow cross-sectional area, reducing water flow resistance, and enhancing the agitation efficiency of the flocculation tank 7.

[0068] Example 2

[0069] like Figure 7 As shown, the present embodiment is a flocculation-specific stirring device for magnetic coagulation precipitation, and its structure is basically the same as that of embodiment 1. The difference between it and embodiment 1 is that the guide plate 9 is processed into a wavy structure. Specifically, as shown in FIG. Figure 10 As shown, in this embodiment, a wavy guide plate 9 is mounted on the inner wall of the guide tube 10. The included angle c between the guide plate 9 and the longitudinal axis of the guide tube 10 is 30°. The guide plate 9 adopts a sinusoidal curved surface structure, which can change the cross-sectional area of ​​the main flow, reduce water flow resistance, enhance the disturbance of the water near the wall, and improve the turbulent kinetic energy dissipation rate ε of the flocculation tank by more than 30%, thereby increasing the probability of floc collision and promoting floc growth.

[0070] More optimally, the wavy guide plate 9 and the longitudinal axis of the guide tube 10 are installed at an angle ∠c of 30°, which is conducive to converting the weakening of the tangential force into a strong downward thrust along the axis, guiding and accelerating the axial circulation of the liquid, and conforming to the dynamic characteristics of the fluid, which is conducive to reducing the energy loss caused by fluid impact and friction, and extending the service life of the guide plate 9 and the guide tube 10.

[0071] Example 3

[0072] The present embodiment is a special stirring device for flocculation of magnetic coagulation precipitation, and its structure is mainly the same as that of embodiment 1. The difference between the present embodiment and embodiment 1 is that: Figure 8 and Figure 9 Air distribution holes 18 are evenly spaced along the circumferential direction of the perforated air distribution pipe 17. The air distribution holes 18 include a first air hole 18-1 and a second air hole 18-2. The aperture of the first air hole 18-1 is larger than that of the second air hole 18-2. The air holes with large apertures produce large bubbles with greater buoyancy, which generate greater disturbance force and drive the magnetic flocs to float up; the air holes with small apertures produce small bubbles with large impact force and promote the floating of the deposited magnetic flocs. Specifically, in the present invention, the aperture size of the first air hole 18-1 is 5mm, and the aperture size of the second air hole 18-2 is 1mm. By designing air holes with different aperture sizes, bubbles with different buoyancy and impact force can be generated to form a multi-level regular bubble tail flow, which is beneficial to enhance the turbulence level at the bottom of the flocculation tank, drive the magnetic powder to float to further promote the contact between the magnetic powder and the pollutants, and facilitate the formation of high-density magnetic flocs.

[0073] More optimized, such as Figure 9 As shown, the spacing between the air holes 18 in this embodiment is 5 cm (the distance between the two first air holes 18-1 is used as the standard in this embodiment), and the angles formed by the center lines of the first air holes 18-1 and the second air holes 18-2 and the horizontal plane are respectively recorded as ∠α and ∠β, where ∠α=45°, ∠β=30°. By setting the angles of the air holes, it is possible to effectively avoid the deposition of flocs blocking the air holes.

[0074] More optimized, the perforated air pipe 17 adopts intermittent air intake. By adopting indirect air supply, it makes it difficult for flocs with higher density to settle, reducing energy consumption. At the same time, it also effectively avoids the excessive air flow disturbance caused by continuous bubble impact, which leads to the breakage of large magnetic flocs. In addition, intermittent air supply can also reduce the energy consumption of the air supply device and the stirring motor 1 to a certain extent, which is more conducive to achieving the goal of efficient and environmentally friendly sewage treatment.

[0075] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A special stirring device for flocculation of magnetic coagulation sedimentation, comprising a guide tube (10), characterized in that: The invention also comprises an axial flow propulsion stirrer (13) and an anchor stirrer (15) arranged coaxially, wherein: The draft tube (10) is arranged in the flocculation tank (7), and an axial flow propulsion agitator (13) is arranged in the draft tube (10); The axial flow propulsion stirrer (13) is provided with 2 to 4 blades, each blade is processed into a curved plate structure, and the curvature of the edge areas on both sides of the blade perpendicular to the stirring shaft (8) is greater than that of the middle area of ​​the blade; There is a continuous angle gradient change from 0° to 15° between its axis and its outer edge and the horizontal plane; The anchor stirrer (15) is close to the bottom of the flocculation tank (7), and the anchor wings on both sides of the anchor stirrer (15) have the same shape as the bottom contour of the flocculation tank (7); The axial flow propulsion stirrer (13) and the anchor stirrer (15) are both mounted on the stirring shaft (8), and the stirring shaft (8) is connected to an external driving device; The perforated air distribution pipe (17) is laid at the bottom of the flocculation tank (7), and the perforated air distribution pipe (17) is communicated with the air inlet main pipe (6).

2. The flocculation-specific stirring device for magnetic coagulation precipitation according to claim 1, characterized in that: The blades of the axial flow propulsion agitator (13) are processed into an irregular shape, which includes a first area (13-1), a second area (13-2) and a third area (13-3). The curved surface structure of the first area (13-1) forms a primary guide surface, and the curved surface structures of the second area (13-2) and the third area (13-3) form a secondary guide surface, and the curvature of the primary guide surface is smaller than the curvature of the secondary guide surface.

3. The flocculation-specific stirring device for magnetic coagulation precipitation according to claim 2, characterized in that: The angle formed between the blades of the axial flow propulsion stirrer (13) and the axis of the shaft on which it is installed is 30°-60°, and the angle formed between two adjacent blades is 90°-180°.

4. The flocculation-specific stirring device for magnetic coagulation precipitation according to claim 1, characterized in that: The diameter of the axial flow propulsion stirrer (13) is denoted as Φd, the equivalent diameter of the flocculation tank (7) is denoted as D, Φd=(0.3-0.53)D, the pitch S of the axial flow propulsion stirrer (13) is 1-2 times of its diameter Φd, and the axial flow propulsion stirrer (13) is made of stainless steel or carbon steel lined with plastic material.

5. A flocculation-specific stirring device for magnetic coagulation precipitation according to any one of claims 1 to 4, characterized in that: Air distribution holes (18) are evenly spaced along the circumferential direction of the perforated air distribution pipe (17). The air distribution holes (18) include a first air hole (18-1) and a second air hole (18-2). The aperture of the first air hole (18-1) is larger than that of the second air hole (18-2). The perforated air distribution pipe (17) adopts intermittent air intake.

6. A flocculation-specific stirring device for magnetic coagulation precipitation according to any one of claims 1 to 4, characterized in that: The anchor stirrer (15) is fixedly mounted on the bottom of the stirring shaft (8) via a second connecting plate (16). The outer diameter D2 of the anchor stirrer (15) is 0.9-0.95 times the equivalent diameter D of the flocculation tank (7). The width of the anchor wing is 50-400 mm. The anchor stirrer (15) is made of stainless steel or carbon steel with plastic lining.

7. A flocculation-specific stirring device for magnetic coagulation precipitation according to any one of claims 1 to 4, characterized in that: A wave-shaped guide plate (9) is installed on the inner side wall of the guide tube (10), and an angle c between the guide plate (9) and the longitudinal axis of the guide tube (10) is 0°-45°.

8. The flocculation-specific stirring device for magnetic coagulation precipitation according to claim 7, characterized in that: The guide plates (9) are arranged in two groups, and the guide plates (9) in each group are arranged at intervals along the circumference of the guide tube (10), wherein: A group of guide plates (9) are arranged along the upper portion of the inner side wall of the guide tube (10), and the guide plates (9) arranged along the upper portion of the guide tube (10) are flush with the top of the guide tube (10); The other group is arranged along the lower portion of the inner wall of the guide tube (10), and the interval between the upper and lower groups of guide plates (9) is 1.0-1.2 times the overall height of the plug-flow agitator (13); The guide plate (9) adopts a sinusoidal curved surface structure, the width of the guide plate (9) is recorded as W, the diameter of the guide tube (10) is recorded as D1, and W=(1 / 15-1 / 10)D1.

9. A special stirring device for flocculation of magnetic coagulation sedimentation according to any one of claims 1 to 4, characterized in that: The guide tube (10) is open at both ends, the upper end of which is a cylindrical structure, and the lower end of which expands outward to form a conical structure. The guide tube (10) is fixed to the center of the flocculation tank (7) through a supporting component. The overall height of the guide tube (10) is recorded as H1, and the effective water depth in the flocculation tank (7) is recorded as H, where H1=(0.59-0.62)H.

10. The flocculation-specific stirring device for magnetic coagulation sedimentation according to claim 9, characterized in that: The diameter of the cylindrical structure is recorded as D1, the diameter of the axial flow propulsion stirrer (13) is recorded as Φd, D1 = (1.1-1.3) Φd, and the diffusion angle ∠b of the conical structure is 15-30°.

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