A dosing device for wastewater treatment

Abstract

This invention relates to the field of wastewater treatment technology, specifically to a dosing device for wastewater treatment, comprising a mixing unit and a driving unit. The mixing unit includes a mixing pipe and multiple spiral blades installed inside the mixing pipe, the spiral blades being rotatable relative to the mixing pipe; the driving unit drives fluid to flow through the mixing pipe. The mixing unit can automatically switch between a first operating mode and a second operating mode based on the fluid flow rate. When the fluid is at a normal flow rate, the mixing unit is in the first operating mode, and the spiral blades remain stationary relative to the mixing pipe, uniformly mixing the concentrated reagent and dilution water. When the fluid flows through the mixing pipe at a high speed in a pulsed pattern, the mixing unit switches to the second operating mode, the driving force of the fluid causing the spiral blades to rotate, thereby dynamically scraping the inner wall of the mixing pipe against the outer wall of the spiral blades, effectively removing reagent residue from the inner wall of the mixing pipe, achieving automatic cleaning.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a dosing device for wastewater treatment. Background Technology

[0002] A pipeline static mixer is a high-efficiency fluid mixing device with no moving parts. It consists of a pipe body and a built-in fixed mixing unit, and is widely used in wastewater treatment, primarily for the online continuous dilution and homogenization of concentrated chemicals. In use, the pipeline static mixer is connected in series to the material conveying pipeline via flanges or threads. No external driving power is required; the concentrated chemical and dilution water enter the pipe body under its own conveying pressure. The mixing unit then separates, shears, rotates, and re-combines the solutions to obtain a stable concentration of diluted solution, providing a homogeneous chemical system for subsequent water treatment.

[0003] However, when concentrated chemicals pass through the static mixer in the pipeline, some chemicals have high viscosity and strong adhesion, and others easily react chemically with water to form insoluble deposits. These substances adhere to and deposit on the inner wall of the pipe and the structural surface of the internal mixing unit, making them difficult to remove completely by conventional water flushing. After prolonged operation, residual chemicals and scale accumulate and harden, not only reducing the effective flow area of ​​the mixing unit and increasing fluid resistance, but also weakening the dilution and mixing effect of the chemicals, and even causing local blockage of the flow channels within the pipe, affecting the stable operation of subsequent wastewater treatment processes. Summary of the Invention

[0004] Therefore, it is necessary to provide a dosing device for wastewater treatment to address the problem of difficult-to-clean chemicals and scale adhering to the inner wall of the pipe and the surface of the mixing unit structure in current pipeline static mixers.

[0005] The above objectives are achieved through the following technical solutions: A dosing device for wastewater treatment, comprising: A mixing unit includes a mixing pipe and multiple helical blades; the multiple helical blades are rotatably installed inside the mixing pipe along the axial direction of the mixing pipe, and the helical directions of two adjacent helical blades are opposite; the outer walls of the multiple helical blades are in contact with the inner wall of the mixing pipe.

[0006] A drive unit for driving multiple fluids to flow through the mixing pipe.

[0007] The mixing unit has a first working mode and a second working mode, and can switch between the first working mode and the second working mode according to the flow rate of the fluid flowing through the mixing pipe. When the mixing unit is in the first working mode, the plurality of spiral blades are stationary relative to the mixing pipe to mix the various fluids flowing through it. When the mixing unit is in the second working mode, two adjacent spiral blades rotate relative to each other in opposite directions under the drive of the fluid.

[0008] Furthermore, the mixing unit also includes a central shaft and a limiting structure. The central shaft is coaxially fixedly installed inside the mixing pipe, and the plurality of spiral blades are rotatably sleeved on the central shaft. The limiting structure is used to restrict the rotation of the plurality of spiral blades relative to the central shaft when the mixing unit is in the first working mode, and to release the rotation restriction on the plurality of spiral blades when the mixing unit is in the second working mode.

[0009] Furthermore, the limiting structure includes a limiting protrusion, a limiting groove, and a rotating groove; multiple limiting protrusions are provided, and the multiple limiting protrusions are fixedly disposed on the outer wall of the central shaft, with each limiting protrusion corresponding to one of the spiral blades; the inner wall of each spiral blade is provided with a limiting groove and a rotating groove, and the limiting groove and the rotating groove are connected along the axial direction of the central shaft.

[0010] When the mixing unit is in the first working mode, the limiting protrusion is fully embedded in the limiting groove; when the mixing unit is in the second working mode, the limiting protrusion is fully embedded in the rotating groove.

[0011] Furthermore, the mixing unit also includes a first elastic element disposed between one of the spiral blades and the mixing pipe, and the elastic force of the first elastic element always keeps the limiting protrusion located in the limiting groove.

[0012] Furthermore, the mixing unit also includes a flexible layer and an expansion structure; the surface of each of the helical blades is covered with the flexible layer, which is capable of deformation; the expansion structure is used to drive the flexible layer to deform when the mixing unit is in the second operating mode.

[0013] Furthermore, the expansion structure includes a first flow channel, which is disposed inside the spiral blade, and the surface of the spiral blade is provided with a water passage hole communicating with the first flow channel.

[0014] When the mixing unit is in the first operating mode, the flexible layer blocks the water passage; when the mixing unit is in the second operating mode, fluid enters the first flow channel and flows out from the water passage to drive the flexible layer to bulge and deform.

[0015] Furthermore, a central flow channel is provided inside the central shaft, which is connected to the first flow channel inside the spiral blade, for conveying fluid to the first flow channel in the second working mode.

[0016] Furthermore, the surface of the flexible layer is coated with polytetrafluoroethylene.

[0017] Furthermore, the mixing unit also includes a retaining ring, which is detachably and fixedly connected to the mixing pipe via threads; a limiting rod extends radially from the central shaft, and the retaining ring is provided with a retaining groove that cooperates with the limiting rod. The limiting rod is embedded in the retaining groove to restrict the axial movement of the central shaft relative to the mixing pipe.

[0018] Furthermore, the axial end faces of the spiral blade are provided with guide slopes, which are inclined along the flow direction of the fluid.

[0019] The beneficial effects of this invention are: This invention provides a dosing device for wastewater treatment, comprising a mixing unit and a driving unit. The mixing unit includes a mixing pipe and multiple helical blades disposed inside the mixing pipe, the helical blades being rotatable relative to the mixing pipe; the driving unit is used to drive concentrated reagent and dilution water to flow stably through the mixing pipe. The mixing unit has a first operating mode and a second operating mode, and the mixing unit can automatically switch between the first operating mode and the second operating mode according to the fluid flow rate.

[0020] When the fluid flows through the mixing pipe at a normal flow rate, the mixing unit is in its first operating mode. At this time, multiple spiral blades remain stationary relative to the mixing pipe. The stationary spiral blades continuously divert, shear, and merge the flowing concentrated reagent and dilution water, achieving thorough and uniform mixing of two or more fluids and meeting the process requirements for wastewater treatment dosing.

[0021] When the drive unit increases the fluid velocity in a pulsed manner, causing the fluid to flow at high speed through the mixing pipe, the mixing unit automatically switches to the second working mode. The high-speed fluid flow drives the spiral blades, causing the spiral blades to rotate. In the rotating state, the outer wall of the spiral blades forms a dynamic scraping action with the inner wall of the mixing pipe, effectively removing residual chemicals, scale, and impurities adhering to the inner wall of the mixing pipe. This automatic cleaning of the inner wall of the mixing pipe and the surface of the spiral blades is completed without disassembling the equipment, effectively reducing the risk of blockage, improving the stability of equipment operation, and extending service life. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a dosing device for wastewater treatment provided in an embodiment of the present invention; Figure 2 for Figure 1 A schematic diagram of a chemical dosing device used for wastewater treatment. The casing is omitted from the diagram for easier observation. Figure 3 This is a schematic diagram of the structure of a mixing unit in a dosing device for wastewater treatment provided in an embodiment of the present invention; Figure 4 for Figure 3 The front view of the structure shown; Figure 5 for Figure 4 A cross-sectional view along the AA direction; Figure 6 for Figure 5 A magnified view of a section at point B in the middle; Figure 7 An exploded view of a mixing unit in a dosing device for wastewater treatment provided in an embodiment of the present invention; Figure 8 for Figure 7 A schematic diagram of the spiral blades in the structure shown; Figure 9 for Figure 7 The diagram shows the structure of the spiral blades, with the flexible layer omitted for easier observation. Figure 10 for Figure 8 Top view of the structure shown; Figure 11 for Figure 10 A cross-sectional view along the CC direction; Figure 12 for Figure 10 A cross-sectional view along the DD direction.

[0023] in: 110. Housing; 120. Suction pipe; 121. First metering pump; 130. Drug suction pipe; 131. Second metering pump; 140. Nozzle; 210. Mixing pipe; 220. Spiral blade; 221. Limiting groove; 222. Rotating groove; 223. Flexible layer; 224. Sealing strip; 225. First flow channel; 226. Water passage hole; 227. Flow guide slope; 230. Central shaft; 231. Limiting rod; 232. Limiting protrusion; 233. Central flow channel; 234. Connecting hole; 240. First compression spring; 250. Snap ring. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0025] The component designations used in this document, such as "first" and "second," are merely for distinguishing the described objects and do not have any sequential or technical meaning. The terms "connection" and "linkage" used in this invention, unless otherwise specified, include both direct and indirect connections (linkages). It should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0026] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0027] The following reference Figures 1 to 12 The present invention describes a dosing device for wastewater treatment, comprising a housing 110, a mixing unit, and a driving unit.

[0028] Specifically, the housing 110 is a closed box structure, which provides a stable mounting base for other components of the wastewater treatment dosing equipment.

[0029] The mixing unit includes a mixing pipe 210 and multiple spiral blades 220.

[0030] The mixing pipe 210 is a through-type tubular structure, fixedly connected to the shell 110. The mixing pipe 210 provides a closed flow channel space for mixing the concentrated reagent and dilution water. The inlet end of the mixing pipe 210 is provided with a water inlet and a reagent inlet. The water inlet is used to enable the directional flow of dilution water, and the reagent inlet is used to enable the directional flow of concentrated reagent.

[0031] Multiple helical blades 220 are coaxially mounted inside the mixing pipe 210 along its axial direction, with the outer wall of the helical blades 220 fitting against the inner wall of the mixing pipe 210. The helical directions of adjacent helical blades 220 are opposite, and the edges of adjacent helical blades 220 that abut against each other are arranged perpendicularly to ensure that the fluid flowing through the mixing pipe 210 is continuously split, sheared, and merged, achieving thorough homogeneous mixing of the concentrated reagent and the dilution water.

[0032] The drive unit includes a water suction pipe 120, a first metering pump 121, a medicine suction pipe 130, a second metering pump 131, and a nozzle 140.

[0033] One end of the suction pipe 120 is connected to an external dilution water storage device, and the other end of the suction pipe 120 is connected to the inlet of the mixing pipe 210. The suction pipe 120 is used to transport dilution water. The first metering pump 121 is fixedly installed inside the housing 110 and connected in series to the section of the suction pipe 120. The first metering pump 121 is used to accurately measure and stably transport the dilution water flow rate, ensuring a constant and controllable supply of dilution water.

[0034] One end of the suction tube 130 is connected to an external concentrated drug storage device, and the other end is connected to the inlet of the mixing pipe 210. The suction tube 130 is used to achieve directional delivery of the concentrated drug. The second metering pump 131 is fixedly installed inside the housing 110 and connected in series with the section of the suction tube 130. The second metering pump 131 is used to achieve precise metering and stable control of the concentrated drug dosage, ensuring a constant and accurate concentrated drug dosage ratio.

[0035] The nozzle 140 is fixedly connected to the outlet end of the mixing pipe 210. The nozzle 140 is used to spray the mixed reagent dilution in a uniformly dispersed state to achieve full contact between the reagent dilution and the wastewater to be treated, thereby ensuring the efficient operation of the wastewater treatment reaction.

[0036] To clean the residual concentrated agent on the inner wall of the mixing pipe 210 and the surface of the spiral blade 220, the mixing unit also includes two retaining rings 250, a central shaft 230, a limiting structure, and a first elastic element.

[0037] Specifically, the retaining ring 250 has a ring-shaped structure and external threads are machined on its outer wall. The two retaining rings 250 are located at both ends of the mixing pipe 210, and both retaining rings 250 are detachably fixed to the inner wall of the mixing pipe 210 through threaded engagement. The retaining rings 250 are used to provide axial limiting support for the central shaft 230.

[0038] The central shaft 230 is a cylindrical shaft structure. Limiting rods 231 extend radially from the outer walls of both ends of the central shaft 230. A retaining ring 250 has a groove that matches the limiting rod 231. The limiting rod 231 at one end of the central shaft 230 is embedded in the groove of the retaining ring 250 to limit the axial displacement and circumferential rotation of the central shaft 230 relative to the mixing pipe 210, ensuring that the central shaft 230 and the mixing pipe 210 remain coaxially and stably connected. Multiple helical blades 220 are coaxially sleeved on the outside of the central shaft 230, forming a sliding fit with the central shaft 230. The multiple helical blades 220 can reciprocate along the axial direction of the central shaft 230. The retaining rings 250 at both ends of the central shaft 230 limit the axial sliding stroke of the multiple helical blades 220, effectively preventing the multiple helical blades 220 from dislodging from the central shaft 230 and the mixing pipe 210 during movement.

[0039] The limiting structure includes a limiting protrusion 232, a limiting groove 221, and a rotating groove 222. Multiple limiting protrusions 232 are provided, fixedly mounted on the outer wall surface of the central shaft 230, and each limiting protrusion 232 corresponds to a spiral blade 220. Each spiral blade 220 has a limiting groove 221 and a rotating groove 222 on its inner wall, with the limiting groove 221 and rotating groove 222 communicating with each other along the axial direction of the central shaft 230. The limiting protrusion 232 can be completely embedded inside the limiting groove 221 or the rotating groove 222, and can move axially relative to the limiting groove 221 and the rotating groove 222. The limiting protrusion 232 can rotate freely circumferentially within the rotating groove 222.

[0040] The first elastic element is a first compression spring 240. The first compression spring 240 is disposed between the spiral blade 220 near the outlet end of the mixing pipe 210 and the inner wall end face of the mixing pipe 210. One end of the first compression spring 240 abuts against the corresponding spiral blade 220, and the other end of the first compression spring 240 abuts against the inner wall of the mixing pipe 210. The first compression spring 240 continuously provides a constant axial elastic force to drive the multiple spiral blades 220 as a whole to always move along the axis of the central shaft 230 toward the inlet end of the mixing pipe 210, thereby ensuring that the limiting protrusion 232 on the central shaft 230 can be stably held inside the limiting groove 221 on the inner wall of the spiral blade 220, realizing reliable locking of the circumferential rotation of the spiral blade 220.

[0041] The hybrid unit has a first operating mode and a second operating mode.

[0042] When the mixing unit is in the first working mode, the axial elastic force of the first compression spring 240 drives the multiple spiral blades 220 to remain in the initial position close to the water inlet end of the mixing pipe 210. Each limiting protrusion 232 on the central shaft 230 is completely located inside the limiting groove 221 on the inner wall of a spiral blade 220, so as to completely restrict the circumferential rotation of the spiral blades 220 relative to the central shaft 230, and keep the multiple spiral blades 220 in a static and fixed state relative to the central shaft 230 and the mixing pipe 210. At this time, the first metering pump 121 continuously delivers dilution water into the mixing pipe 210 according to the preset flow rate, and the second metering pump 131 delivers concentrated agent into the mixing pipe 210 according to the preset ratio. The two metering systems adjust the dosage of concentrated agent and dilution water in real time according to the set agent concentration and the amount of water to be treated. The concentrated agent and dilution water are diverted, sheared, and repeatedly merged within a flow channel formed by multiple stationary spiral blades 220, achieving thorough and uniform mixing of the concentrated agent and dilution water, thus meeting the process requirements for online dilution and homogenization mixing of wastewater treatment agents.

[0043] When it is necessary to clean the concentrated chemicals remaining on the inner wall of the mixing pipe 210 and the surface of the spiral blades 220, the mixing unit switches to the second operating mode. At this time, the concentrated chemicals supply is shut off, and only dilution water is introduced into the mixing pipe 210. The dilution water is input in a pulsed manner, and the supply power of the dilution water is increased, increasing the flow velocity of the dilution water inside the mixing pipe 210. The high-speed flowing dilution water can clean the concentrated chemicals remaining on the surface of the spiral blades 220. Simultaneously, the high-speed flowing dilution water applies a continuous axial thrust to the multiple spiral blades 220. This axial thrust overcomes the axial elasticity of the first compression spring 240, driving the multiple spiral blades 220 as a whole to move along the central axis 230 towards the outlet end of the mixing pipe 210. This causes the limiting protrusion 232 on the central axis 230 to disengage from the limiting groove 221 on the inner wall of the spiral blades 220 and enter the rotating groove 222 connected to the limiting groove 221. The engagement of the limiting protrusion 232 and the rotating groove 222 releases the restriction on the circumferential rotation of the spiral blade 220 relative to the central axis 230. The high-speed flowing dilution water continuously applies a circumferential driving force to the spiral blade 220, causing the spiral blade 220 to rotate circumferentially around the central axis 230. The outer wall of the spiral blade 220 forms a dynamic scraping engagement with the inner wall of the mixing pipe 210, and the outer wall of the spiral blade 220 continuously and comprehensively scrapes and cleans the inner wall of the mixing pipe 210.

[0044] Meanwhile, since the spiral directions of two adjacent spiral blades 220 are opposite, driven by the high-speed flow of dilution water, the rotation directions of the two adjacent spiral blades 220 are opposite, and the mutual contact edges of the two adjacent spiral blades 220 form relative frictional motion, thereby achieving the cleaning of residual agents and impurities on the edge surfaces of multiple spiral blades 220.

[0045] After the cleaning operation is completed, the flow velocity of the dilution water inside the mixing pipe 210 is slowly reduced, decreasing the axial thrust and circumferential driving force of the dilution water on the spiral blades 220. This allows the spiral blades 220 to slowly return to their original position along the central axis 230 during rotation. The axial elastic force of the first compression spring 240 is gradually and completely released, driving the multiple spiral blades 220 to move towards the water inlet end of the mixing pipe 210. This allows the limiting protrusion 232 on the central axis 230 to smoothly re-engage into the limiting groove 221 on the inner wall of the spiral blades 220, thus completely restricting the circumferential rotation of the spiral blades 220 relative to the central axis 230. The mixing unit stably returns from the second working mode to the first working mode, and the equipment re-enters the normal reagent mixing working state.

[0046] Furthermore, in wastewater treatment using concentrated agents such as alkali solutions, carbon sources, or phosphorus removal agents, these concentrated agents readily react chemically with dilution water, generating insoluble inorganic deposits. These deposits continuously adhere to, compact, and harden on the surface of the stationary spiral blades 220, gradually forming a high-strength, hard scale layer. The simple scouring force of conventional dilution water is weak and cannot effectively peel off and remove this hard scale layer. Long-term accumulation of the hard scale layer will continuously reduce the effective flow cross-sectional area inside the mixing pipe 210, decreasing the efficiency of agent dilution and mixing. Therefore, the mixing unit also includes a flexible layer 223 and an expansion structure covering the surfaces of multiple spiral blades 220.

[0047] Specifically, each helical blade 220 has a flexible layer 223 covering its surface, which possesses controllable elastic deformation and restoring capabilities. The flexible layer 223 is stably pressed onto the surface of the helical blade 220 by multiple sealing strips 224. The shape of the sealing strips 224 perfectly matches the helical extension trajectory of the helical blade 220, and the multiple sealing strips 224 are respectively snapped and fixed at each edge of the helical blade 220, achieving a tight fit and sealing fixation between the flexible layer 223 and the surface of the helical blade 220. The surface of the flexible layer 223 is coated with a polytetrafluoroethylene (PTFE) coating. The PTFE coating has extremely low surface energy and excellent anti-adhesion properties, which can significantly reduce the adhesion of concentrated agents and deposits to the surface of the helical blade 220, reducing the initial amount of highly viscous concentrated agents and scale precursors adhering to the surface of the helical blade 220.

[0048] The central shaft 230 is also provided with a central flow channel 233 and multiple connecting holes 234. The central flow channel 233 extends axially along the central shaft 230, and the inlet end of the central flow channel 233 extends and penetrates the end face of the central shaft 230 near the water inlet end of the mixing pipe 210, so that high-speed flowing dilution water can stably enter the interior of the central flow channel 233. Each connecting hole 234 is provided corresponding to a spiral blade 220, and the connecting hole 234 penetrates the wall of the central shaft 230 radially.

[0049] The expansion structure includes a first flow channel 225 and a water passage 226. Each spiral blade 220 has multiple first flow channels 225 radially formed inside; each spiral blade 220 has multiple water passages 226 connected to the first flow channels 225 on its surface.

[0050] When the mixing unit is in the first working mode, the limiting protrusion 232 is located inside the limiting groove 221, and the inner wall of the spiral blade 220 is tightly attached to the outer wall of the central shaft 230, completely sealing the connecting hole 234; at the same time, the flexible layer 223 is tightly attached to the surface of the spiral blade 220, completely sealing the water passage hole 226. At this time, the central flow channel 233 and the first flow channel 225 are isolated from each other, and the concentrated agent and dilution water cannot enter the interior of the first flow channel 225. The flexible layer 223 remains flat and attached, maintaining the complete flow channel shape on the surface of the spiral blade 220, ensuring the stable diversion, shearing and multi-stage confluence effect of the spiral blade 220 on the concentrated agent and dilution water, and meeting the usage requirements for agent preparation and uniform mixing under normal sewage treatment conditions.

[0051] When the mixing unit switches to the second working mode, the spiral blade 220 moves axially along the central axis 230, the limiting protrusion 232 enters the rotating groove 222, and a stable annular gap is formed between the inner wall of the spiral blade 220 and the outer wall of the central axis 230. The central flow channel 233 is connected to the first flow channel 225 inside the spiral blade 220 through the connecting hole 234. Under the action of its own pressure and flow inertia, the high-speed flowing dilution water enters the first flow channel 225 through the central flow channel 233 and the connecting hole 234 in sequence, and is continuously sprayed outward from the water passage 226 on the surface of the spiral blade 220, forming a uniform pressure field on the inner side of the flexible layer 223, driving the flexible layer 223 to bulge outward along the radial direction of the spiral blade 220 and produce controllable elastic deformation.

[0052] The bulging of the flexible layer 223 can directly destroy the bonding interface between the hard scale layer and the surface of the flexible layer 223, change the stress state of the scale layer, and cause the hard scale layer to quickly crack, delaminate, warp and peel off as a whole. The peeled scale layer breaks down and is discharged with the dilution water, further achieving the cleaning of the surface of the spiral blade 220.

[0053] Understandably, to facilitate industrial mass production, the helical blade 220 can be formed using sand casting. Sand casting offers advantages such as low forming difficulty, adaptability to complex helical structures, controllable production costs, and short production cycles, enabling precise forming of the overall helical profile and basic structure of the helical blade 220. After sand casting, multiple radially distributed first flow channels 225 are then machined inside the helical blade 220 to ensure that the aperture size, spacing, and connectivity of the first flow channels 225 meet design requirements, balancing production convenience and equipment operational reliability.

[0054] In one embodiment, to reduce the cost of reagent dilution, the dilution process of some concentrated reagents can directly use the wastewater to be treated as dilution water. The wastewater to be treated usually contains a large number of ribbon-like impurities such as hair and fibers. These ribbon-like impurities are easily intercepted and caught by the leading edge of the stationary spiral blade 220, and continue to accumulate and entangle into clumps at the leading edge of the spiral blade 220, thereby intercepting solid suspended particles in the wastewater, ultimately causing local blockage in the mixing pipe 210, reducing the reagent mixing effect and the stability of system operation.

[0055] Based on this, the end face of the helical blade 220 facing the fluid flow direction is configured as two symmetrically arranged guide slopes 227. The guide slopes 227 are arranged at an angle along the fluid flow direction, forming a guide structure that is narrow at the front and wide at the back. The guide slopes 227 can guide and disperse ribbon-like impurities in the sewage, allowing the ribbon-like impurities to pass smoothly through the leading edge area of ​​the helical blade 220 along the slope, reducing the hanging, entanglement, and accumulation of ribbon-like impurities on the end face of the helical blade 220.

[0056] Meanwhile, when the mixing unit switches to the second working mode, the adjacent spiral blades 220 rotate in opposite directions under the drive of the dilution water. The end faces and edges of the adjacent spiral blades 220 form a relative shearing and scraping motion, which shears, peels and removes the residual ribbon-like impurities hanging on the surface of the spiral blades 220 and the guide slope 227, further realizing the automatic dredging and cleaning of the surface of the spiral blades 220 and the internal flow channel of the mixing pipe 210, ensuring the long-term stable operation of the system.

[0057] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0058] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A dosing device for wastewater treatment, characterized in that, include: A mixing unit includes a mixing pipe and multiple helical blades; the multiple helical blades are rotatably mounted inside the mixing pipe along the axial direction of the mixing pipe, and the helical directions of adjacent two helical blades are opposite; the outer walls of the multiple helical blades are in contact with the inner wall of the mixing pipe. A drive unit is used to drive multiple fluids to flow through the mixing pipe; The mixing unit has a first operating mode and a second operating mode, and can switch between the first operating mode and the second operating mode according to the flow rate of the fluid flowing through the mixing pipe. When the mixing unit is in the first operating mode, the plurality of spiral blades are stationary relative to the mixing pipe to mix the various fluids flowing through it. When the mixing unit is in the second operating mode, two adjacent spiral blades rotate relative to each other in opposite directions under the drive of the fluid. The mixing unit also includes a central shaft and a limiting structure. The central shaft is coaxially fixedly installed inside the mixing pipe, and multiple spiral blades are rotatably sleeved on the central shaft. The limiting structure includes a limiting protrusion, a limiting groove, and a rotating groove; multiple limiting protrusions are provided, and the multiple limiting protrusions are fixedly provided on the outer wall of the central shaft, with each limiting protrusion corresponding to one of the spiral blades; the inner wall of each spiral blade is provided with a limiting groove and a rotating groove, and the limiting groove and the rotating groove are connected along the axial direction of the central shaft; When the mixing unit is in the first working mode, the limiting protrusion is fully embedded in the limiting groove; when the mixing unit is in the second working mode, the limiting protrusion is fully embedded in the rotating groove. The mixing unit further includes a first elastic element, which is disposed between one of the spiral blades and the mixing pipe. The elastic force of the first elastic element always keeps the limiting protrusion located in the limiting groove. The hybrid unit also includes a flexible layer and an expansion structure; the surface of each of the helical blades is covered with the flexible layer, which is capable of deformation. The expansion structure includes a first flow channel, which is disposed inside the spiral blade, and the surface of the spiral blade is provided with a water passage hole communicating with the first flow channel. When the mixing unit is in the first operating mode, the flexible layer blocks the water passage; when the mixing unit is in the second operating mode, fluid enters the first flow channel and flows out from the water passage to drive the flexible layer to bulge and deform.

2. The dosing equipment for wastewater treatment according to claim 1, characterized in that, The central shaft is further provided with a central flow channel, which is connected to the first flow channel inside the spiral blade, and is used to deliver fluid to the first flow channel in the second working mode.

3. The dosing equipment for wastewater treatment according to claim 1, characterized in that, The surface of the flexible layer is coated with polytetrafluoroethylene.

4. The dosing equipment for wastewater treatment according to claim 1, characterized in that, The mixing unit also includes a retaining ring, which is detachably and fixedly connected to the mixing pipe by a thread; the central shaft extends radially with a limiting rod, and the retaining ring is provided with a groove that cooperates with the limiting rod. The limiting rod is embedded in the groove to restrict the axial movement of the central shaft relative to the mixing pipe.

5. The dosing equipment for wastewater treatment according to claim 1, characterized in that, The spiral blades are provided with flow guiding slopes on both axial end faces, and the flow guiding slopes are inclined along the flow direction of the fluid.

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