A precise proportioning device for sewage treatment

Abstract

The present application relates to the field of sewage treatment, and particularly relates to a precise proportioning device for sewage treatment. The device comprises a rack and a mixer. The rack is provided with a quantitative pumping assembly. The mixer comprises a mixing pipe and a plurality of mixing elements arranged in the mixing pipe. The liquid inlet end of the mixing pipe is connected to the output end of the quantitative pumping assembly, and the liquid outlet end of the mixing pipe is connected to a sewage treatment tank. The mixing elements are configured to mix the medium in the mixing pipe. The mixing elements are slidably connected to the mixing pipe and can slide along the axis of the mixing pipe. The present application can switch the mixer among various states, such as equal distance, sparse in front and dense in back, dense in front and sparse in back, and so on, by adjusting the distance between the mixing elements. The present application can adapt to conventional liquid-liquid mixing conditions, gas-liquid efficient mass transfer conditions, and high-concentration emulsion dispersion conditions, and solve the technical problem that the traditional pipeline mixing device cannot meet the requirements of high-viscosity emulsion dispersion and gas-liquid mixing flow field. The present application greatly reduces the equipment selection difficulty and the modification cost.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment, and more specifically to a precise proportional dosing device for wastewater treatment. Background Technology

[0002] Wastewater treatment is a technological system that purifies water bodies using physical, chemical, and biological methods to meet discharge or reuse standards, and it is an important component of environmental protection. In related technologies, wastewater treatment often requires the addition of chemicals in specific proportions to induce coagulation, neutralization, and oxidation reactions, thereby decomposing or removing harmful substances from the wastewater. When adding chemicals to wastewater, a chemical dilution and mixing device is needed to dilute and mix the concentrated chemical solution to meet the application requirements.

[0003] In-line static mixers are commonly used dilution and mixing devices in wastewater treatment. They can thoroughly mix water and concentrated chemical solutions. As a pipeline mixing device without moving parts, it uses internal mixing unit structures such as spiral blades or corrugated sheets to cause fluid segmentation, shearing, rotation, and remixing, utilizing the kinetic energy of the medium itself to achieve rapid mixing. However, existing in-line static mixers have a single operating mode and cannot well adapt to concentrated chemical solutions with different properties and dilution methods, such as liquid-liquid dilution mixing or gas-liquid dilution mixing, resulting in poor applicability.

[0004] The information disclosed in the background section of this invention is intended only to enhance the understanding of the general background of this invention, and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes a precise proportional dosing device for wastewater treatment, which solves the problems of limited working modes and poor adaptability of existing dosing devices.

[0006] The present invention provides a precise proportional dosing device for wastewater treatment, which adopts the following technical solution: including:

[0007] The frame is equipped with a metering pump assembly.

[0008] A mixer includes a mixing tube and several mixing elements disposed inside the mixing tube. The mixing tube has an inlet end and an outlet end. The inlet end of the mixing tube is connected to the output end of a metering pump assembly, and the outlet end of the mixing tube is connected to a wastewater treatment tank to receive various media pumped by the metering pump assembly and transport the media to the wastewater treatment tank. The mixing elements are configured to mix the media inside the mixing tube. Several mixing elements are slidably inserted along the axial direction of the mixing tube, and several mixing elements can slide along the axial direction of the mixing tube so that the distance between the mixing elements can be adjusted.

[0009] When the medium in the mixing tube is water and a reagent with a viscosity lower than the preset value, the spacing between adjacent mixing elements is equal.

[0010] When the medium in the mixing tube is gas and liquid, the distance between adjacent mixing elements gradually decreases from the liquid inlet end to the liquid outlet end.

[0011] When the medium in the mixing tube is water and a reagent with a viscosity higher than the preset value, the distance between adjacent mixing elements gradually increases from the inlet end to the outlet end.

[0012] Optionally, the mixing pipe includes a main pipe and end pipes disposed at both ends of the main pipe. The end pipes are fixed to the frame, and the end pipe at the liquid inlet end is connected to the output end of the metering pump assembly, while the end pipe at the liquid outlet end is connected to the wastewater treatment tank. The main pipe and the end pipes are rotatably connected.

[0013] Several limiting rods are connected between the two end tubes. The limiting rods are located inside the main tube and the end tubes and are evenly distributed along the circumference of the main tube. Several spiral grooves are provided on the inner circumferential wall of the main tube.

[0014] Each mixing element is provided with a snap-fit ​​groove and a mating protrusion. The snap-fit ​​groove is slidably snapped into the corresponding limiting rod, and the mating protrusion is slidably set in the corresponding spiral groove. The pitch of the spiral groove corresponding to the mixing element at the end gradually increases from the spiral groove corresponding to the mixing element in the middle.

[0015] Optionally, the main pipe and end pipes are provided with scale markings and direction markings.

[0016] Optionally, the main tube is provided with snap-fit ​​shaft sections at both ends, and snap-fit ​​ring grooves are provided inside the two end tubes. The snap-fit ​​shaft sections are inserted into the snap-fit ​​ring grooves. Fastening bolts are provided on both end tubes. The fastening bolts are screwed to the end tubes and their inner ends pass through the end tubes and can abut against the snap-fit ​​shaft sections.

[0017] Optionally, a rotating seal ring is provided between the main pipe and the end pipe.

[0018] Optionally, the mixing element includes a first mixing blade and a second mixing blade. Both the first mixing blade and the second mixing blade include two end blades and two intermediate blades. The two intermediate blades are semi-elliptical and are vertically connected on the side away from the elliptical arc to form a cross shape. The two end blades are vertically connected to the two ends of the two intermediate blades, and the end blades near the intermediate blades are adapted to the socket shape formed by the two intermediate blades, that is, the end of the two end blades near the intermediate blades is triangular. The intermediate blades located on the same side of the end blades in the first mixing blade and the second mixing blade are connected to different opposite angles of the two end blades.

[0019] The first and second mixing blades are alternately arranged inside the mixing tube. The end blades of adjacent first and second mixing blades facing each other are perpendicular to each other and slidably inserted. The first and second mixing blades are aligned with the mixing tube and their corresponding outer edges slide in contact with the inner peripheral wall of the mixing tube.

[0020] Optionally, each end blade has an insertion groove at the end opposite to the middle blade. The insertion groove extends along the axis of the mixing tube, and the end blades of the first mixing blade and the second mixing blade facing each other are slidably inserted into each other through the insertion groove.

[0021] Optionally, two limiting plates are provided on the end blades of the first and second mixing blades located on the same side. The limiting plates are located at the slot opening of the corresponding insertion slide and are arranged on both sides of the insertion slide. The face-to-face surfaces of the two limiting plates are coplanar with the corresponding surfaces of the insertion slide. The limiting plates are perpendicular to the end blades.

[0022] Optionally, the metering pump assembly includes a first metering pump, a second metering pump, and a third metering pump, with the input ends of the first metering pump, the second metering pump, and the third metering pump connected to the medium source and the output ends connected to the liquid inlet of the mixing tube.

[0023] Optionally, the precise proportional dosing device for wastewater treatment further includes a pipe joint with four connecting ports. The output end of the first metering pump, the output end of the second metering pump, the output end of the third metering pump, and the end pipe of the mixing pipe inlet are respectively connected to the four connecting ports of the pipe joint.

[0024] The end pipe located at the liquid outlet end of the mixing pipe is connected to an outlet pipe, which leads into the sewage treatment tank.

[0025] The beneficial effects of this invention are as follows: The precision proportional dosing device for wastewater treatment of this invention achieves switching between multiple states of a single mixer, such as "equidistant, sparse in front and dense in back, and dense in front and sparse in back", by adjusting the spacing of the mixing elements. It can adapt to conventional liquid-liquid mixing conditions, gas-liquid high-efficiency mass transfer conditions, and high-concentration polymer emulsion dispersion and swelling conditions. It effectively solves the technical problem that traditional fixed pipeline mixing devices cannot simultaneously meet the requirements of high-viscosity emulsion dispersion and gas-liquid mixing flow field, and greatly reduces the difficulty of equipment selection and modification costs.

[0026] Furthermore, by setting the mixing tube as a split structure including the main tube and the end tubes, and allowing the main tube to rotate, the spiral grooves with different pitches on the main tube and the matching protrusions on the mixing element can create a complex flow field in the same mixing tube where the shear rate increases or decreases axially. This structure can not only accurately match the mixing energy according to the fluid rheological characteristics, but also achieve complex process control through simple mechanical rotation operation, making it easy to operate and compact in structure. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the overall structure of a precision proportional dosing device for wastewater treatment according to the present invention;

[0029] Figure 2 This is a top view of a precise proportional dosing device for wastewater treatment according to the present invention;

[0030] Figure 3 This is a schematic diagram of the mixer in this invention;

[0031] Figure 4 for Figure 3 Side view;

[0032] Figure 5 for Figure 4 Sectional view along the middle AA direction Figure 1 (The mixer is in the first state);

[0033] Figure 6 for Figure 4 Sectional view along the middle AA direction Figure 2 (The mixer is in the second state);

[0034] Figure 7 for Figure 4 Sectional view along the middle AA direction Figure 3 (The mixer is in the third state);

[0035] Figure 8 This is an exploded view of the mixer in this invention;

[0036] Figure 9 This is a schematic diagram of the mixing tube of the mixer in this invention;

[0037] Figure 10 for Figure 9 Side view;

[0038] Figure 11 for Figure 10 BB section view;

[0039] Figure 12 This is a schematic diagram of the mixing element structure of the mixer in this invention.

[0040] In the picture:

[0041] 100. Frame; 110. First metering pump; 120. Second metering pump; 130. Pipe fitting; 140. Discharge pipe;

[0042] 200. Mixer;

[0043] 210. Mixing pipe; 211. Main pipe; 2111. Spiral groove; 212. End pipe; 2121. Limiting rod; 2122. Fastening bolt; 2123. Connecting ring;

[0044] 220. Mixing element; 221. First mixing blade; 2211. Intermediate blade; 22111. Snap-fit ​​groove; 22112. Mating protrusion; 2212. End blade; 22121. Insertion groove; 22122. Limiting plate; 222. Second mixing blade. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] like Figures 1 to 12 As shown in the figure, an embodiment of the present invention provides a precision proportional dosing device for wastewater treatment, including a frame 100 and a mixer 200; a metering pump assembly is provided on the frame 100; the mixer 200 includes a mixing pipe 210 and a plurality of mixing elements 220 disposed inside the mixing pipe 210; the mixing pipe 210 has an inlet end and an outlet end, the inlet end of the mixing pipe 210 is connected to the output end of the metering pump assembly, and the outlet end of the mixing pipe 210 is connected to the wastewater treatment tank, so as to receive various media (agents, water or gas, etc.) pumped by the metering pump assembly and transport the media to the wastewater treatment tank; the mixing elements 220 are configured to mix the media in the mixing pipe 210, and the plurality of mixing elements 220 are slidably inserted along the axial direction of the mixing pipe 210 and the plurality of mixing elements 220 can slide along the axial direction of the mixing pipe 210 so that the distance between the mixing elements 220 can be adjusted;

[0047] When the medium in the mixing tube 210 is water and a reagent with a viscosity lower than a preset value, the spacing between adjacent mixing elements 220 is equal.

[0048] When the medium in the mixing tube 210 is gas and liquid, the distance between adjacent mixing elements 220 gradually decreases from the liquid inlet end to the liquid outlet end.

[0049] When the medium in the mixing tube 210 is water and a reagent with a viscosity higher than the preset value, the distance between adjacent mixing elements 220 gradually increases from the inlet end to the outlet end.

[0050] During operation, the metering pumping unit accurately pumps the various media to be mixed into the mixer 200 according to the required proportions, and mixes them in the mixer 200. The mixed media are then fed into the sewage treatment tank to treat the sewage.

[0051] When the medium to be mixed is water and a reagent with a viscosity lower than a preset value, that is, when it is necessary to dilute and mix conventional low-viscosity, easily soluble liquid chemical reagents (such as polyaluminum chloride PAC, acid-base regulators, sodium hypochlorite solution, etc.) with water, the mixer 200 is in the first state. At this time, the spacing between adjacent mixing elements 220 is equal (equidistant arrangement). The shear rate and pressure drop generated by the medium when passing through each mixing element 220 remain stable. In the mixing tube 210, it is subjected to constant frequency flow direction change and radial deflection, thereby forming a continuous and uniform concentration gradient on the cross section of the mixing tube 210, and the mixing intensity is stable and controllable.

[0052] When the medium to be mixed is gas and liquid, that is, when gas and liquid need to be mixed and diluted (for example, oxygen is introduced into ferrous sulfate solution to obtain ferric salt; ozone or air is added to hydrogen peroxide to treat organic matter that is difficult to degrade), the mixer 200 is in the second state, at which time the distance between adjacent mixing elements 220 gradually decreases from the liquid inlet end to the liquid outlet end.

[0053] It is understandable that when gas is injected into the mixing tube 210 through the metering pump assembly, it is prone to agglomerate into a large gas mass due to surface tension. If it directly enters the high resistance dense area, it is easy to generate "gas locking" at the leading edge of the mixing element 220, which will hinder the water flow and cause pressure fluctuations in the pipeline network. This invention adjusts the spacing of the mixing elements 220 so that they are arranged in a more sparse and denser manner in the direction of medium flow. The sparser arrangement of the front mixing elements 220 provides a low-resistance buffer zone for the medium, and uses a gentle deflection effect to initially divide the large air pockets, forming a more uniform gas-liquid two-phase flow. This overcomes the gas resistance phenomenon and effectively avoids system pump stalling and flow fluctuations caused by the injection of large amounts of gas, ensuring the stable operation of the hydraulic system. After the pre-distributed gas-liquid mixture enters the high-density arrangement of the rear mixing elements 220, the high-frequency fluid cutting significantly increases the local fluid shear rate, overcomes the surface tension of the bubbles, further breaks the dispersed bubbles into microbubbles, reduces the average particle size (Sauter average diameter), and significantly increases the specific surface area of ​​gas-liquid contact, thereby improving the solubility and mass transfer rate of gases such as ozone and improving the mixing effect.

[0054] When the medium to be mixed is water and a drug with a viscosity higher than a preset value, such as when a high-concentration polymer emulsion (polymer flocculant solution) needs to be mixed and diluted with water, the mixer 200 is in the third state. At this time, the distance between adjacent mixing elements 220 gradually increases from the liquid inlet end to the liquid outlet end.

[0055] It is understandable that high-concentration polymer emulsions have high viscosity. Upon initial contact with dilution water, there is a significant difference in kinematic viscosity between the two phases. The outer edge of the high-viscosity emulsion is preferentially hydrated in water, forming high-viscosity gel agglomerates with an outer layer and an undispersed interior. This invention adjusts the spacing of the mixing elements 220 to create a denser front and sparser back arrangement in the medium flow direction. The denser mixing elements 220 at the front provide higher mechanical shear force in the initial fluid convergence stage, causing the emulsion droplets to break up rapidly and disperse uniformly in the aqueous phase, thereby inhibiting gel aggregation. The sparser mixing elements 220 at the rear significantly reduce the local shear rate, providing a low-shear hydrodynamic relaxation environment for the expansion of polymer molecular chains. This avoids the mechanical degradation of the polymer in the hydrolyzed solution caused by high-intensity mechanical shear, and simultaneously preserves the effective molecular weight of the polymer and the flocculation properties of the solution.

[0056] The solution in this embodiment, by adjusting the spacing of the mixing elements 220, enables the mixer 200 to switch between multiple states such as "equidistant, sparse in front and dense in back, and dense in front and sparse in back". It can adapt to conventional liquid-liquid mixing conditions, gas-liquid high-efficiency mass transfer conditions, and high-concentration polymer emulsion dispersion and swelling conditions. It effectively solves the technical problem that traditional fixed pipeline mixing devices cannot simultaneously meet the requirements of high-viscosity emulsion dispersion and gas-liquid mixing flow field, and greatly reduces the difficulty of equipment selection and modification costs.

[0057] In a further embodiment, to facilitate the adjustment of the spacing between the mixing elements 220, the mixing tube 210 preferably includes a main tube 211 and end tubes 212 disposed at both ends of the main tube 211. The end tubes 212 are fixed to the frame 100, and the end tube 212 at the liquid inlet end is connected to the output end of the metering pump assembly, while the end tube 212 at the liquid outlet end is connected to the sewage treatment tank. The main tube 211 and the end tubes 212 are rotatably connected.

[0058] A number of limiting rods 2121 are connected between the two end tubes 212. The limiting rods 2121 are located inside the main tube 211 and the end tubes 212 and are evenly distributed along the circumference of the main tube 211. A number of spiral grooves 2111 are provided on the inner circumferential wall of the main tube 211.

[0059] Each mixing element 220 is provided with a snap-fit ​​groove 22111 and a mating protrusion 22112. The snap-fit ​​groove 22111 is slidably snapped into the corresponding limiting rod 2121, and the mating protrusion 22112 is slidably disposed in the corresponding spiral groove 2111. The pitch of the spiral groove 2111 corresponding to the mixing element 220 at the end gradually increases from the spiral groove 2111 corresponding to the mixing element 220 in the middle.

[0060] When mixer 200 is in the first state, refer to Figure 5 At this point, the spacing between each mixing element 220 is equal, i.e., A1=B1=C1=D1=E1=F1=G1. When it is necessary to adjust the mixer 200 to the second state, rotate the main pipe 211 around the set direction, causing each mixing element 220 to move towards the liquid outlet end of the mixing pipe 210. Because the pitch of the spiral groove 2111 where the mixing elements 220 at both ends are located is small, and the pitch of the spiral groove 2111 where the mixing elements 220 in the middle are located is large, the mixing elements 220 at both ends move a small distance, and the mixing elements 220 in the middle move a large distance. This causes the distance between adjacent mixing elements 220 to gradually decrease from the liquid inlet end to the liquid outlet end. Figure 6 , Figure 6 In the order A2>B2>C2>D2>E2>F2>G2; when the mixer 200 needs to be adjusted to the third state, the main pipe 211 is rotated in the opposite direction of the set direction, causing each mixing element 220 to move towards the liquid inlet end of the mixing pipe 210. Because the pitch of the spiral groove 2111 where the mixing elements 220 at both ends are located is small, and the pitch of the spiral groove 2111 where the mixing elements 220 in the middle are located is large, the mixing elements 220 at both ends move a small distance, and the mixing elements 220 in the middle move a large distance. This causes the distance between adjacent mixing elements 220 to gradually increase from the liquid inlet end to the liquid outlet end, as shown in the reference. Figure 7 , Figure 7 In Chinese, A3 <B3<C3<D3<E3<F3<G3。

[0061] In this embodiment, the combination of spiral grooves 2111 with different pitches and matching protrusions 22112 allows a complex flow field with shear rate increasing or decreasing along the axial direction to be constructed within the same mixing tube 210. This structure can not only accurately match the mixing energy according to the fluid rheological characteristics, but also achieve complex process control through simple mechanical rotation operation, making it easy to operate and compact in structure.

[0062] It is understandable that the rotation direction of the main pipe 211 is adapted to the rotation direction of the spiral groove 2111. That is, when the spiral groove 2111 rotates to the right, the aforementioned set direction is clockwise, and when the spiral groove 2111 rotates to the left, the aforementioned set direction is counterclockwise.

[0063] In a further embodiment, to improve ease of operation, scale markings and direction markings are provided on the main pipe 211 and the end pipe 212. The scale markings have a zero mark position. When the zero marks of the main pipe 211 and the end pipe 212 are aligned, the distance between each mixing element 220 is equal. Rotating the main pipe 211 according to the direction markings can adjust the mixer 200 to the second or third state. The rotation angle of the main pipe 211 can be controlled by referring to the scale markings to adjust the density of the arrangement of each mixing element 220, thereby making the control more convenient and precise.

[0064] In a further embodiment, the main tube 211 is provided with snap-fit ​​shaft sections at both ends, and the two end tubes 212 are provided with snap-fit ​​ring grooves inside. The snap-fit ​​shaft sections are inserted into the snap-fit ​​ring grooves. Both end tubes 212 are provided with fastening bolts 2122. The fastening bolts 2122 are screwed to the end tubes 212 and their inner ends pass through the end tubes 212 and can abut against the snap-fit ​​shaft sections.

[0065] When the device is working normally, the fastening bolt 2122 abuts against the snap-fit ​​shaft section to lock the relative position of the main pipe 211 and the end pipe 212. When it is necessary to change the state of the mixer 200, tighten the fastening bolt 2122 and move it outward. At this time, the main pipe 211 can be rotated. After the angle of the main pipe 211 is adjusted, tighten the fastening bolt 2122 again. The operation is simple and convenient.

[0066] In a further embodiment, a rotating sealing ring (not shown in the figure) is provided between the main pipe 211 and the end pipe 212 to achieve a rotating seal between the main pipe 211 and the end pipe 212.

[0067] In a further embodiment, to facilitate the installation and disassembly of the end tube 212 and the main tube 211, each end tube 212 is provided with a connecting ring 2123, which is screwed to the end tube 212, and the limiting rod 2121 connects the two connecting rings 2123.

[0068] In a further embodiment, the mixing element 220 includes a first mixing blade 221 and a second mixing blade 222. Both the first mixing blade 221 and the second mixing blade 222 include two end blades 2212 and two intermediate blades 2211. The two intermediate blades 2211 are semi-elliptical and are vertically connected on the side away from the elliptical arc to form a cross shape. The two end blades 2212 are respectively vertically connected to the two ends of the two intermediate blades 2211, and the side of the end blades 2212 near the intermediate blades 2211 is adapted to the socket shape formed by the two intermediate blades 2211, that is, the end of the two end blades 2212 near the intermediate blades 2211 is triangular. The intermediate blades 2211 located on the same side of the end blades 2212 in the first mixing blade 221 and the second mixing blade 222 are connected to different opposite corners of the two end blades 2212.

[0069] The first mixing blade 221 and the second mixing blade 222 are alternately arranged inside the mixing tube 210. The end blades 2212 of adjacent first mixing blades 221 and second mixing blades 222 face each other and are slidably inserted. The first mixing blades 221 and second mixing blades 222 are aligned with the mixing tube 210 and their corresponding outer edges are in sliding contact with the inner peripheral wall of the mixing tube 210. That is, the outer edge of the elliptical arc of the middle blade 2211 and the outer edges of both sides of the width direction of the end blades 2212 are in sliding contact with the inner peripheral wall of the mixing tube 210.

[0070] The solution in this embodiment, through the special arrangement of the end blade 2212 and the middle blade 2211, not only enables the medium to achieve efficient mixing during the flow process through diversion, radial mixing and reverse swirling, without the need for additional power components, resulting in low energy consumption and high mixing efficiency, but also facilitates the sliding connection of the first mixing blade 221 and the second mixing blade 222, which is beneficial for the mixer 200 to achieve state adjustment.

[0071] Furthermore, the snap-fit ​​groove 22111 and the mating protrusion 22112 are both provided on the outer peripheral wall of the intermediate blade 2211. To improve the connection reliability and ensure force balance, each intermediate blade 2211 is provided with one mating protrusion 22112 and two snap-fit ​​grooves 22111. The mating protrusion 22112 is located in the middle of the intermediate blade 2211, and the two snap-fit ​​grooves 22111 are located on both sides of the mating protrusion 22112. Correspondingly, four limiting rods 2121 are provided. Each first mixing blade 221 and each second mixing blade 222 has two corresponding spiral grooves 2111 to match the mating protrusion 22112.

[0072] In a further embodiment, refer to Figure 8Each end blade 2212 has an insertion groove 22121 at the end opposite to the middle blade 2211. The insertion groove 22121 extends along the axis of the mixing tube 210. The end blades 2212 facing each other, the first mixing blade 221 and the second mixing blade 222, are slidably inserted into each other through the insertion groove 22121. Furthermore, two limiting plates 22122 are provided on the end blades 2212 on the same side of the first mixing blade 221 and the second mixing blade 222. The limiting plates 22122 are located at the opening of the corresponding insertion groove 22121 and are arranged on both sides of the insertion groove 22121. The surfaces of the two limiting plates 22122 facing each other are coplanar with the corresponding surfaces of the insertion groove 22121. The limiting plates 22122 are perpendicular to the end blades 2212. By setting the limiting plate 22122, the sliding insertion of the first mixing blade 221 and the second mixing blade 222 becomes more convenient, and the mutual swaying of the first mixing blade 221 and the second mixing blade 222 after insertion is limited, making the insertion more reliable. In other embodiments, the insertion groove 22121 can also be set only on the end blade 2212 near the liquid inlet or liquid outlet end of the mixing tube 210 to realize the sliding insertion of the first mixing blade 221 and the second mixing blade 222. Compared with the embodiment in which the insertion groove 22121 is set on both end blades 2212, the sliding range of this embodiment is relatively small. Those skilled in the art can choose according to the actual use.

[0073] In a further embodiment, refer to Figure 1 and Figure 2 The metering pump assembly includes a first metering pump 110, a second metering pump 120, and a third metering pump (not shown in the figure). The input ends of the first metering pump 110, the second metering pump 120, and the third metering pump are connected to the medium source, and the output ends are connected to the liquid inlet of the mixing tube 210. The first metering pump 110, the second metering pump 120, and the third metering pump can meterly pump various media into the mixing tube 210 to realize the transfer of media.

[0074] In a further embodiment, to achieve communication between the mixing pipe 210 and the first metering pump 110, the second metering pump 120, and the third metering pump, the precision proportional dosing device for wastewater treatment of the present invention further includes a pipe joint 130. The pipe joint 130 has four connecting ports, and the output ends of the first metering pump 110, the second metering pump 120, the third metering pump, and the liquid inlet end of the mixing pipe 210 (specifically, the end pipe 212 of the liquid inlet end) are respectively connected to the four connecting ports of the pipe joint 130. The specific connection method is a flange connection, and a static sealing ring is provided between the mating flanges to ensure a seal.

[0075] Furthermore, in order to connect the mixing pipe 210 to the sewage treatment tank, the end pipe 212 located at the outlet end of the mixing pipe 210 is connected to the outlet pipe 140, which leads into the sewage treatment tank. The connection between the end pipe 212 and the outlet pipe 140 is also a flange connection, and a static sealing ring is set between the flanges to ensure sealing.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A precise proportional dosing device for wastewater treatment, characterized in that, include: The frame is equipped with a metering pump assembly. A mixer includes a mixing tube and several mixing elements disposed inside the mixing tube. The mixing tube has an inlet end and an outlet end. The inlet end of the mixing tube is connected to the output end of a metering pump assembly, and the outlet end of the mixing tube is connected to a wastewater treatment tank to receive various media pumped by the metering pump assembly and transport the media to the wastewater treatment tank. The mixing elements are configured to mix the media inside the mixing tube. Several mixing elements are slidably inserted along the axial direction of the mixing tube, and several mixing elements can slide along the axial direction of the mixing tube so that the distance between the mixing elements can be adjusted. When the medium in the mixing tube is water and a reagent with a viscosity lower than the preset value, the spacing between adjacent mixing elements is equal. When the medium in the mixing tube is gas and liquid, the distance between adjacent mixing elements gradually decreases from the liquid inlet end to the liquid outlet end. When the medium in the mixing tube is water and a reagent with a viscosity higher than the preset value, the distance between adjacent mixing elements gradually increases from the inlet end to the outlet end. The mixing pipe includes a main pipe and end pipes at both ends of the main pipe. The end pipes are fixed to the frame, and the end pipe at the liquid inlet is connected to the output end of the metering pump assembly, while the end pipe at the liquid outlet is connected to the wastewater treatment tank. The main pipe and the end pipes are rotatably connected. Several limiting rods are connected between the two end tubes. The limiting rods are located inside the main tube and the end tubes and are evenly distributed along the circumference of the main tube. Several spiral grooves are provided on the inner circumferential wall of the main tube. Each mixing element is provided with a snap-fit ​​groove and a mating protrusion. The snap-fit ​​groove is slidably snapped into the corresponding limiting rod, and the mating protrusion is slidably set in the corresponding spiral groove. The pitch of the spiral groove corresponding to the mixing element at the end gradually increases from the spiral groove corresponding to the mixing element in the middle. The mixing element includes a first mixing blade and a second mixing blade. Both the first mixing blade and the second mixing blade include two end blades and two middle blades. The two middle blades are semi-elliptical and are perpendicularly connected to each other on the side away from the elliptical arc to form a cross shape. The two end blades are perpendicularly connected to the two ends of the two middle blades, and the end blades near the middle blades are adapted to the socket shape formed by the two middle blades, that is, the end of the two end blades near the middle blades is triangular. The middle blades located on the same side of the end blades in the first mixing blade and the second mixing blade are connected to different opposite corners of the two end blades. The first and second mixing blades are alternately arranged inside the mixing tube. The end blades of adjacent first and second mixing blades facing each other are perpendicular to each other and slidably inserted. The first and second mixing blades are aligned with the mixing tube and their corresponding outer edges slide in contact with the inner peripheral wall of the mixing tube.

2. The precise proportional dosing device for wastewater treatment according to claim 1, characterized in that, The main pipe and end pipes are equipped with scale markings and direction markings.

3. The precise proportional dosing device for wastewater treatment according to claim 1, characterized in that, The main tube has snap-fit ​​shaft sections at both ends, and snap-fit ​​ring grooves are provided inside the two end tubes. The snap-fit ​​shaft sections are inserted into the snap-fit ​​ring grooves. Fastening bolts are provided on both end tubes. The fastening bolts are screwed to the end tubes and their inner ends pass through the end tubes and can abut against the snap-fit ​​shaft sections.

4. The precise proportional dosing device for wastewater treatment according to claim 1, characterized in that, A rotating sealing ring is provided between the main pipe and the end pipe.

5. The precise proportional dosing device for wastewater treatment according to claim 1, characterized in that, Each end blade has an insertion groove at the end opposite to the middle blade. The insertion groove extends along the axis of the mixing tube, and the end blades of the first mixing blade and the second mixing blade face to face are slidably inserted into each other through the insertion groove.

6. A precise proportional dosing device for wastewater treatment according to claim 5, characterized in that, Two limiting plates are provided on the end blades of the first and second mixing blades located on the same side. The limiting plates are located at the slot openings of the corresponding insertion slides and are arranged on both sides of the insertion slides. The surfaces of the two limiting plates facing each other are coplanar with the corresponding surfaces of the insertion slides. The limiting plates are perpendicular to the end blades.

7. The precise proportional dosing device for wastewater treatment according to claim 1, characterized in that, The metering pump assembly includes a first metering pump, a second metering pump, and a third metering pump. The input ends of the first metering pump, the second metering pump, and the third metering pump are connected to the medium source, and the output ends are connected to the liquid inlet of the mixing tube.

8. A precise proportional dosing device for wastewater treatment according to claim 1, characterized in that, The precise proportional dosing device for wastewater treatment also includes a pipe joint with four connection ports. The output end of the first metering pump, the output end of the second metering pump, the output end of the third metering pump, and the end pipe of the mixing pipe inlet are respectively connected to the four connection ports of the pipe joint. The end pipe located at the liquid outlet end of the mixing pipe is connected to an outlet pipe, which leads into the sewage treatment tank.

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