WO2024060535A1

WO2024060535A1 - Hydraulic screening device for low-density-difference composite powder biological carrier particles

Info

Publication number: WO2024060535A1
Application number: PCT/CN2023/081593
Authority: WO
Inventors: 钟言; 张健; 易境; 李小阳; 侯丹
Original assignee: 湖南三友环保科技有限公司
Priority date: 2022-09-19
Filing date: 2023-03-15
Publication date: 2024-03-28
Also published as: BE1030838A1; CN115475707A

Abstract

A hydraulic screening device for low-density-difference composite powder biological carrier particles, comprising: a feeding pipe system (610), a cylindrical section (620), a semi-ellipsoid section (630), a conical curved surface section (640), an overflow pipe system (650), and a driven impeller (660). The feeding pipe system (610) is connected to the tangent plane of the outer wall of the cylindrical section (620), a top cover (622) is arranged above the cylindrical section (620), the lower portion of the cylindrical section (620) is in butt joint with the semi-ellipsoid section (630), and the lower portion of the semi-ellipsoid section (630) is in butt joint with the conical curved surface section (640); the overflow pipe system (650) is fixedly mounted in the center of the top cover (622) of the cylindrical section (620), and is provided with a lower inserting pipe (652) and an upper connecting pipe (651), wherein the upper connecting pipe (651) is higher than the top cover (622) and configured to be connected to an external sludge discharging system, the lower inserting pipe (652) is located on the central axis of the cylindrical section (620) and the semi-ellipsoid section (630), and the driven impeller (660) is arranged on the outer side of the lower inserting pipe (652).

Description

A hydraulic screening device for low density difference composite powder biological carrier particles

Technical field

The invention relates to the technical field of sewage treatment, and in particular to a hydraulic screening device for low density difference composite powder biological carrier particles.

Background technique

Hydraulic cyclone is a widely used separation equipment for liquid heterogeneous mixtures. Its basic principle is to centrifuge two-phase or multi-phase mixtures such as liquid-liquid, liquid-solid, liquid-gas with a certain density difference. separation under action. The main body of the current equipment generally consists of five parts: a feed pipe, a cylindrical section, a conical section, an overflow section and an underflow pipe. Cyclone separation technology has the advantages of high separation efficiency, convenient operation, simple process, compact structure, small equipment size, small footprint, easy to realize continuous operation and automatic control, etc. Based on the above advantages, cyclone separation technology has developed from being only used for mineral processing to now being widely used in chemical industry, petroleum, powder engineering, metal processing, food, water treatment and other fields at home and abroad. In the field of water treatment, hydrocyclones have been used to some extent in activated sludge cyclone carbon release, separation of fine inorganic sand in sewage treatment plants, and aerobic granular sludge recovery.

In the process of urban sewage treatment, diatomite, zeolite, activated carbon, attapulgite, bentonite, perlite, iron-carbon powder, volcanic rock, biochar, Powder carriers such as vermiculite induce the formation of composite powder biological carrier particles with the powder carrier as the core and wrapped by microorganisms with strong adhesion. The separation target particle size is distributed between 25 and 100 μm, and the suspended growth microorganisms are in mucus and extracellular polymers. The biological flocs with weak binding force formed under the action constitute a "double mud" symbiotic sewage biochemical treatment microbial system. In order to realize the double mud age of the biochemical system and achieve the simultaneous nitrogen and phosphorus removal effect, the composite powder biological carrier particles must be separated from the biofloc. The separated composite powder biological carrier particles are recycled and the bioflocs are used as residual waste. Mud discharge. Currently, the most feasible separation solution is to use the hydrocyclone method. There are the following technical difficulties in achieving this goal:

(1) The equivalent particle size of the composite powder biological carrier particles is small, and improving the screening efficiency is one of the main difficulties in using the hydrocyclone method.

(2) The density difference between the composite powder biological carrier particles and the biological floc is small. The measured density difference between the composite powder biological carrier particles and the biological floc is only 0.07~0.15g/cm ³ , which is smaller than the 0.2g/cm ³ density difference between oil and water. It is The second main difficulty in using hydrocyclone to separate the two.

(3) Different from the current separation of tiny inorganic particles and single materials, there is a force combination between the composite powder biological carrier particles and the biological floc. It is not a simple mixing. During the separation process, the composite powder biological carrier particles and the biological flocs need to be combined. For floc separation, these forces must be overcome, which is the third main difficulty in using hydrocyclone to separate the two.

Contents of the invention

The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a hydraulic screening device for low density difference composite powder biological carrier particles, which can significantly improve the screening efficiency of low density difference composite powder biological carrier particles.

A low-density composite powder biological carrier particle hydraulic screening device according to an embodiment of the present invention comprises: a feed pipe system, a cylindrical section, a semi-ellipsoidal section, a conical surface section, an overflow pipe system and a passive impeller;

The feed pipe is connected to the outer wall section of the cylindrical section, a top cover is provided on the top of the cylindrical section, and the bottom is connected to the semi-ellipsoidal section, and the bottom of the semi-ellipsoidal section is connected to the conical surface section;

The overflow pipe system is fixedly installed in the center of the top cover on the upper part of the cylindrical section. The overflow pipe system is equipped with a lower insertion pipe and an upper nozzle. The upper nozzle is higher than the top cover and is used to communicate with the external mud discharge system. Connected, the lower insertion tube is located on the central axis of the cylindrical section and the semi-ellipsoid section, and the passive impeller is provided on the outside of the lower insertion tube.

According to some embodiments of the present invention, the feed pipe system includes a feed pipe, a square-to-round transition pipe and a shrink pipe;

Wherein, the feed nozzle is a nozzle with a circular standard flange for connecting to an external feed system. The circular interface of the water outlet end of the feed nozzle is consistent with the caliber of the round end of the square-to-round adapter pipe and is connected to each other. , the other end of the square-to-circle adapter pipe is a square port, its cross-sectional area is equal to or smaller than its round port end, and is consistent with the caliber of the square port of the shrink tube but connected, the shrink tube is a rectangular tapered tube, through The water cross section is a gradually shrinking arc-shaped flow channel structure.

According to some embodiments of the present invention, at least the following beneficial effects are achieved:

1. The feed pipe system of the present invention adopts a square-to-circular adapter pipe and a shrink pipe. The setting of the square-to-circle transfer pipe facilitates the connection between pipelines, and at the same time can effectively reduce the resistance loss in the water inlet section and reduce energy consumption; the shrink pipe adopts a uniformly reduced water cross-section and is connected tangentially with the straight pipe to accelerate the inlet flow rate, and then Increase the tangential swirl speed, increase the radial migration force in the device to promote the separation of two-phase media, and improve the separation efficiency of composite powder bio-carrier particles and bio-flocs.

2. There is a mutation point between the cylindrical section and the cone section or between the two cone sections of the traditional hydraulic cyclone, which can easily lead to instability of the fluid flowing through the mutation point, especially for composite powder biological carriers and bioflocs with small density differences. The fluid instability will cause the force to change, and some of the separated composite powder biological carrier particles will be mixed back and drawn into the central air column to escape from the overflow port, resulting in a decrease in screening efficiency. The present invention establishes a mathematical model of hydraulic sieving through the calculation of fine intermolecular forces; and conducts verification of orthogonal experiments on the screening and recovery of composite powder biological carrier particles and biological flocs through the 3D printing model of the inner cavity structure size obtained from the research. It is determined that the turbulent flow functional area of the present invention uses a cylindrical segment and a semi-ellipsoid segment structure to replace the traditional cylindrical structure, so that the connection port between the semi-ellipsoid segment and the conical surface segment can be in a tangent and continuous state of curvature, that is, the inner cavity of the semi-ellipsoid segment The inner cavity surface of curved surface and conical surface section is a continuous smooth surface. The fluid flows smoothly from the semi-ellipsoid section to the conical section under the action of swirling flow and gravity. The flow pattern is Stable and small resistance loss.

3. The present invention sets passive impellers in the cylindrical section and the semi-ellipsoid section, which rotates under the push of the imported mixed liquid. The denser composite powder biological carrier particles are pushed to the outer wall and separation area of the device under the spin of the impeller. The lighter density biofloc enters the central air column and is discharged through the overflow section, synchronously reducing the short flow and achieving a rectification effect, which strengthens the separation effect of the composite powder biocarrier particles and biofloc, and inhibits the separation of the separated composite powder. The biological carrier particles and biological flocs are back-mixed, which improves the screening efficiency; at the same time, the adhesion force between the attached and growing microorganisms based on the composite powder biological carrier particles is greater than the binding force between the suspended growth biological flocs, and the setting of the passive impeller can The size of the vortex in the swirl center is controlled within a small range to reduce the shear force of the water flow in the center, so that it can meet the separation conditions of the composite powder biological carrier particles and the biological floc particles without destroying the composite powder biological carrier particles. Adhesive structures between microorganisms on surfaces.

According to some embodiments of the present invention, the outer plate of the flow channel of the shrink tube has an arc structure, and its radius of curvature is D ₅ /2. The radius of the cylindrical section is D ₄ /2. The square opening of the shrink tube The width is B ₁ , where D ₅ /2 = D ₄ /2 + B ₁ , the end of the outer plate of the flow channel is connected tangentially to the top of the cylindrical section, and the inner plate of the flow channel of the shrink tube It is a straight plate structure. The inner plate of the flow channel and the arc surface of the semi-elliptical segment are connected vertically and tangentially on the left side. The water passing section of the flow channel of the shrink tube gradually shrinks from the square inlet at the upper end to the narrow one at the lower end. Square outlet, the pipe height of the shrink tube is H ₁ , H ₁ remains unchanged, the upper port width of the shrink tube is B ₁ , B ₁ is 0.2-0.25 times of D ₄ , and the cross-sectional width of the shrink tube is B ₂ and B ₂ /H ₁ are 0.25 to 0.45.

According to some embodiments of the present invention, the cylindrical section has a straight wall structure, D ₄ is 120 to 300 mm, the height of the cylindrical section is L ₁ , and L ₁ is 1.0 to 1.2 times H ₁ ; the semi-ellipsoid The inner cavity curved surface of the segment is a curved surface of revolution formed by rotating 360° around the central axis of the semi-ellipsoid segment with the edge segment of the semi-ellipsoid segment as the generatrix. The upper end of the semi-ellipsoid segment is in contact with the cylindrical segment. The lower end is vertically docked, and the lower end of the semi-ellipsoid segment is docked with the conical surface segment. The diameter of the docking point is the same, the diameter of the docking point is D ₁ , and D ₁ /D ₄ is 0.4 to 0.6.

According to some embodiments of the present invention, the side lines of the semi-ellipsoid segment are elliptical line segments with a major half-moment ratio and a short half-moment ratio a ₁ /b ₁ = 2 to 5. The upper end of the semi-ellipsoid segment is vertical, so The tangent angle of the lower end of the semi-ellipsoid section is 6° to 15°, the vertical height is L ₂ , and L ₂ is 120 to 300 mm.

According to some embodiments of the present invention, the cone curved surface segment is an inverted elliptical curved surface, that is, a curved surface of revolution that forms an internal cavity after rotating 360° around the central axis of the device with the edge of the cone curved surface segment as a generatrix. The upper end of the curved surface segment is docked with the semi-ellipsoid segment, and the connection between the two is in a tangent and continuous state of curvature. The tangential shrinkage angle of the connection is θ ₁ , and θ ₁ is 12° to 30°; the lower end of the conical surface segment is Underflow port, the diameter of the underflow port is 20-35mm, the contraction angle of the underflow port is θ ₂ , θ ₂ is 4°-10°; the height of the conical surface segment is L ₃ , L ₃ is 1000-1000 1500mm.

According to some embodiments of the present invention, the side lines of the conical surface segment are elliptical line segments with a major half-moment and a short half-moment ratio of a ₂ /b ₂ = 6 to 10. The angle between the tangent lines of the upper end of the conical surface segment is 6°～15°.

According to some embodiments of the present invention, the insertion depth of the lower insertion tube is H ₂ , and H ₂ is 0.4 to 0.7 times the sum of L ₁ and L ₂ .

According to some embodiments of the present invention, the passive impeller includes a blade assembly, a fixed disk and a hollow shaft, the hollow shaft is sleeved on the lower insertion tube, the blade assembly includes a sleeve and a plurality of blades, all The blade ring is arranged outside the sleeve, the length direction of the blade is arranged along the axial direction of the sleeve, and the sleeve is fixed on the hollow shaft through the fixing plate.

According to some embodiments of the present invention, the curvature of the outer edge of the blade is consistent with the curvature of the semi-ellipsoid segment, and the vertical distance from the bottom end of the blade to the entrance of the lower insertion tube is H ₃ , H ₃ It is 0.4~0.6 times of _L2 .

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

Figure 1 is a schematic structural diagram of a hydraulic screening device for low-density difference composite powder biological carrier particles according to an embodiment of the present invention;

Figure 2 is a top cross-sectional view of a hydraulic screening device for low-density difference composite powder biological carrier particles according to an embodiment of the present invention;

Figure 3 is a schematic structural diagram of the edge line of the semi-ellipsoid segment of the present invention;

Figure 4 is a schematic structural diagram of the edge line of the conical surface segment of the present invention;

Figure 5 is a schematic diagram of the assembly of the passive impeller;

FIG6 is a perspective view of a feed pipe;

FIG. 7 is a cross-sectional view of the feed pipe.

Reference number:
Feed pipe system 610; feed pipe 611; square-to-circle adapter pipe 612; shrink tube 613; outer wall plate 614; inner wall plate 615; cylindrical section 620; cylindrical section shell edge 621; top cover 622; semi-ellipsoid Section 630; semi-ellipsoid section edge 631; connection port 632; conical surface section 640; conical surface section edge 641; bottom flow port 642; overflow piping system 650; upper connecting tube 651; lower insertion tube 652; passive impeller 660; blade assembly into 661; fixed plate 662; hollow shaft 663.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and cannot be understood as limiting the present invention.

In the description of the present invention, it should be understood that the orientation descriptions involved, such as the orientation or position indicated by up, down, etc. The relationship is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does 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 It should not be construed as a limitation of the present invention.

In the description of the present invention, plural means two or more. If there is a description of first and second, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the order of indicated technical features. relation.

In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

Referring to Figures 1 to 7, the present invention discloses a low density difference composite powder biological carrier particle hydraulic screening device, including:

As shown in Figures 1 and 2, the feed pipe system 610, the cylindrical section 620, the semi-ellipsoid section 630, the conical surface section 640, the overflow pipe system 650 and the passive impeller 660; the feed pipe system 610 is located at the upper part of the device and is connected with the cylindrical section. The outer walls of the segments 620 are connected in cross section. A top cover 622 is provided above the cylindrical segment 620, and is connected to the semi-ellipsoid segment 630 below. The lower part of the semi-ellipsoid segment 630 is connected to the conical surface segment 640. The overflow pipe system 650 is fixedly installed in the center of the top cover of the upper part of the cylindrical section 620. The upper nozzle 651 is higher than the top cover 622 and is connected to the external mud discharge system. The lower insertion pipe 652 is located in the center of the cylindrical section 620 and the semi-ellipsoid section 630. position, and a passive impeller 660 is provided on the outside.

The feed pipe system 610 includes a feed pipe 611 , a square-to-circle adapter pipe 612 and a shrink pipe 613 . The feed nozzle 611 is a nozzle with a circular standard flange and is connected to the external feeding system. The circular interface at the outlet end of the feed nozzle 611 is consistent with the caliber of the round end of the square-to-round adapter pipe 612 and connected. The other end of the nozzle 612 has a square opening (ie, B ₁ =H ₁ ), and its cross-sectional area is equal to or slightly smaller than the round end, and is consistent with and connected to the diameter of the square opening of the shrink tube 613 . The shrinking tube 613 is a rectangular shrinking tube, and the water cross-section is a gradually shrinking arc-shaped flow channel structure.

The flow channel outer wall plate 614 of the shrink tube 613 has an arc structure, and its radius of curvature D ₅ /2 is the sum of the radius D ₄ /2 of the device cylindrical section 620 and the square opening width B ₁ of the shrink tube 613, that is, D ₅ / 2＝D ₄ /2+B ₁ , the end of the arc plate and the straight wall section are connected horizontally and tangentially at the top of the device. The inner plate of the flow channel is a straight plate structure, and is vertically tangential to the arc surface of the semi-ellipsoid section on the left connection. The water cross-section of the flow channel gradually shrinks from the square inlet at the upper end to the narrow square outlet at the lower end. The pipe height H ₁ of the shrink tube 613 remains unchanged, B ₁ is 0.2-0.25 times the diameter D ₄ of the cylindrical section 620, and the cross-section width of the outlet end is The high ratio B ₂ /H ₁ is generally 0.25~0.45, and the outlet flow rate should be controlled at 3~6m/s.

The cylindrical section 620 has a straight wall structure, and the diameter D ₄ is generally 120 to 300 mm. The height L ₁ of the cylindrical section 620 is 1.0 to 1.2 times the pipe height H ₁ of the shrink tube 613 . The inner cavity curved surface of the semi-ellipsoid section 630 is a curved surface of revolution formed by rotating 360° around the central axis of the device with the side line 631 of the semi-ellipsoid section as the bus line. The upper end of the semi-ellipsoid section 630 is vertically connected to the lower end of the cylindrical section 620, and the lower part is connected to the conical surface. Segments 640 are butt-jointed, the connecting port 632 has the same diameter, and the diameter D ₁ of the lower end of the semi-ellipsoid segment 630 is the same as that of the cylindrical segment. The 620 diameter D ₄ ratio should be 0.4 to 0.6.

As shown in Figures 1 and 3, the semi-ellipsoid segment side line 631 is the semi-ellipsoid segment side line 631 with the ratio of the major and minor half moments of the ellipse a ₁ /b ₁ = 2 to 5. The upper end is vertical and the lower end has a tangent angle of 6°. ~15°, the vertical height should be 120~300mm.

The cone surface segment 640 is an inverted elliptical surface, that is, the cone surface segment edge 641 is used as the busbar and is rotated 360° around the central axis of the device to form a revolution surface of the internal cavity. The upper end of the cone surface segment 640 is connected to the semi-ellipsoid segment 630. The connecting port 632 is in a tangent and continuous state of curvature, and the tangential shrinkage angle θ ₁ of the connecting port 632 is preferably 12° to 30°; the lower end of the conical surface section 640 is the bottom flow port 642, and the outlet diameter is preferably 20 to 35 mm, and the outlet shrinkage angle θ ₂ is 4°~10°; the height of the conical surface section 640 should be 1000~1500mm.

As shown in Figures 1 and 4, the conic surface segment edge 641 is an ellipse long half-moment, the short half-moment ratio is a ₂ /b ₂ = 6 to 10, and the upper end tangent angle is 6° to 15°. .

During the screening process, the mixed liquid of composite powder biological carrier particles and biological floc in the sewage treatment biochemical system with a concentration less than 15g/L and a density difference of 0.07~0.15g/ ^cm3 is discharged from the feed material under the action of the pump. The outlet of the shrink tube 613 of the piping system 610 enters the cylindrical section 620, and the flow rate at the outlet of the shrink tube 613 is controlled at 3 to 6 m/s. The mixed material entering the cylindrical section 620 separates the composite powder biological carrier particles from the biological floc under the action of turbulence and water flow shear force.

After the composite powder biological carrier particles are separated from the biofloc, the denser composite powder biological carrier particles will be enriched on the tube wall under the action of cyclone, and flow into the conical surface section along the tube wall under the action of gravity. 640 in. The lighter-density bioflocs are enriched at the outer edge of the air column, forming a transition zone between the tube wall and the air column. Finally, the composite powder biological carrier particles with higher density are recovered from the underflow port 642 under the action of gravity and centrifugal force, and returned to the biochemical system. The lighter density biological floc and sewage spiral upward, are discharged from the overflow pipe system 650, and enter the sludge discharge system.

It should be noted that the low-density-difference composite powder biological carrier particle hydraulic screening device of the present invention is suitable for screening and recovering a mixed liquid containing composite powder biological carrier particles and biological floc with a concentration of less than 15 g/L. When the concentration is higher than 15g/L, the "crowding effect" produced by the composite powder bio-carrier particles and bio-flocs in the cylindrical section 620 and the semi-ellipsoid section 630 is significantly enhanced, resulting in unsatisfactory separation of the composite powder bio-carrier particles and bio-flocs. .

Using the low-density difference composite powder biological carrier particle hydraulic screening device of the present invention, during use, according to the physical and chemical properties of the composite powder biochemical carrier and biological floc and the difference in turbulence and centrifugal force required in the screening and recovery process, the cylinder The diameter and length of the section 620, the semi-ellipsoid section 630, the conical surface section 640, the shrinkage ratio of the feed pipe system 610 and the insertion depth of the lower insertion pipe 652 of the overflow pipe system 650 can be set and adjusted to realize the composite The screening efficiency of powdered biological carrier particles reaches 80% to 90%, as shown in Table 1:

Table 1 Comparison table of the sieving efficiency of the hydraulic sieving device for low-density difference composite powder biological carrier particles of the present invention after optimizing the functional partitions and inner cavity structure and the size of the inner cavity structure other than the size of the inner cavity structure

It can be seen from the above table that the low density difference composite powder biological carrier particle hydraulic screening device of the present invention can separate the composite powder biological carrier particles and biological flocs with a density difference of only 0.07-0.15g/ ^cm3 , and the composite powder biological carrier particles The screening efficiency can reach 80% to 90%. Putting the screened composite powder biological carrier particles back into the sewage treatment tank can stabilize the content of the composite powder biological carrier during the sewage treatment process and reduce the dosage of powder biological carrier, which has significant economic value.

It should be explained that the cone section of the traditional hydraulic cyclone adopts a double-cone section straight cone design, and there is a mutation point between the two cone sections. When the pressure fluid flows through the cone section, it is subject to a reaction force perpendicular to the wall surface of the cone section. The reaction force will push the material obliquely upward toward the air column. Among them, the lighter-density biological flocs will migrate toward the air column, and the higher-density composite powder biological carrier particles will migrate downward under the action of centrifugal force and gravity. There is a mutation point in the double cone section, which causes the fluid flow pattern to become unstable and the force direction of the fluid to change. The force on the light material in the small cone section tends to be horizontal, which is not enough to offset the gravity effect, and will escape to the bottom flow port 642, resulting in The separation efficiency decreases; in addition, the existence of mutation points causes the fluid head loss to increase and energy consumption to increase. By using the semi-ellipsoid section 630 to replace the traditional cylindrical structure, the connection port 632 between the semi-ellipsoid section 630 and the conical surface section 640 can be in a tangent and continuous state of curvature, that is, the inner cavity surface of the semi-ellipsoid section 630 and the inner cavity surface of the conical surface section 640 can be realized The cavity surface is a continuous smooth surface, and the fluid flows smoothly from the semi-ellipsoid section to the cone section under the action of centrifugal force and gravity. The flow pattern is stable and the head loss is small.

Table 2 Effect of separation material concentration on screening efficiency when the inlet flow rate remains unchanged

It can be seen from Table 2 that when the inlet flow rate remains unchanged, the lower the separation material concentration, the better the separation effect. When the concentration increases, the "crowding effect" gradually increases, and the composite powder biological carrier particles and biological floc particles are not fully separated and directly escape through the overflow pipe system 650, resulting in a decrease in screening efficiency. This is particularly obvious when the material concentration exceeds 15g/L.

Referring to Figures 1, 2 and 5, a passive impeller 660 is also included. The passive impeller 660 is arranged in the cylindrical section 620 and the semi-ellipsoid section 630. The passive impeller 660 includes a blade assembly 661, a fixed disk 662 and a hollow shaft 663. , the hollow shaft 663 is rotatably installed on the lower insertion pipe 652 of the overflow piping system 650. The blade assembly 661 includes a sleeve and multiple blades. The multiple blades are ring-mounted outside the sleeve, and the blades are arranged along the axial direction of the sleeve. The sleeve is fixed on the hollow shaft 663 through the fixed plate 662. The curvature of the outer edge of the blade is consistent with the curvature of the semi-ellipsoid section. The height _H3 of the blade below the overflow pipe opening should be 0.4 to 0.6 of the height _L2 of the semi-ellipsoid section 630. times.

In the present invention, a passive impeller 660 is provided on the cylindrical section 620 and the semi-ellipsoid section 630. The passive impeller 660 rotates under the impetus of the inlet mixed liquid, and the denser composite powder biological carrier particles are pushed to the separation zone under the spin of the impeller. And dense The lighter biofloc enters the central air column and is discharged from the upper nozzle 651 of the overflow piping system, reducing the short flow in the cylindrical section 620 and the semi-elliptical section 630, achieving a rectification effect, and strengthening the interaction between the composite powder biological carrier particles and The separation effect of the biofloc suppresses the back-mixing of the separated composite powder biocarrier particles and the biofloc, thereby improving the screening efficiency; at the same time, the setting of the passive impeller 660 can control the vortex scale at the center of the semi-ellipsoid section 630 to a relatively small size. In a small range, the shearing force of the water flow in the center is reduced, so that it can satisfy the separation of the composite powder biological carrier particles and the biological floc particles without destroying the adhesion structure between the microorganisms on the surface of the composite powder biological carrier particles. It can be understood that in this embodiment, the passive impeller 660 is composed of a blade assembly 661, a fixed disk 662 and a hollow shaft 663. The hollow shaft 663 is rotatably installed on the lower insertion pipe 652 of the overflow piping system 650. The blade assembly 661 is clamped and fixed on the hollow shaft 663 through the fixed plate 662. By setting up a passive impeller, the screening efficiency of composite powder biological carrier particles can be increased to more than 95%.

Specifically, when sewage flows from the feed pipe system 610 into the cylindrical section 620, the water flow will push the impeller to rotate. When the material flows through the passive impeller 660, the denser composite powder biological carrier particles will migrate to the side wall under the action of self-rotation. , the lighter-density materials migrate to the central area, strengthening the separation of the composite powder biological carrier particles and the biological floc particles; the blades of the passive impeller 660 are enclosed in a cone shape, which can accelerate the enrichment of the denser composite powder biological carrier particles and improve Separation efficiency and reduced energy consumption. In addition, the setting of the passive impeller 660 can control the size of the vortex in the center of the semi-ellipsoid section 630 to a smaller range, reduce the velocity gradient of the fluid in the center, thereby reducing the shearing effect of the water flow in the center, so that it can meet the requirements of the composite powder. While the biological carrier particles are separated from the biological floc particles, the adhesion structure between microorganisms on the surface of the composite powder biological carrier particles is not destroyed.

It should be explained that if the insertion pipe 652 in the lower part of the overflow piping system is too short, it will cause a short flow effect; if it is too long, it will cause excessive energy consumption of the mixed liquid in the cylindrical section 620, resulting in insufficient separation kinetic energy in the later stage and a decrease in separation efficiency; both will The composite powder biocarrier particles are caused to escape from the overflow piping system 650 . Therefore, the height H ₂ of the lower insertion pipe 652 of the overflow piping system 650 is preferably 0.4 to 0.7 times the sum of the height L ₁ of the cylindrical section 620 and the height L ₂ of the semi-ellipsoid section 630 .

In this embodiment, a passive impeller 660 is provided. Driven by the material jet at the inlet of the feed pipe system 610, the blade assembly 661 drives the hollow shaft 663 to rotate regularly. Under the push of the blades, the composite biological carrier particle material is pushed outside the blades. The wall is enriched to reduce the loss from the overflow section, while reducing the short flow and improving the screening efficiency.

The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various modifications can be made without departing from the purpose of the present invention. Variety.

Claims

A hydraulic screening device for low-density difference composite powder biological carrier particles, which is characterized by including: a feed pipe system, a cylindrical section, a semi-ellipsoid section, a conical surface section, an overflow pipe system and a passive impeller;

Wherein, the feed pipe is connected to the outer wall section of the cylindrical section, a top cover is provided above the cylindrical section, the bottom is connected to the semi-ellipsoid section, and the bottom of the semi-ellipsoid section is connected to the conical surface. segment docking;

The overflow pipe system is fixedly installed in the center of the top cover on the upper part of the cylindrical section. The overflow pipe system is equipped with a lower insertion pipe and an upper nozzle. The upper nozzle is higher than the top cover and is used to communicate with the external mud discharge system. Connected, the lower insertion tube is located on the central axis of the cylindrical section and the semi-ellipsoid section, and the passive impeller is provided on the outside of the lower insertion tube.
The low-density difference composite powder biological carrier particle hydraulic screening device according to claim 1, characterized in that: the feed pipe system includes a feed pipe, a square-to-circle pipe and a shrink pipe;

Wherein, the feed nozzle is a nozzle with a circular standard flange for connecting to an external feed system. The circular interface of the water outlet end of the feed nozzle is consistent with the caliber of the round end of the square-to-round adapter pipe and is connected to each other. , the other end of the square-to-circle adapter pipe is a square port, its cross-sectional area is equal to or smaller than its round port end, and is consistent with the caliber of the square port of the shrink tube but connected, the shrink tube is a rectangular tapered tube, through The water cross section is a gradually shrinking arc-shaped flow channel structure.
The low-density difference composite powder biological carrier particle hydraulic screening device according to claim 2, characterized in that: the outer plate of the flow channel of the shrink tube is an arc structure, and its radius of curvature is D 5 /2, and the cylinder The radius of the segment is D 4 /2, and the width of the square opening of the shrink tube is B 1 , where D 5 /2=D 4 /2+B 1 , and the end of the outer plate of the flow channel and the end of the cylindrical section The top end is horizontally and tangentially connected. The inner plate of the flow channel of the shrink tube is a straight plate structure. The inner plate of the flow channel and the arc surface of the semi-ellipsoid segment are connected vertically and tangentially on the left side. The flow channel of the shrink tube is connected vertically and tangentially. The water passing section of the channel gradually shrinks from the square inlet at the upper end to the narrow square outlet at the lower end. The pipe height of the shrinkable tube is H 1 , H 1 remains unchanged, and B 1 is 0.2-0.25 times of D 4. The shrinkage tube The cross-sectional width of the tube is B 2 and B 2 /H 1 is 0.25 to 0.45.
The low density difference composite powder biological carrier particle hydraulic screening device according to claim 3, characterized in that: the cylindrical section has a straight wall structure, D4 is 120~300mm, and the height of the cylindrical section is L1 , L 1 is 1.0 to 1.2 times H 1 ; the inner cavity curved surface of the semi-ellipsoid segment is formed by rotating 360° around the central axis of the semi-ellipsoid segment with the side line segment of the semi-ellipsoid segment as the generatrix. Curved surface of revolution, the upper end of the semi-ellipsoid section is vertically connected to the lower end of the cylindrical section, the lower end of the semi-ellipsoid section is connected to the conical surface section, the diameter of the joint is the same, and the diameter of the joint is D 1 , D 1 /D 4 is 0.4 to 0.6.
The low-density-difference composite powder biological carrier particle hydraulic screening device according to claim 4, characterized in that: the side lines of the semi-ellipsoid segment are the long half-moment of the ellipse and the short half-moment ratio a 1 /b 1 =2～ 5, the upper end of the semi-ellipsoid segment is vertical, the tangent angle of the lower end of the semi-ellipsoid segment is 6° to 15°, the vertical height is L 2 , and L 2 is 120 to 300 mm.
The low-density composite powder biological carrier particle hydraulic screening device according to claim 1 is characterized in that: the conical surface segment is an inverse elliptical surface, that is, the edge line of the conical surface segment is used as the generatrix to rotate around the central axis of the device After rotating 360°, a revolving curved surface of the internal cavity is formed, the upper end of the conical surface segment is butt-jointed with the semi-ellipsoid segment, the connection port of the two is in a curvature tangent continuous state, the contraction angle of the tangent surface of the connection port is θ 1 , θ 1 is 12°～30°; the lower end of the conical surface segment is an underflow port, the caliber of the underflow port is 20～35mm, the contraction angle of the underflow port is θ 2 , θ 2 is 4°～10°; the height of the conical surface segment is L 3 , L 3 is 1000～1500mm.
The low-density-difference composite powder biological carrier particle hydraulic screening device according to claim 6, characterized in that: the side lines of the conical surface segment are ellipse long half moments, and the short half moment ratio is a 2 /b 2 =6～ 10 elliptical line segment, the angle between the tangent lines of the upper end of the conical surface segment is 6° to 15°.
The low density difference composite powder biological carrier particle hydraulic screening device according to claim 1, characterized in that: the insertion depth of the lower insertion tube is H 2 , and H 2 is 0.4 to 0.7 of the sum of L 1 and L 2 times.
The low-density difference composite powder biological carrier particle hydraulic screening device according to claim 1, characterized in that: the passive impeller includes a blade assembly, a fixed disk and a hollow shaft, and the hollow shaft is sleeved in the lower insertion tube On the above, the blade assembly includes a sleeve and a plurality of blades, all the blade rings are arranged outside the sleeve, the length direction of the blades is arranged along the axial direction of the sleeve, and the sleeve passes through The fixed plate is fixed on the hollow shaft.
The low density difference composite powder biological carrier particle hydraulic screening device according to claim 9, characterized in that: the curvature of the outer edge curve of the blade is consistent with the curvature of the semi-ellipsoid segment, and the bottom end of the blade reaches The vertical distance of the inlet of the lower insertion tube is H 3 , and H 3 is 0.4 to 0.6 times of L 2 .