Integrated high-density sedimentation tank with sludge external circulation

Abstract

The invention relates to the technical field of sewage treatment, and particularly discloses an integrated high-density sedimentation tank with sludge external circulation, which comprises a support bracket, a cavity, a water inlet pipe, a blow-off pipe and a partition plate, and is characterized in that a separation part is arranged outside the cavity, and the separation part generates eddy current in a separation shell through forward and reverse rotation of paddles, so that the separation part is separated from the water inlet pipe and the blow-off pipe; sludge is enriched and concentrated on the surface of the collecting piece, then high-density sludge is sent back to the top of the cavity through a return mechanism to form a sinking sediment blanket, and therefore the sedimentation process of sewage is accelerated, chemical flocculants do not need to be added, the sedimentation speed and efficiency are remarkably improved, and the operation cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and more specifically, to an integrated high-density sedimentation tank with external sludge circulation. Background Technology

[0002] In wastewater treatment, sedimentation tanks are common solid-liquid separation devices used to remove suspended particles, such as silt and organic matter, from wastewater through gravity settling. Traditional high-density sedimentation tanks mainly rely on the principle of natural settling, where heavier solid impurities gradually settle to the bottom during the settling process, thus achieving separation. However, this method has significant drawbacks: natural settling is slow and time-consuming, and its effectiveness is easily affected by water flow disturbances, temperature changes, or equipment vibrations, leading to an unstable sediment layer, resuspension, and reduced purification efficiency.

[0003] To address the issue of settling velocity, existing technologies often employ the addition of chemical flocculants (such as polyaluminum chloride or polyacrylamide) to promote particle flocculation and accelerate settling. While this method can increase the apparent settling velocity, it introduces new problems: chemical additives increase operating costs, may cause secondary pollution, and require additional reagent dosing and mixing equipment, complicating the system. Furthermore, chemical flocculants may alter the properties of the sludge, increasing the difficulty of subsequent treatment.

[0004] Another approach to improvement is to enhance settling through internal circulation or mechanical agitation, such as installing agitators or circulation pumps inside the sedimentation tank. However, these designs are often complex in structure, consume more energy, and can easily disturb the settled sludge layer, thus affecting the settling effect. Some equipment also suffers from drawbacks such as frequent maintenance and rapid wear, making it difficult to maintain stability during long-term operation.

[0005] In view of this, we propose an integrated high-density sedimentation tank with external sludge circulation to solve the problems mentioned in the background art.

[0006] This invention achieves sludge recycling, concentration, and return through an external separation unit. It utilizes the "sludge blanket" mechanism formed by its own sediment to significantly accelerate the sedimentation process and improve the stability of the sediment layer without relying on chemical additives. Summary of the Invention

[0007] The purpose of this invention is to provide an integrated high-density sedimentation tank with external sludge circulation to solve the problem of low settling efficiency of traditional sedimentation tanks mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides an integrated high-density sedimentation tank with external sludge circulation, comprising a support frame, a cavity fixedly installed on the top of the support frame, an inlet pipe disposed on the outer surface of the cavity, a drain pipe disposed at the bottom of the cavity, and a partition plate dividing the interior of the cavity into a stirring space and a settling space; a separation section is provided outside the cavity, the separation section comprising a separation shell, a paddle disposed inside the separation shell, and a collection element disposed in annularly on the inner wall of the separation shell; wherein, the paddle generates vortices inside the separation shell by rotating in the forward direction, the vortices colliding with the collection element, causing sludge and impurities in the sewage to accumulate on the surface of the collection element; when the paddle rotates in the reverse direction, the accumulated sludge and impurities fall off the surface of the collection element, which is used for external circulation concentration and return of sludge in the cavity to accelerate sewage sedimentation.

[0009] As a further improvement to this technical solution, the blades are driven by a rotating motor, which can generate vortices inside the separation shell, causing the sludge to be enriched and concentrated on the surface of the collecting element.

[0010] As a further improvement to this technical solution, the inner arc surface of the collecting component is provided with circumferentially distributed protrusions, and the surface of the protrusions has equally spaced stepped grooves. The tilting direction of the protrusions is opposite to the tilting direction of the blades, which is used to intercept and concentrate sludge solid impurities by centrifugal force.

[0011] As a further improvement to this technical solution, the separation unit also includes a return water pipe and a drain pipe that are connected to the separation shell. Both the return water pipe and the drain pipe are equipped with electrically controlled valves. By controlling the forward and reverse rotation of the paddle, the sludge enrichment mode and the cleaning mode can be switched. In the enrichment mode, the drain pipe is open and the return water pipe is closed, while in the cleaning mode, the return water pipe is open and the drain pipe is closed.

[0012] As a further improvement to this technical solution, the end of the return water pipe away from the separation shell is connected to a diverter, and the diverter is connected to multiple horizontally linearly distributed spray pipes. The outer arc surface of the spray pipe is provided with through holes, which are used to uniformly return the concentrated high-density sludge to the top of the cavity to form a sinking "sludge blanket".

[0013] As a further improvement to this technical solution, a diverter is connected to one end of the connecting pipe at the bottom of the cavity. The diverter is connected to multiple horizontally linearly distributed suction pipes. The bottom of the outer arc surface of the suction pipe is provided with a through hole for uniformly sucking sludge from the bottom of the cavity to avoid disturbing the sediment layer.

[0014] As a further improvement to this technical solution, the separation section is connected to the outer surface of the cavity via a vibration-damping telescopic rod. The telescopic end of the vibration-damping telescopic rod is fixed with an installation plate, which is fixedly connected to the separation shell to reduce the impact of vibration generated by the blade rotation on the sedimentation process inside the cavity.

[0015] As a further improvement to this technical solution, a stirring part is provided in the stirring space of the cavity. The stirring part includes a drive motor, a rotating arm, a swing arm and a stirring plate. The drive motor drives the rotating arm to rotate, and the swing arm drives the stirring plate to reciprocate in an arc shape under the constraint of the sliding limit member, so as to pre-stir the sewage.

[0016] As a further improvement to this technical solution, the bottom of the swing arm is provided with a sliding groove, and the sliding limiting member is slidably connected to the sliding groove to ensure that the movement trajectory of the stirring plate covers most of the stirring space and achieves uniform stirring.

[0017] As a further improvement to this technical solution, the external sludge circulation process accelerates sedimentation through a "sludge blanket" mechanism, in which the returned high-density sludge acts as a flocculant nucleus, capturing suspended particles during the settling process, achieving a combination of layered sedimentation and filtration, significantly improving the apparent sedimentation rate, and eliminating the need to add chemical flocculants.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This integrated high-density sedimentation tank with external sludge circulation significantly accelerates the settling speed of wastewater. Traditional sedimentation tanks rely on natural settling, which is time-consuming and easily affected by disturbance. This design, however, uses a vortex circulation mechanism in the separation section to draw sludge from the bottom of the chamber into the separation shell. The centrifugal force generated by the rotation of the paddles enriches and concentrates the sludge on the surface of the collection element. The concentrated high-density sludge is returned to the top of the chamber through the return water pipe, forming a uniformly falling "sludge blanket". The "sludge blanket" acts as a flocculant nucleus, capturing suspended particles during the settling process in the water. Through collision, adsorption, and filtration, free settling is transformed into stratified settling, greatly improving the settling speed.

[0019] 2. This integrated high-density sedimentation tank with external sludge circulation utilizes the sewage's own sludge for circulation and concentration, eliminating the need for chemical additives. The forward and reverse rotation of the paddles enables automated circulation of sludge enrichment and cleaning, reducing operating costs and maintenance frequency. At the same time, the multi-point distribution of spray pipes and suction pipes ensures uniform sludge return and suction. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure assembly of the present invention; Figure 2 This is a schematic diagram of the structure of the detachable shell in this invention; Figure 3 This is a schematic diagram of the structure of the collecting component in this invention; Figure 4 This is a schematic diagram of the suction tube in this invention; Figure 5 This is a schematic diagram of the stirring section in this invention.

[0021] The labels in the diagram represent the following: 1. Support bracket; 2. Cavity; 3. Inlet pipe; 4. Drain pipe; 5. Divider plate; 6. Stirring section; 61. Motor housing; 62. Rotating arm; 63. Swinging arm; 64. Sliding groove; 65. Sliding limiter; 66. Stirring plate; 7. Separation section; 71. Vibration damping telescopic rod; 72. Mounting plate; 73. Separation shell; 74. Connecting pipe; 75. Return water pipe; 76. Drain pipe; 77. Paddle; 78. Collector; 79. Spraying pipe; 710. Suction pipe. Detailed Implementation

[0022] The technical solutions in 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.

[0023] Example 1 Please see Figures 1-5 As shown, this embodiment provides an integrated high-density sedimentation tank with external sludge circulation, including a support bracket 1 and a cavity 2 fixedly installed on the top of the support bracket 1. The bottom of the cavity 2 is conical, and an inlet pipe 3 is provided through the outer surface of the cavity 2. A drain pipe 4 is provided through the bottom of the cavity 2.

[0024] By introducing sewage containing silt into the cavity 2 through the inlet pipe 3 and allowing the sewage to stand in the cavity 2 for a long time, the lighter water in the sewage is separated from the heavier solid silt impurities. The heavier solid silt impurities accumulate at the bottom of the cavity 2 and are discharged from the drain pipe 4 at the bottom, thereby allowing the clearer water to be retained in the cavity 2 for further use or filtration. However, in the use of traditional sedimentation tanks, due to the large internal space of the chamber 2 used to store liquid, it takes a long time for the water and silt in the sewage to be completely separated. Moreover, the silt after separation floats at the bottom of the sewage. When the sewage is agitated or flows, the silt settled at the bottom will be stirred up again, which reduces the effect of sediment separation in the sewage during the process of discharging the sediment at the bottom. To accelerate the settling of wastewater inside the cavity 2 and prevent the settled sludge layer from splashing again, a separation section 7 is fixedly provided on the outer surface of the cavity 2. The separation section 7 includes a connecting pipe 74 that is connected through and conductive to the bottom side of the cavity 2. The other end of the connecting pipe 74 is conductively connected to a separation shell 73. The separation shell 73 is circular, and a paddle 77 is rotatably installed inside the separation shell 73. An annular collection element 78 is installed inside the separation shell 73. A drain pipe 76 is conductively connected to the end of the separation shell 73 away from the connecting pipe 74. The other end of the drain pipe 76 extends into the cavity 2. A rotating motor for driving the paddle 77 to rotate is fixedly installed on the outside of the separation shell 73. Furthermore, the inner arc surface of the collector 78 is provided with circumferentially distributed protrusions, the protrusions are inclined in the opposite direction to the inclination direction of the blade 77, and the surface of the protrusions is provided with equally spaced stepped grooves. By rotating the motor to drive the blade 77 to rotate, a vortex is generated inside the separation shell 73. The vortex reduces the pressure inside the separation shell 73, which in turn allows the connecting pipe 74 to draw sewage with a high silt content from the bottom of the cavity 2 into the separation shell 73. Driven by the blade 77, the vortex rotates and flows inside the separation shell 73, causing the water flow to impact the protruding structure of the collection member 78. This results in the silt and other solid impurities in the water remaining on the surface of the collection member 78 and accumulating there. The drain pipe 76 allows the relatively clear sewage to flow back into the cavity 2. This circulation method allows silt and other solid impurities to remain inside the separation shell 73. Specifically, the principle of reducing the internal pressure of the separation shell 73 by generating eddies through the rotation of the blade 77, and the principle of the collection element 78 intercepting solid impurities such as mud and sand are disclosed: Before the blade 77 rotates, liquid needs to be manually added to the inside of the separation housing 73 to fill it with liquid. When the blade 77 is rotated by the motor, the liquid between the blades is thrown towards the outer edge of the impeller under the action of centrifugal force. The liquid gains kinetic energy and velocity and is thrown towards the pump casing. The liquid in the central area of ​​the impeller is thrown away, forming a low-pressure zone. During this stage, the water and silt in the sewage are subjected to centrifugal force. Since the density of solid silt impurities is greater than that of water, the centrifugal acceleration they experience is greater than that of water. As a result, the silt is thrown away from the center of the separation housing 73 to a greater extent than the water. When the solid silt impurities come into contact with the inner arc surface protrusion of the collection component 78, the solid silt impurities are bound by the groove structure of the protrusion surface. Subsequently, driven by the pressure difference between the low pressure inside the pump and the external atmospheric pressure, the liquid from the water source is continuously "push" into the pump, achieving the effect of sucking the sewage from the sludge area at the bottom of the cavity 2 into the separation housing 73. The principle of intercepting silt and solid impurities by the collector 78 is that the tilt angle of the protrusion is opposite to that of the blade 77. Therefore, as the water flow is driven by the blade 77 and rotates and flows inside the separation shell 73, the solid impurities thrown by centrifugal force collide with the inner arc protrusion surface of the collector 78. Furthermore, because the groove limits the solid impurities, the solid impurities that enter later squeeze the solid impurities that were previously inside the groove. This process causes the silt and solid impurities to accumulate on the surface of the collector 78 and gradually increase the density of the solid impurities.

[0025] The above process enables the sediment and impurities to be enriched and concentrated inside the separation shell 73, forming sediment and impurities with higher density. In order to achieve the purpose of accelerating the settling efficiency of sewage, the concentrated sediment particles need to be reintroduced into the cavity 2. Therefore, a return water pipe 75 is connected to the side of the separation shell 73 away from the rotating motor, and both the return water pipe 75 and the drain pipe 76 are equipped with electrically controlled valves. By setting a return water pipe 75 located at the center, when the paddle 77 rotates in the opposite direction, the concentrated silt and sand solid impurities can be separated from the surface of the collector 78 and flow back into the cavity 2 along the return water pipe 75. After returning to the cavity 2, these high-density silt particles form a "silt blanket" and fall evenly. During the falling process, the high-density silt can act as flocculation nuclei, which makes it easier for the suspended silt impurities in the sewage to accumulate on the surface of the high-density silt particles, thereby accelerating the sedimentation speed of silt in the sewage and realizing the efficiency of sewage settling and stratification by utilizing the structure of the silt itself.

[0026] Specifically, the principle by which high-density sediment causes suspended sediment impurities to quickly aggregate and settle is disclosed: When the concentrated, high-density sludge falls from the top of chamber 2, its descent can be approximated as a uniform descent of a "sludge blanket." During this process, tiny flocs and colloidal particles in the water that are not yet fully grown or broken frequently collide, contact, and are adsorbed by the large, mature flocs densely distributed in the sludge blanket. This is equivalent to adding an extra, highly efficient flocculation reaction zone during sedimentation, allowing tiny particles to be rapidly captured and "grown" onto the flocs of the sludge blanket, thus being removed from the water. The dense sludge blanket itself forms a physical barrier, its structure similar to the filter media layer of a deep filter (such as a sand filter). The rising water flow must pass through the tiny pores between the sludge particles. Particles larger than the pore size are directly mechanically screened and retained; even smaller particles are adsorbed onto the surface of the sludge particles through inertial collisions and diffusion. This process effectively removes fine suspended solids that are difficult to settle using traditional sedimentation methods. The high-density silt particles in the "sludge blanket" have a porous structure. When water flows through, these porous structures can capture small particles in the water like a "fishing net." At the same time, the high-speed upward flow of water has a relatively weak scouring effect on the bottom of the sludge blanket, but the sludge blanket as a whole is in a suspended state, which can produce a good sweeping effect on the particles in the water flow, carrying them into the interior of the blanket layer. In traditional horizontal or radial flow sedimentation tanks, separation mainly relies on the free settling of individual flocs, which is slow and ineffective at removing fine particles. However, the "sludge blanket" process in high-density sedimentation tanks transforms free settling into a combination of layered settling and filtration. Particles do not settle to the bottom alone but are "forced" to be removed as they pass through the sludge blanket, thus significantly increasing the apparent speed of settling and separation. Furthermore, compared to silt that settles naturally to the bottom, silt with high-density crystal nuclei is less affected by buoyancy after settling to the bottom due to its higher average density. This makes it less likely for the silt settled at the bottom to be stirred up when the sewage is agitated, thus ensuring stable settling results. To ensure that high-density sediment can be smoothly detached from the surface of the collector 78, it is also necessary to disclose the principle by which the blades 77 reverse to discharge the high-density sediment from the return water pipe 75: When the sediment is in the sediment enrichment stage, the electric valve of the return water pipe 75 is closed and the electric valve of the drain pipe 76 is open. The drain pipe 76 and the connecting pipe 74 form a loop, which achieves the effect of enriching sediment impurities inside the separation shell 73. Then, the electric valve of the drain pipe 76 is closed and the electric valve of the return water pipe 75 is opened, and the rotating motor is reversed, which in turn drives the blade 77 to reverse. The reverse blade 77 generates a vortex in the opposite direction to the forward rotation. This makes the sediment impurities that were washed and squeezed into the raised grooves on the surface of the collecting part 78 during the forward rotation no longer subject to the washing and squeezing force. Under the reverse washing of the vortex, they gradually loosen and fall off the surface of the collecting part 78. During this process, high-density sediment impurities are mixed into the reverse rotating vortex and eventually flow back into the cavity 2 from the return water pipe 75. By changing the direction of the vortex inside the separation shell 73, it is possible to switch from enriching silt and impurities inside the separation shell 73 to cleaning the silt and impurities enriched inside the separation shell 73. Furthermore, the silt and impurities present in the wastewater itself are used to accelerate sedimentation, avoiding the addition of flocculants or other reagents that are not originally present in the wastewater. This reduces purification costs and avoids introducing new sources of pollution into the wastewater.

[0027] The above structure enables the present invention to accelerate the settling efficiency of sewage inside cavity 2. To ensure the completeness of the solution, other structures of the separation section 7 are disclosed here: The connecting pipe 74 is connected to a diverter at one end of the bottom of the cavity 2. The diverter is connected to several horizontally arranged linearly and equally spaced suction pipes 710. The bottom of the outer arc surface of the suction pipe 710 is provided with a through hole facing the bottom of the cavity 2. The combination of the diverter and the suction pipes 710 can uniformly suck up the mud and sand layer deposited at the bottom of the cavity 2 when the blade 77 rotates. The multi-point synchronous suction method can reduce the water flow intensity generated during the suction process, thereby preventing the mud and sand layer deposited at the bottom from being stirred up during the suction process. Furthermore, a diverter is provided at the end of the return water pipe 75 away from the separation shell 73. The diverter is connected to several horizontally distributed spray pipes 79 at equal intervals. The bottom of the outer arc surface of the spray pipe 79 is provided with a through hole facing the bottom of the cavity 2. Through the diverter and the spray pipes 79, the high-density silt particles can be evenly dispersed in the internal space of the cavity 2 during the process of sewage returning to the top of the cavity 2, thereby ensuring that the "silt blanket" can be generated and evenly distributed. This increases the contact between the high-density silt particles and the suspended silt impurities in the sewage during the settling process, ensuring that the settling process is fully accelerated. To prevent the vibration generated by the rotation of the blade 77 from affecting the settling results inside the cavity 2, several vibration damping telescopic rods 71 ​​are fixedly installed on the outer surface of the cavity 2. The telescopic ends of the vibration damping telescopic rods 71 ​​are fixedly connected to the mounting plates 72, and the mounting plates 72 are fixedly connected to the separation shell 73. Through the structure of the vibration damping telescopic rods 71, the rotation vibration can be prevented from being transmitted to the cavity 2 during the rotation of the blade 77 driven by the rotating motor, thereby ensuring that the settling progress inside the cavity 2 is not affected by vibration.

[0028] To ensure that the sediment is evenly distributed in the sewage inside the cavity 2, the sewage needs to be pre-stirred before settling. Therefore, a partition plate 5 is sealed inside the cavity 2. The partition plate 5 divides the cavity 2 into two spaces: a stirring space that is directly connected to the water inlet pipe 3 and a sewage settling space. The partition plate 5 has through holes, the height of which is higher than the height of the water inlet pipe 3. A stirring part 6 is provided in the stirring space. By pre-stirring the wastewater, when the wastewater enters the settling space through the through holes on the partition plate 5, the sediment inside is already evenly distributed in the wastewater under the stirring action. The evenly distributed sediment impurities can reduce the probability of them clumping in the wastewater and ensure that they are in full contact with the sinking "sand blanket" during the subsequent accelerated settling process, thereby ensuring a complete accelerated settling and purification effect on the wastewater inside the cavity 2.

[0029] To ensure the completeness of the disclosure of this plan, the specific structure of the stirring unit 6 also needs to be disclosed: The stirring unit 6 includes a motor housing 61 fixedly disposed on the outer surface of the cavity 2. A drive motor is disposed inside the motor housing 61. The output end of the drive motor passes through the side of the cavity 2 and is fixedly mounted with a rotating arm 62. The rotating arm 62 is rotatably connected to the inner wall of the cavity 2. A swing arm 63 is rotatably disposed at the end of the rotating arm 62 away from the drive motor. A sliding groove 64 is disposed through the bottom of the swing arm 63. A sliding limit member 65 is fixedly disposed on the inner wall of the cavity 2. The sliding limit member 65 is slidably connected to the inner wall of the sliding groove 64. A stirring plate 66 is rotatably disposed at the bottom of the swing arm 63. The rotating arm 62 is continuously rotated by the drive motor, which can drive the stirring plate 66 to perform a reciprocating arc swing motion under the combination of the sliding limit member 65 and the swing arm 63, thereby stirring and processing the sewage flowing in from the inlet pipe 3. As the sewage enters the stirring space, the liquid level inside the stirring space rises. Finally, the stirred sewage enters the settling space through the through hole above the partition plate 5.

[0030] At the start of operation, wastewater flows into the mixing space from the inlet pipe 3. The drive motor starts, causing the rotating arm 62 to rotate continuously. The rotation of the rotating arm 62 is transmitted through the swing arm 63: due to the constraint of the sliding through groove 64 by the sliding limit member 65, the swing arm 63 generates a compound motion under the drive of the rotating arm 62, namely, the swing around the hinge point superimposed with linear sliding. This forces the mixing plate 66 to reciprocate in an arc shape around the center of the cavity 2, with the swing amplitude covering most of the mixing space. The swing of the mixing plate 66 generates shearing and eddy currents on the wastewater, breaking the static state of the silt particles and making them uniformly suspended in the water. During the process, the wastewater level gradually rises, and when the level exceeds the through hole on the partition plate 5, the stirred wastewater overflows into the static space; In the settling space, the separation unit 7 is activated to accelerate sedimentation. The separation unit 7 includes a separation shell 73, which is connected to the bottom of the cavity 2 via a connecting pipe 74. The end of the connecting pipe 74 is equipped with a diverter and multiple suction pipes 710 for uniformly sucking up the sludge from the bottom. The paddle 77 rotates forward under the drive of a rotating motor, generating a vortex inside the separation shell 73, which reduces the pressure and thus sucks up high-concentration sludge from the bottom of the cavity 2. In the vortex, the sludge and sand solids, due to their higher density, are thrown towards the collection element 78 by centrifugal force. The convex and stepped groove structure on the inner arc surface of the collection element 78 intercepts and enriches the sludge and sand, forming concentrated sludge; at the same time, the clearer water flows back to the cavity 2 through the drain pipe 76. When the separation section 7 switches to the cleaning mode, the paddle 77 reverses direction, changing the vortex direction and causing the high-density sludge accumulated on the surface of the collection element 78 to detach and be evenly returned to the top of the cavity 2 through the return water pipe 75 and the spray pipe 79 at its end. During the settling process, this high-density sludge forms a "mud blanket," acting as flocculant nuclei to capture suspended microparticles in the water, accelerating sedimentation through collision, adsorption, and filtration. This not only increases the settling speed but also makes the settled sludge denser and less prone to being disturbed and lifted. Throughout the process, the vibration-damping telescopic rod 71 supports the separation shell 73, reducing the interference of vibration on the settling within the cavity 2. Finally, the settled sludge is discharged through the drain pipe 4, while the purified water can be further utilized. This circular design avoids the need for external flocculants, reduces costs, and achieves efficient and stable sedimentation through a "sludge blanket" mechanism.

[0031] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. An integrated high-density sedimentation tank with sludge external circulation, comprising a support bracket (1), a cavity (2) fixedly installed on the top of the support bracket (1), a water inlet pipe (3) arranged on the outer surface of the cavity (2), a sewage discharge pipe (4) arranged at the bottom of the cavity (2), and a partition plate (5) separating the cavity (2) into a stirring space and a standing space, characterized in that: a separation part (7) is arranged outside the cavity (2), the separation part (7) comprises a separation shell (73), a paddle (77) arranged inside the separation shell (73), and a collecting piece (78) arranged annularly on the inner wall of the separation shell (73); wherein the paddle (77) generates vortex flow inside the separation shell (73) through forward rotation, the vortex flow collides with the collecting piece (78), and the sludge impurities in the sewage are enriched on the surface of the collecting piece (78); when the paddle (77) rotates reversely, the enriched sludge impurities fall off from the surface of the collecting piece (78), and are used for external circulation concentration and return of the sludge in the cavity (2), so as to accelerate the sedimentation of the sewage. The paddle (77) is driven by a rotating motor, and the paddle (77) can generate vortex flow inside the separation shell (73), so as to enrich and concentrate the sludge on the surface of the collecting piece (78). The inner arc surface of the collecting piece (78) is provided with circumferentially distributed protrusions, the surface of the protrusions is provided with equidistant stepped grooves, the inclined direction of the protrusions is opposite to the inclined direction of the paddle (77), and the sludge solid impurities are intercepted and concentrated through centrifugal force. The separation part (7) further comprises a backwater pipe (75) and a drain pipe (76) in conductive connection with the separation shell (73), the backwater pipe (75) and the drain pipe (76) are both provided with electric control valves, the sludge enrichment mode and the cleaning mode are switched by controlling the forward and reverse rotation of the paddle (77), the drain pipe (76) is opened and the backwater pipe (75) is closed in the enrichment mode, and the backwater pipe (75) is opened and the drain pipe (76) is closed in the cleaning mode.

2. The integrated high-density settling tank with sludge external circulation according to claim 1, characterized in that: The end of the backwater pipe (75) away from the separation shell (73) is connected with a flow divider, the flow divider is through-connected with a plurality of horizontally linearly distributed spray pipes (79), the outer arc surface of the spray pipe (79) is provided with through holes, and the concentrated high-density sludge is uniformly returned to the top of the cavity (2).

3. The integrated high-density settling tank with sludge external circulation according to claim 2, characterized in that: The end of the connecting pipe (74) at the bottom of the cavity (2) is connected with a flow divider, the flow divider is through-connected with a plurality of horizontally linearly distributed suction pipes (710), the outer arc surface of the suction pipe (710) is provided with through holes at the bottom, and the sludge is uniformly sucked from the bottom of the cavity (2), so as to avoid disturbance of the sedimentation layer.

4. The integrated high-density settling tank with sludge external circulation according to claim 3, characterized in that: The separation part (7) is connected with the outer surface of the cavity (2) through a damping telescopic rod (71), the telescopic end of the damping telescopic rod (71) is fixedly provided with a mounting plate (72), the mounting plate (72) is fixedly connected with the separation shell (73), and the influence of the vibration generated by the rotation of the paddle (77) on the sedimentation process in the cavity (2) is reduced.

5. The integrated high-density settling tank with sludge external circulation according to claim 4, characterized in that: ​ 6. The integrated high-density settling tank with sludge external circulation according to claim 5, characterized in that: ​ 7. The integrated high-density settling tank with sludge external circulation according to claim 6, characterized in that: ​ 8. The integrated high-density settling tank with sludge external circulation according to claim 7, characterized in that: The stirring space in the cavity (2) is provided with a stirring part (6), which comprises a driving motor, a rotating arm (62), a swinging arm (63) and a stirring plate (66). The rotating arm (62) is driven to rotate by the driving motor, so that the swinging arm (63) drives the stirring plate (66) to reciprocatingly swing in an arc shape under the constraint of a sliding limiting piece (65), and sewage is pre-stirred.

9. The integrated high-density settling tank with sludge external circulation according to claim 8, characterized in that: The swinging arm (63) is provided at the bottom with a sliding through groove (64), and the sliding limiting piece (65) is in sliding connection with the sliding through groove (64), so that the movement track of the stirring plate (66) covers most of the stirring space, and uniform stirring is realized.

10. The integrated high-density settling tank with sludge external circulation according to claim 9, characterized in that: The sludge external circulation process accelerates the sedimentation through a "mud blanket" mechanism, in which the returned high-density sludge acts as a flocculation nucleus to capture suspended particles during the sinking process, realizes the combination of laminar sedimentation and filtration, significantly improves the apparent sedimentation speed, and does not need to add chemical flocculants.

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