Coagulative precipitation tank for treating low-turbidity water

Abstract

The invention relates to the technical field of water treatment, and discloses a coagulative precipitation tank for low-turbidity water treatment, the coagulative precipitation tank comprises a precipitation tank, a driving assembly, a central shaft, a turbulent flow assembly and a sludge discharge assembly, the central shaft is vertically suspended along the central axis of the precipitation tank and is driven by the top driving assembly to reciprocate up and down; the turbulent flow assembly on the upper portion of the center shaft is provided with variable cross-section circular-truncated-cone-shaped turbulent flow holes, diffusion wake flow vortexes and contraction micro jet flow are generated through the fluid diode effect, low-shear efficient flocculation is achieved, a piston head at the bottom of the center shaft is matched with a sludge discharging pipe and an external check valve, and volumetric automatic sludge discharging is achieved through reciprocating pressure difference. Pressure waves are prevented from interfering bottom precipitation. According to the invention, mixing of the reaction zone and sludge discharge of the settling zone are realized through cooperation of a single power source, the structure is simplified, floc breaking is avoided, and cooperative control of flocculation mixing of the reaction zone and sludge discharge of the settling zone is realized while energy consumption and failure rate of equipment are reduced.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, specifically to a coagulation sedimentation tank for treating low-turbidity water. Background Technology

[0002] In water treatment and advanced industrial wastewater treatment processes, coagulation and sedimentation are the core steps for removing suspended solids, colloidal particles, and reducing turbidity in water. This is especially true for low-turbidity water, where the low particle concentration and low probability of collision result in loose and fragile flocs that are extremely sensitive to hydraulic conditions. Existing coagulation and sedimentation equipment typically uses a rotary mechanical mixer for mixing and reaction, along with a bottom scraper or sludge pump for sludge discharge.

[0003] However, traditional rotary agitation methods tend to generate a high shear flow field at the blade edge, which not only consumes a lot of energy but also easily breaks up the newly formed loose flocs, making sedimentation and separation difficult and resulting in unstable effluent quality.

[0004] Furthermore, to achieve independent control of the mixing and sludge removal functions, existing equipment requires multiple independent power drive systems and transmission mechanisms. For example, a mixing motor and reducer are installed at the top, while an underwater scraper or suction pump is installed at the bottom. This decentralized arrangement makes the equipment structure complex and increases the system's energy consumption.

[0005] While some technologies attempt to reduce shear forces by employing vertical flow or pulsed hydraulic agitation, achieving both high-efficiency reaction and high-concentration sludge discharge simultaneously in a single device still faces a contradiction in fluid dynamics. If vertical reciprocating motion is used to drive sludge discharge or agitation, the piston effect will generate strong pressure fluctuations at the bottom of the tank. These fluctuations are easily transmitted upwards and disrupt the laminar flow state in the sedimentation zone, causing the settled sludge to be resuspended and affecting the effluent quality.

[0006] Therefore, this invention proposes a coagulation sedimentation tank for treating low-turbidity water to overcome the shortcomings of the prior art. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a coagulation sedimentation tank for low-turbidity water treatment. It solves the problems of high shear force in rotary stirring, which easily leads to the breakage of loose flocs with low turbidity; independent driving of reaction and sludge discharge components, which leads to complex equipment structure; and the fluid pressure waves generated by traditional vertical motion, which easily interfere with the bottom sedimentation zone and cause sludge backmixing.

[0008] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a coagulation sedimentation tank for treating low-turbidity water, comprising a sedimentation tank, an inlet pipe, an outlet weir, and a drive assembly. The upper part of the sedimentation tank is configured as a cylindrical reaction zone, and the lower part is configured as a conical sedimentation zone.

[0009] The drive assembly is located at the top of the sedimentation tank and is connected to a central shaft that is vertically suspended along the central axis of the sedimentation tank. The central shaft is constrained to reciprocate only vertically. A flow-disrupting assembly is fixedly connected to the portion of the central shaft located in the reaction zone. The flow-disrupting assembly includes multiple layers of flow-disrupting plates spaced apart along the axial direction, and the flow-disrupting plates are configured to reciprocate vertically synchronously with the central shaft.

[0010] A sludge discharge assembly is fixedly connected to the center of the bottom of the sedimentation tank. The sludge discharge assembly includes a sludge discharge pipe and a piston head movably connected inside the sludge discharge pipe. The piston head is fixedly connected to the bottom end of the central shaft and reciprocates vertically synchronously with the central shaft. A check valve is installed inside the sludge discharge pipe, below the piston head.

[0011] Furthermore, in the reaction flocculation stage, this invention enhances the mixing effect through a pore structure utilizing fluid dynamics principles. The baffle plate has several frustum-shaped baffle holes extending through its surface. Each baffle hole has an upper opening on the upper surface of the baffle plate and a lower opening on the lower surface of the baffle plate, with the diameter of the upper opening being larger than that of the lower opening. The inner wall of the baffle hole smoothly transitions from the lower opening to the upper opening in a flared shape, forming a fluid channel with a constant cone angle.

[0012] When the baffle moves downward with the central axis, the fluid enters from the small-diameter end and flows out from the large-diameter end. The baffle holes form a diffusion channel, inducing the fluid to generate boundary layer separation and form a low-speed wake vortex, promoting micro-particle collision and flocculation. When the baffle moves upward, the fluid enters from the large-diameter end and flows out from the small-diameter end. The baffle holes form a converging nozzle, generating micro-jet to cut and mix the interlayer water.

[0013] Furthermore, to isolate the impact of upper mechanical vibration on the lower sedimentation environment, a flow stabilizing component is provided below the reaction zone in the sedimentation tank. The flow stabilizing component includes multiple layers of partition plates fixed to the inner wall of the sedimentation tank, and the partition plates are slidably connected to the central shaft.

[0014] The separator is made of an elastic material, and its surface has several honeycomb-shaped holes. This structure utilizes the physical barrier of the multi-layer separator and the elastic deformation of the material to dampen and weaken the pressure waves generated by the reciprocating motion of the upper turbulence component, while allowing flocs to settle into the sedimentation zone through the honeycomb holes.

[0015] Furthermore, this invention utilizes the principle of volume displacement to achieve quantitative discharge of high-concentration sludge from the bottom. The inner diameter of the sludge discharge pipe is larger than the outer diameter of the piston head, and an elastic scraper sealing ring is fixedly connected to the outer side of the piston head. This elastic scraper sealing ring forms a sliding seal contact with the inner wall of the sludge discharge pipe. The sludge discharge pipe has a straight-through structure and extends to the outside of the sedimentation tank. The check valve is located in the non-submerged area where the sludge discharge pipe extends to the outside of the sedimentation tank.

[0016] The direction of the check valve is opposite to that of the sedimentation tank, and it forms a pressure interlock logic with the movement of the piston head: when the piston head moves upward in the sludge discharge pipe, a negative pressure is formed in the pipe, the check valve closes, and the external sludge is sucked into the sludge discharge pipe. When the piston head moves downward, positive pressure is formed inside the pipe, and the check valve opens to discharge the accumulated sludge.

[0017] Furthermore, to optimize the hydraulic conditions of the incoming water and prevent the bottom sediment from being eroded, the inlet pipe is fixedly connected to the lower part of the sedimentation tank and located above the sedimentation zone. A guide plate is fixedly connected to the outlet end of the inlet pipe inside the sedimentation tank via a connecting rod. The guide plate is located on the central axis of the outlet end of the inlet pipe and has a conical structure. Together with the guide channel formed between adjacent connecting rods, it converts the horizontal momentum of the incoming water into a uniformly distributed upward flow.

[0018] Furthermore, to ensure uniform effluent flow, a baffle plate is fixedly connected to the top of the sedimentation tank. The upper part of the baffle plate has a ring-shaped, serrated structure for cutting and diverting the supernatant and intercepting floating debris. The effluent weir is fixedly connected to the upper outer side of the sedimentation tank and connected to the effluent pipe.

[0019] Furthermore, considering the potential eccentricity error that may occur with long-shaft transmission, a smoothly transitioning guide slope is provided at the top opening of the sludge discharge pipe, and the inner surface of the conical structure at the bottom of the sedimentation tank smoothly connects with the guide slope of the sludge discharge pipe. When the piston head descends and contacts this area, the guide slope provides physical constraint, forcibly guiding the piston head back to the central axis of the sludge discharge pipe.

[0020] This invention provides a coagulation sedimentation tank for treating low-turbidity water. It has the following beneficial effects: 1. This invention drives the central shaft to reciprocate vertically via a drive component, causing the upper turbulence-discharging component and the lower sludge discharge component to operate synchronously. This linkage structure eliminates the independent rotary mixer and bottom scraper found in traditional equipment, simplifies the complex underwater transmission mechanism, and reduces equipment energy consumption and failure rate while achieving coordinated control of flocculation mixing in the reaction zone and sludge discharge in the sedimentation zone.

[0021] 2. This invention incorporates frustum-shaped flow-dispersing holes on a flow-dispersing plate, utilizing the difference in flow resistance as the fluid flows through the variable cross-section channels in different directions to generate specific hydrodynamic effects. As the fluid flows downwards along the central axis, diffusion generates large-scale wake vortices, promoting effective collisions of microparticles; as it flows upwards, contraction generates microjet streams, eliminating short-flow dead zones between layers. This design enhances micro-mixing under non-rotational shear conditions, effectively improving reagent reaction efficiency and preventing the breakage of already formed flocs.

[0022] 3. This invention incorporates a flexible flow stabilizing component and an external sludge discharge check valve, solving the technical challenge of vertical motion interfering with sedimentation. The multi-layered elastic partition plates weaken the pressure waves generated by the reciprocating motion of the central axis through physical barriers and elastic deformation, maintaining a stable flow state in the bottom sedimentation zone. The external check valve, working in conjunction with the piston head, utilizes differential pressure logic to achieve automatic sludge discharge. Attached Figure Description

[0023] Figure 1 This is a perspective view of the present invention; Figure 2 This is a schematic diagram of the driving component in this invention; Figure 3 This is a schematic diagram of the structure of the turbulence component in this invention; Figure 4 This is a schematic diagram of the spoiler structure in this invention; Figure 5 This is a schematic diagram of the structure of the medium current stabilization component of the present invention; Figure 6 This is a schematic diagram of the sludge removal assembly in this invention; Figure 7 for Figure 6 Enlarged view of point A in the middle; Figure 8 This is a schematic diagram of the flow guide plate in this invention.

[0024] Legend 1. Sedimentation tank; 2. Slag baffle; 3. Effluent weir; 4. Inlet pipe; 5. Outlet pipe; 6. Sludge discharge pipe; 7. Drive assembly; 71. Mounting bracket; 72. Hydraulic cylinder; 73. Central shaft; 8. Flow turbulence assembly; 81. Flow turbulence plate; 82. Flow turbulence hole; 9. Flow stabilization assembly; 91. Partition plate; 92. Honeycomb hole; 10. Sludge discharge assembly; 101. Sludge discharge pipe; 102. Check valve; 103. Piston head; 104. Elastic sludge scraper sealing ring; 11. Connecting rod; 12. Guide plate. Detailed Implementation

[0025] 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.

[0026] Please see Figure 1-3 This invention provides a coagulation sedimentation tank for treating low-turbidity water, comprising a sedimentation tank 1, a baffle plate 2, an effluent weir 3, an inlet pipe 4, an outlet pipe 5, a sludge discharge pipe 6, a drive assembly 7, a turbulence turbulence assembly 8, a flow stabilization assembly 9, and a sludge discharge assembly 10.

[0027] Sedimentation tank 1 has a cylindrical upper part and a conical bottom. Sedimentation tank 1 is used to treat environmental wastewater such as domestic water and food wastewater. The cylindrical part of sedimentation tank 1 is the reaction zone, and the conical part is the sedimentation zone. The reaction zone is used for the mixing and reaction of reagents with water to enable flocculation reaction in the water. The sedimentation zone is used to settle residues, sludge and other impurities in the water.

[0028] The baffle plate 2 is fixedly connected to the top of the sedimentation tank 1. The upper part of the baffle plate 2 has a ring-shaped sawtooth structure. The sawtooth structure can evenly distribute the effluent, avoid excessively rapid or slow local water flow, ensure the stability of the effluent and the load balance of each area of ​​the sedimentation tank 1. By changing the direction of water flow, the sawtooth structure design can reduce turbulence and eddies, reduce disturbance to the settled sludge, and thus improve the sedimentation effect of the sedimentation tank 1. At the same time, the gaps in the sawtooth structure can effectively prevent floating debris such as foam and grease from entering the effluent weir 3.

[0029] Furthermore, with the same width of sedimentation tank 1, the serrated baffle plate 2 reduces the outflow per unit length by increasing the length of the water flow contact edge, making the outflow smoother and reducing the risk of short-circuiting. Existing straight weirs are prone to forming eddies that lead to sludge accumulation, while the serrated baffle plate 2 reduces the generation of eddies by dispersing the water flow direction, thereby reducing the probability of sludge deposition at the weir and reducing maintenance requirements.

[0030] Reference Figure 2 The effluent weir 3 is fixedly connected to the upper part of the outer side of the sedimentation tank 1. The overall shape is ring-shaped and it is used to ring the environmental wastewater that overflows from the top of the baffle plate 2 after sedimentation in the sedimentation tank 1. The outer side of the effluent weir 3 is fixedly connected to the effluent pipe 5, and the other end of the effluent pipe 5 is connected to the external environmental wastewater treatment network.

[0031] Reference Figure 1-3The inlet pipe 4 is fixedly connected to the lower part of the sedimentation tank 1. The low-turbidity environmental wastewater or domestic water to be treated enters the interior of the sedimentation tank 1 through the inlet pipe 4 via an external pump or gravity flow. It is located above the sedimentation zone. The end of the inlet pipe 4 away from the sedimentation tank 1 is connected to the environmental wastewater receiving network, and the outlet of the inlet pipe 4 faces the sedimentation zone inside the sedimentation tank 1.

[0032] The sludge discharge pipe 6 is located at the bottom center of the entire sedimentation tank 1 and is used to discharge sludge from the sedimentation zone inside the sedimentation tank 1.

[0033] Reference Figure 2 The drive assembly 7 includes a mounting frame 71, which is fixedly connected to the inner wall surface of the sedimentation tank 1 by support legs. The height of the mounting frame 71 is higher than the height of the sedimentation tank 1. A hydraulic cylinder 72 is fixedly connected to the top of the mounting frame 71. The output end of the hydraulic cylinder 72 passes through the mounting frame 71 and is connected to the central shaft 73. The central shaft 73 is vertically suspended along the central axis of the sedimentation tank 1. The central shaft 73 is a rigid rod and is constrained to only move up and down in the vertical direction of the central axis of the sedimentation tank 1, without rotating around the axis. The length of the central shaft 73 extends through the upper reaction zone of the sedimentation tank 1 and extends downward toward the sedimentation zone at the bottom of the sedimentation tank 1.

[0034] Reference Figure 3 In the upper reaction zone of the sedimentation tank 1, a turbulence-disrupting assembly 8 is provided. The turbulence-disrupting assembly 8 includes multiple layers of turbulence-disrupting plates 81 spaced apart along the central axis 73. The turbulence-disrupting plates 81 are fixedly connected to the central axis 73 and move vertically reciprocating synchronously with the central axis 73. Each turbulence-disrupting plate 81 has several turbulence-disrupting holes 82 on its surface, which are used to generate variable resistance disturbance to the water flowing through during the reciprocating motion, thereby promoting the collision flocculation of microparticles in the water under non-rotational shear conditions.

[0035] The baffle plate 81 is a horizontally arranged flat plate component, made of a corrosion-resistant material with a certain rigidity, such as stainless steel or reinforced engineering plastic. Each layer of baffle plate 81 is rigidly fixed to the outer wall of the central shaft 73 by key connection, flange connection, or welding, ensuring no relative movement between the baffle plate 81 and the central shaft 73. The outer diameter of the baffle plate 81 is slightly smaller than the inner wall diameter of the sedimentation tank 1, with a process clearance between them to avoid mechanical friction with the tank wall during movement.

[0036] Reference Figure 4 The spoiler 81 has a number of turbulence holes 82 that are formed through the surface of the plate. The geometric shape of the turbulence holes 82 is frustum-shaped, that is, the cross-sectional area of ​​the turbulence holes 82 along the thickness direction of the spoiler 81 is continuously changing. Specifically, each turbulence hole 82 has an upper opening on the upper surface of the spoiler 81 and a lower opening on the lower surface of the spoiler 81.

[0037] To achieve the diode effect in fluid dynamics, the diameter of the upper opening of the turbulence hole 82 is larger than that of the lower opening. The inner wall of the turbulence hole 82 smoothly transitions from the lower opening to the upper opening in a flared shape, forming a fluid channel with a constant cone angle. The cone angle is designed to be between 15 degrees and 45 degrees to ensure that the fluid can generate flow resistance differences and flow regime changes when flowing through the turbulence hole 82 in different flow directions.

[0038] When the baffle 81 moves downward with the central axis 73, the relatively flowing fluid enters through the lower opening and exits through the upper opening. The baffle holes 82 form a diffuser structure, used to induce boundary layer separation and form low-speed wake vortices. According to the principle of fluid continuity and Bernoulli's equation, as the fluid flows through the flared frustum-shaped channel, the velocity gradually decreases, and kinetic energy is converted into pressure energy, forming a diffused flow state. This diffusion effect causes boundary layer separation on the back surface above the baffle 81, inducing low-frequency, large-scale wake vortices. These vortices provide ample contact opportunities for fine particles and flocculants in the water, promoting the effective aggregation of fine particles into large flocs. The flow field shear force is low, making it difficult to break up the already formed flocs. Conversely, when the baffle 81 moves upward with the central axis 73, the relatively flowing fluid enters through the upper opening and exits through the lower opening. The baffle holes 82 form a converging nozzle structure, used to generate micro-jet with a certain penetrating power.

[0039] A number of turbulence holes 82 are evenly distributed or arranged in a concentric array on the surface of the turbulence plate 81. In a preferred embodiment, along the overall upward direction of the water flow, i.e., from the bottom turbulence plate 81 to the top turbulence plate 81, the opening ratio of each layer of turbulence plate 81, i.e., the ratio of the sum of the areas of all turbulence holes 82 in that layer to the total area of ​​the turbulence plate 81, is set in a gradient. The lower turbulence plate 81 has a smaller opening ratio to generate stronger turbulence intensity to promote the formation of micro-flocs, while the upper turbulence plate 81 has a larger opening ratio to reduce the fluid shear gradient, which is beneficial to the growth and protection of large flocs.

[0040] Furthermore, to further enhance the turbulence effect and prevent the formation of sedimentation dead zones in the baffles 81, the edges of the turbulence holes 82 are chamfered or rounded. Between two adjacent baffles 81, the corresponding upper and lower turbulence holes 82 are staggered in the vertical projection direction, forcing the fluid to be deflected when flowing between the baffles 81 layers, thereby increasing the residence time and collision probability of fluid particles in the reaction zone.

[0041] Reference Figure 5 The flow stabilizing component 9 is located below the reaction zone of the sedimentation tank 1. The flow stabilizing component 9 includes a multi-layer partition plate 91 fixed to the inner wall of the sedimentation tank 1. The flow stabilizing component 9 separates the upper reaction zone from the lower sedimentation zone in physical space, thereby reducing the transmission of pressure waves generated by the upper mechanical movement to the lower sedimentation zone.

[0042] The partition plate 91 is a horizontally arranged flat plate component, made of a corrosion-resistant material with a certain degree of rigidity and elasticity. Each partition plate 91 is fixedly connected to the inner wall of the sedimentation tank 1 and slidably connected to the central shaft 73.

[0043] In order to physically separate the upper reaction zone from the lower sedimentation zone and reduce the transmission of pressure waves generated by the mechanical movement of the upper baffle 81 to the lower sedimentation zone, a number of honeycomb holes 92 are formed through the surface of the partition plate 91, and the geometry of the honeycomb holes 92 is honeycomb-shaped.

[0044] When the baffle 81 moves downward with the central axis 73, the pressure wave generated is blocked by the multi-layered, elastic partition plates 91. The pressure wave causes the partition plates 91 to deform, thereby weakening the pressure wave and preventing the pressure wave generated by the mechanical movement of the upper baffle 81 from being transmitted to the lower sedimentation zone. This avoids the pressure wave disturbing the sludge in the bottom sedimentation zone. The honeycomb holes 92 are designed to allow the large flocs formed in the reaction zone to fall to the sedimentation zone at the bottom of the sedimentation tank 1 by their own gravity.

[0045] Reference Figure 6 and Figure 7 The sludge discharge assembly 10 includes a sludge discharge pipe 101, which is fixedly connected to the bottom center of the sedimentation tank 1, i.e., connected to the interior of the sedimentation zone. A check valve 102 is installed inside the sludge discharge pipe 101. A piston head 103 is fixedly connected to the bottom end of the sludge discharge pipe 101, located on the central axis 73. The piston head 103 has a cylindrical structure, and an elastic scraper sealing ring 104 is fixedly connected to the outside of the piston head 103. The piston head 103 is movably connected inside the sludge discharge pipe 101 and is located above the check valve 102.

[0046] The sludge discharge pipe 101 is fixedly installed at the center of the bottom of the sedimentation tank 1. The main body of the sludge discharge pipe 101 is a corrosion-resistant cylindrical metal component, or a steel pipe pre-embedded in the concrete at the bottom of the tank. The central axis of the sludge discharge pipe 101 coincides with the central axis of the sedimentation tank 1. The inner diameter of the sludge discharge pipe 101 is designed to be a constant value, which is larger than the outer diameter of the piston head 103 that it mates with, but smaller than the free outer diameter of the elastic sludge scraper sealing ring 104, to ensure that the elastic sludge scraper sealing ring 104 generates a predetermined amount of compression when inserted into the sludge discharge pipe 101.

[0047] Since the bottom of sedimentation tank 1 has a conical structure, the sludge discharge pipe 101 is fixedly located at the center of the bottom of sedimentation tank 1. That is, the bottom of sedimentation tank 1 is a truncated cone shape with a larger top and a smaller bottom, and its inner surface is a smoothly transitioning guide slope. When the piston head 103 swings as it descends with the central axis 73, the physical constraint of the guide slope forces the piston head 103 back to the central axis of the sludge discharge pipe 101, eliminating the centering error.

[0048] The sludge discharge pipe 101 is a straight-through structure, connected to the sludge discharge pipeline 6, which extends to a pipe gallery or operating well outside the sedimentation tank 1. A check valve 102 is installed inside the sludge discharge pipe 101, located in a non-submerged area for easy routine inspection and maintenance. The check valve 102 is directed away from the sedimentation tank 1, allowing fluid to be discharged outwards only through the sludge discharge pipe 101, while preventing the backflow of external fluid.

[0049] The check valve 102 is a back pressure sensitive valve, such as a swing check valve or a ball check valve. Its working logic is interlocked with the piston head 103 located in the sedimentation tank 1. When the piston head 103 moves upward in the sludge discharge pipe 101 and generates negative pressure, the check valve 102 is closed and sealed under the action of pressure difference to prevent external air or sludge from being sucked back. When the piston head 103 moves downward and squeezes, the pressure in the sludge discharge pipe 101 increases, the check valve 102 is opened, and the sludge is discharged through the sludge discharge pipe 101.

[0050] Reference Figure 8 In addition, the end face of the outlet end of the inlet pipe 4 located inside the sedimentation tank 1 is uniformly and fixedly connected with connecting rods 11. The ends of multiple connecting rods 11 away from the inlet pipe 4 are jointly and fixedly connected with a guide plate 12. The guide plate 12 is located on the central axis of the outlet end of the inlet pipe 4. The guide plate 12 has a conical structure, and a guide channel is formed between adjacent connecting rods 11 to guide the water flow to disperse into the sedimentation tank 1. The guide plate 12 is located above the sedimentation zone. Under the action of the conical structure of the guide plate 12 and the guide channel formed by multiple connecting rods 11, the inlet water that originally had horizontal impact momentum is dispersed and guided into a uniform upward flow. This can prevent the sewage from the inlet pipe 4 from directly impacting the sludge settled inside the sedimentation zone, thus ensuring the stability of the bottom sedimentation environment.

[0051] Working principle: During operation, the low-turbidity environmental wastewater or domestic water to be treated enters the sedimentation tank 1 through the inlet pipe 4 via an external pump or gravity flow. When the water flows out from the outlet end of the inlet pipe 4, it first impacts the guide plate 12 located on the central axis of the outlet end of the inlet pipe 4. Under the action of the conical structure of the guide plate 12 and the flow channel formed by multiple connecting rods 11, the inlet water, which originally had horizontal impact momentum, is dispersed and guided into a uniform upward flow, avoiding the direct scouring of the concentrated sludge layer at the bottom of the sedimentation tank 1 by the high-speed water flow, thus ensuring the stability of the bottom sedimentation environment.

[0052] Subsequently, the power drive assembly 7 begins to operate. The hydraulic cylinder 72 drives the central shaft 73 to perform periodic reciprocating motion in the vertical direction according to a preset frequency and stroke. This reciprocating motion includes two stages: a downward stroke and an upward stroke. The central shaft 73 drives the piston head 103 of the turbulence assembly 8 fixed on it and the mud discharge assembly 10 at the bottom to move synchronously.

[0053] During the downward stroke, hydraulic cylinder 72 pushes central shaft 73 downward. The various layers of baffles 81 located in the reaction zone move downward accordingly. Due to the inertia of the fluid, the water tends to flow upward relative to the baffles 81. At this time, water flows in through the lower opening of the baffle orifice 82 and out through the upper opening. According to the principle of fluid continuity and Bernoulli's equation, as the fluid flows through the flared frustum-shaped channel, the velocity gradually decreases, and kinetic energy is converted into pressure energy, forming a diffusion flow pattern. This diffusion effect causes boundary layer separation on the backflow surface above the baffles 81, inducing low-frequency, large-scale wake vortices. These vortices provide ample contact opportunities for fine particles in the water with the flocculant, promoting the effective aggregation of fine particles into large flocs, and the flow field shear force is low, making it difficult to break up the already formed flocs.

[0054] Meanwhile, at the bottom of sedimentation tank 1, the sludge discharge assembly 10 performs the sludge discharge action. The piston head 103 moves downward with the central shaft 73 and inserts into the interior of the sludge discharge pipe 101. If the piston head 103 has a slight sway in the initial downward movement, the conical guide ramp at the bottom of sedimentation tank 1 will force the piston head 103 to reset and center. As the piston head 103 moves downward, its outer elastic scraper sealing ring 104 forms a sliding seal with the inner wall of the sludge discharge pipe 101, compressing the internal volume of the sludge discharge pipe 101, causing the pressure inside the sludge discharge pipe 101 to rise rapidly. Under positive pressure, the fluid inside the sludge discharge pipe 101 opens the check valve 102, forcibly discharging the accumulated sludge through the sludge discharge pipe 101 and the extension of the sludge discharge pipeline 6 to the external treatment network. During this process, the flow stabilizing assembly 9 plays an isolation role, and the partition plate 91 uses its own elastic deformation to block and weaken the pressure wave generated by the downward movement of the turbulence plate 81, preventing it from being transmitted to the lower sedimentation zone and disturbing the sludge.

[0055] During the upward stroke, hydraulic cylinder 72 pulls the central shaft 73 upward. The baffle 81 located in the reaction zone moves upward accordingly, causing the water to flow downward relative to the baffle 81. At this time, water flows in through the upper opening of the baffle orifice 82 and out through the lower opening. The baffle orifice 82 forms a constricted nozzle structure, increasing the fluid velocity as it passes through the orifice throat, forming multiple downward micro-jet streams. These micro-jet streams cut and disturb the interlayer water, effectively eliminating short-flow dead zones and enhancing the micro-mixing efficiency of the reagent and water.

[0056] Simultaneously, the piston head 103 at the bottom moves upward within the sludge discharge pipe 101. As the piston head 103 rises, the volume of the chamber below the piston head 103 inside the sludge discharge pipe 101 increases, forming a momentary negative pressure zone. Under the pressure difference, the check valve 102 closes due to external back pressure and its own gravity, preventing the backflow of external fluid. At this time, the sludge in the sedimentation zone at the bottom of the sedimentation tank 1 fills the inlet area of ​​the sludge discharge pipe 101 under the combined action of gravity and negative pressure suction, preparing the volume reserve for the extrusion and discharge of sludge in the next downward stroke. The upward suction of the piston head 103 generates a downward suction flow field, which physically balances the upward drag force generated by the central shaft 73 on the surrounding fluid when it moves upward, helping to maintain the stability of the laminar flow state in the sedimentation zone.

[0057] After repeated flocculation reactions, the dense flocs formed in the water overcome the resistance of the rising water flow under the action of gravity, pass through the honeycomb holes 92 on the partition plate 91 of the flow stabilizing component 9, and settle to the conical sedimentation zone at the bottom of the sedimentation tank 1 for concentration, and are finally discharged by the sludge discharge component 10. The clarified water continues to rise and passes through the baffle plate 2. The serrated structure at the top of the baffle plate 2 evenly cuts and divides the supernatant, intercepts floating objects, and makes the effluent overflow evenly into the effluent weir 3, and finally collects into the effluent pipe 5 for discharge, completing the entire water treatment process.

Claims

1. A coagulation sedimentation tank for treating low-turbidity water, characterized in that, It includes a sedimentation tank (1), an inlet pipe (4), an outlet weir (3), and a drive assembly (7). The upper part of the sedimentation tank (1) is a reaction zone with a cylindrical structure, and the lower part is a sedimentation zone with a conical structure. The top of the sedimentation tank (1) is provided with a drive assembly (7), which includes a central shaft (73) suspended vertically along the central axis of the sedimentation tank (1). The central shaft (73) is constrained to move up and down only in the vertical direction. The central axis (73) located in the reaction zone is provided with a turbulence component (8), which includes multiple layers of turbulence plates (81) spaced apart along the axial direction. The turbulence plates (81) move vertically and reciprocally synchronously with the central axis (73) to generate disturbance to the water body. A sludge discharge assembly (10) is provided at the bottom center of the sedimentation tank (1). The sludge discharge assembly (10) includes a sludge discharge pipe (101) and a piston head (103) movably connected inside the sludge discharge pipe (101). The piston head (103) is fixedly connected to the bottom end of the central shaft (73) and moves vertically reciprocating synchronously with the central shaft (73). A check valve (102) is provided inside the sludge discharge pipe (101) and below the piston head (103).

2. The coagulation sedimentation tank for low-turbidity water treatment according to claim 1, characterized in that, The drive assembly (7) includes a mounting frame (71) and a hydraulic cylinder (72). The mounting frame (71) is fixedly connected to the inner wall surface of the sedimentation tank (1) and is higher than the sedimentation tank (1). The output end of the hydraulic cylinder (72) passes through the mounting frame (71) and is fixedly connected to the end of the central shaft (73) to drive the central shaft (73) to generate periodic reciprocating motion.

3. A coagulation sedimentation tank for low-turbidity water treatment according to claim 1, characterized in that, The spoiler (81) has a plurality of spoiler holes (82) through it. The spoiler holes (82) are frustum-shaped and have an upper opening on the upper surface of the spoiler (81) and a lower opening on the lower surface of the spoiler (81). The diameter of the upper opening is larger than that of the lower opening, and the inner wall of the turbulence hole (82) smoothly transitions from the lower opening to the upper opening in a widening shape, forming a fluid channel with a constant cone angle.

4. A coagulation sedimentation tank for low-turbidity water treatment according to claim 3, characterized in that, Along the central axis (73) from bottom to top, the opening ratio of each layer of the spoiler (81) is set in a gradient, wherein the opening ratio of the spoiler (81) located at the bottom is smaller than that of the spoiler (81) located at the top.

5. A coagulation sedimentation tank for treating low-turbidity water according to claim 1, characterized in that, The sedimentation tank (1) is provided with a flow stabilizing component (9) below the reaction zone. The flow stabilizing component (9) includes a multi-layer partition plate (91) fixedly connected to the inner wall of the sedimentation tank (1). The partition plate (91) is an elastic flat plate component with several honeycomb-shaped holes (92) through it. The partition plate (91) is slidably connected to the central shaft (73).

6. A coagulation sedimentation tank for low-turbidity water treatment according to claim 1, characterized in that, The piston head (103) has a cylindrical structure. An elastic mud-scraping sealing ring (104) is fixedly connected to the outer side of the piston head (103). The inner diameter of the mud discharge pipe (101) is larger than the outer diameter of the piston head (103) and smaller than the free outer diameter of the elastic mud-scraping sealing ring (104). The elastic mud-scraping sealing ring (104) forms a sliding sealing contact with the inner wall of the mud discharge pipe (101).

7. A coagulation sedimentation tank for low-turbidity water treatment according to claim 1, characterized in that, The sludge discharge pipe (101) has a straight-through structure and extends into the interior of the sedimentation tank (1). The check valve (102) is located in the non-water-submerged area outside the sedimentation tank (1) where the sludge discharge pipe (101) extends. The conduction direction of the check valve (102) is away from the sedimentation tank (1). The check valve (102) closes when the piston head (103) moves upward and generates negative pressure, and opens when the piston head (103) moves downward and generates positive pressure.

8. A coagulation sedimentation tank for low-turbidity water treatment according to claim 1, characterized in that, The inlet pipe (4) is fixedly connected to the lower part of the sedimentation tank (1) and located above the sedimentation zone. The end face of the outlet end of the inlet pipe (4) inside the sedimentation tank (1) is fixedly connected to a guide plate (12) by a connecting rod (11). The guide plate (12) is located on the central axis of the outlet end of the inlet pipe (4), and the guide plate (12) is a conical structure. A guide channel for guiding the dispersion of water flow is formed between adjacent connecting rods (11).

9. A coagulation sedimentation tank for low-turbidity water treatment according to claim 1, characterized in that, The top of the sedimentation tank (1) is fixedly connected to a slag baffle (2). The upper part of the slag baffle (2) is a ring-shaped sawtooth structure. The effluent weir (3) is fixedly connected to the upper part of the outer side of the sedimentation tank (1) to receive the water overflowing from the top of the slag baffle (2). The outer side of the effluent weir (3) is fixedly connected to an effluent pipe (5).

10. A coagulation sedimentation tank for low-turbidity water treatment according to claim 1, characterized in that, The inner surface of the conical structure at the bottom of the sedimentation tank (1) is smoothly connected to the end of the sludge discharge pipe (101) for physically guiding and resetting the piston head (103) when it moves downward.

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