A sludge agitator impeller for sewage treatment

Abstract

The application discloses a sludge agitator impeller for sewage treatment, which comprises a sludge agitator impeller body; a first arc is arranged at the water inlet end of the sludge agitator impeller body; the outer guide angle of the sludge agitator impeller body is arranged in a circular arc shape; and a second arc is arranged at the water outlet end of the sludge agitator impeller body. The sludge agitator impeller can improve the operation performance and operation efficiency of the agitator, meet the needs of the sewage treatment process, stabilize the water quality, improve the operation efficiency and provide strong support.

Description

Technical Field

[0001] This invention relates to sludge mixers in wastewater treatment technology, and more specifically, to an impeller for a sludge mixer used in wastewater treatment. Background Technology

[0002] Wastewater treatment plants have forced-propulsion agitators installed in the biological treatment tanks to forcibly agitate the sludge and prevent sludge sedimentation. Existing agitators mainly consist of a motor, impeller, and installation system to achieve the process requirements of solid-liquid two-phase flow and homogeneous flow of the solid and liquid phases during the biological treatment process. The impellers are precision-cast or stamped from materials such as stainless steel, and the blades are swept-back, resulting in high efficiency and anti-winding functionality.

[0003] Currently, most mixer designs focus on aspects such as axial thrust, number of blades, impeller diameter, and efficiency, resulting in largely standardized products.

[0004] Existing wastewater treatment plants all have fixed parameters at the factory, with fixed speed and frequency, and fixed motors.

[0005] Therefore, the conventional practice of installing sludge at the factory, while meeting the basic requirement of preventing sludge settling, lacks the limitation of proactively addressing the needs of wastewater treatment plant operations to maintain sludge flocs.

[0006] Existing agitators for sludge mixing have drawbacks such as over-mixing and the formation of cavitation cavities. These disadvantages are particularly pronounced in deep-type biological treatment tanks, where the double-layer agitator layout causes activated sludge flocs to break up, dispersing the treatment system, resulting in high energy consumption and undesirable activated sludge properties. Summary of the Invention

[0007] In view of the deficiencies in the existing technology, the purpose of this invention is to provide an impeller for a sludge mixer for wastewater treatment, which improves the operating performance and efficiency of the mixer, meets the needs of the wastewater treatment process, stabilizes water quality, improves operating efficiency, and provides strong support.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A sludge mixer impeller for wastewater treatment includes a sludge mixer impeller body.

[0010] The water inlet end of the impeller body of the sludge mixer is set in a first arc shape;

[0011] The outer guide angle of the impeller body of the sludge mixer is set to be arc-shaped;

[0012] The outlet end of the impeller body of the sludge mixer is configured as a second arc shape.

[0013] Preferably, the longitudinal section thickness of the water inlet is d1;

[0014] The length of the first arc is L1 = 5d1.

[0015] Preferably, the first arc is an elliptical arc;

[0016] The center distance of the elliptical arc is L1, and the radius is L1+d1.

[0017] Preferably, the diameter of the arc-shaped variable is 10d1.

[0018] Preferably, the longitudinal section thickness of the water outlet is d2;

[0019] The length of the second arc is L2 = 5d2.

[0020] Preferably, the second arc is an elliptical arc;

[0021] The distance between the centers of the elliptical arc is L2, and the radius is L2+d2.

[0022] Preferably, the longitudinal section thickness d1 of the water inlet is equal to the longitudinal section thickness d2 of the water outlet.

[0023] The length L1 of the first arc is equal to the length L2 of the second arc.

[0024] The sludge mixer impeller for wastewater treatment provided by this invention has the following beneficial effects:

[0025] 1) The biological treatment tank in wastewater treatment is the main energy-consuming process section. During daily operation, the agitator runs continuously, and the degree of sludge pulverization is uncontrollable. By improving the impeller in this invention, the agitator can effectively reduce the degree of sludge pulverization, achieve stable operation, and improve operating efficiency.

[0026] 2) The reduced impeller vacuum chamber improves hydraulic efficiency, achieving energy conservation and consumption reduction, with significant green benefits. Under the dual-carbon context, it not only enhances operational control capabilities but also improves the operational stability of the wastewater treatment plant.

[0027] 3) This invention solves the problem of in-situ optimization and improvement of the mixer, eliminating the need to purchase a new mixer, and can be widely adopted. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the sludge agitator impeller for wastewater treatment according to the present invention;

[0029] Figure 2 This is a schematic diagram of the longitudinal section of the impeller of the sludge mixer for wastewater treatment of the present invention at the water inlet end;

[0030] Figure 3This is a simulation diagram of the vacuum cavity of the impeller of the sludge mixer for wastewater treatment according to the present invention. Detailed Implementation

[0031] To better understand the above-mentioned technical solutions of the present invention, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0032] Combination Figure 1 As shown, in view of the characteristics of sludge in the biological reaction tank of a sewage treatment plant, the present invention provides a sludge agitator impeller for sewage treatment, including a sludge agitator impeller body 100, to meet the requirements of sludge-driven working scenarios.

[0033] The water inlet end 1 of the sludge mixer impeller body 100 is set in a first arc shape to reduce the impact surface and increase the contact surface, thereby reducing the degree of crushing of activated sludge flocs.

[0034] The outer guide angle 2 of the impeller body 100 of the sludge mixer is set to an arc shape and the curvature is improved to reduce fluid impact. By reducing the impact force, the generation of cavitation cavities is reduced, which plays a role in protecting the impeller.

[0035] The outlet end 3 of the sludge mixer impeller body 100 is set as a second arc shape to reduce the slope, thereby reducing the vacuum caused by fluid impact and improving the hydraulic efficiency of the impeller.

[0036] Combination Figure 2 The longitudinal section of the inlet end 1 of the sludge mixer impeller body 100 shown is illustrated. d1 represents the thickness of a single blade and is also the original blade end face shape, forming a 90-degree impact with the working fluid. Based on the hydraulic characteristics of the inlet end 1 of the sludge mixer impeller body 100, within a length range of 5 times d1 (i.e., length L1), the inlet end 1 is set as a first arc shape, which is set as an elliptical arc (e.g.,...). Figure 2 As shown by the dashed line, the larger side is located at the water inlet 1 (i.e., the original position of d1). The center distance of the elliptical arc is L1, and the radius is L1+d1.

[0037] The outer guide angle of existing impellers is generally obtuse. The working conditions in sewage treatment are different from those of ordinary agitators. The working fluid has higher viscosity and density. Therefore, under the working conditions of sewage treatment, the hydraulic model formed by this outer guide angle will form additional stress and cavitation, which will occur after long-term operation.

[0038] The outer guide angle 2 of the impeller body 100 of the sludge mixer is set as an arc. With the outer guide angle 2 as the center and a radius of 10 times that of d1, the center is mirrored and positioned. The outer guide angle 2 is then processed into an outer arc with a radius of 10 times that of d1.

[0039] The outlet end 3 of the sludge mixer impeller body 100 is configured similarly to the inlet end 1 of the sludge mixer impeller body 100, which can be referred to. Figure 2 As shown, based on the hydraulic characteristics of the outlet end 3 of the sludge mixer impeller body 100, within a length range of 5 times d2 (i.e., length L2), the outlet end 3 is set as a second arc, which is an elliptical arc, with the larger side located at the outlet end 3 (i.e., the original position of d2). The center distance of the elliptical arc is L2, and the radius is L2+d2.

[0040] In summary, the impeller of the sludge mixer for wastewater treatment in this invention is designed to meet the specific needs of the biological reaction tank in wastewater treatment plants. Compared with conventional submersible mixers, improvements have been made based on conventional submersible mixers. A method combining hydraulic model design and practical operational experience was employed, with particular optimization and improvement focused on three aspects: the pulverization characteristics of flocculation, cavitation characteristics, and sludge flow characteristics.

[0041] This invention alleviates the problem of high floc fragmentation in underground wastewater treatment plants: Existing wastewater treatment processes often result in highly fragmented activated sludge flocs in the biological reaction tanks, significantly impacting subsequent processes. This is primarily because floc fragmentation is directly related to the impact force at the impeller inlet. The original impeller's inlet face was at a 90-degree angle to the blades, resulting in a large impact force on the sludge. This caused the sludge flocs to be directly subjected to high-speed impact upon contact with this face, leading to their fragmentation. This invention modifies the impeller's hydraulic model, reducing the impact surface and increasing the contact surface at the inlet. By changing the impeller's inlet face to an arc shape, the impact force generated upon inlet is reduced, thus lowering the degree of activated sludge floc fragmentation. By controlling sludge quality at the source in the biological reaction tank, it becomes easier to adapt to the treatment requirements of subsequent processes, while also being practical and simplifying the process.

[0042] This invention alleviates cavitation in agitators: Existing impellers exhibit obvious cavitation marks on the chamfers near the water inlet, with almost every chamfer showing similar pitting depths. This is primarily due to the high density of sludge in the reaction tank, causing localized vacuum and resulting in cavitation pitting. Therefore, based on hydraulic model simulation results, this invention rounds the outer chamfer of the impeller and improves the curvature to reduce the vacuum caused by high-speed fluid flow. By reducing the vacuum cavity, cavitation pitting is minimized, thus protecting the impeller.

[0043] This invention improves the hydraulic efficiency of the impeller: Due to the high concentration and viscosity of sludge, its physical properties differ from those of conventional water. Therefore, the impeller design of general-purpose agitators is difficult to cover the special working conditions of sludge mixing. Based on the simulation results of the hydraulic model, combined with the location of the cavitation holes in the impeller and the simulated sludge flow state, the shape of the original impeller's outlet end easily generates a vacuum cavity (such as...) under high-speed operation. Figure 3(As shown). This invention employs a high-precision hydraulic model design to deeply optimize the hydraulic model of the sludge mixing impeller. By processing the outlet end of the impeller and creating a slope at the outlet end, the flow steps of sludge at the outlet end are alleviated, and the structural conditions for forming a vacuum cavity at the outlet end are reduced, thereby improving the hydraulic efficiency of the impeller.

[0044] Those skilled in the art should recognize that the above embodiments are merely illustrative of the present invention and are not intended to limit the present invention. Any variations or modifications to the above embodiments that are within the spirit and essence of the present invention will fall within the scope of the claims of the present invention.

Claims

1. An impeller for a sludge mixer used in wastewater treatment, characterized in that: Including the impeller body of the sludge mixer; The water inlet end of the impeller body of the sludge mixer is set in a first arc shape; The outer guide angle of the impeller body of the sludge mixer is set to be arc-shaped; The outlet end of the impeller body of the sludge mixer is configured as a second arc shape. The longitudinal section thickness of the water inlet is d1; The length of the first arc is L1 = 5d1; The longitudinal section thickness of the outlet end is d2; The length of the second arc is L2 = 5d2; The first arc is an elliptical arc; The distance between the centers of the elliptical arc is L1, and the radius is L1+d1; The second arc is an elliptical arc; The distance between the centers of the elliptical arc is L2, and the radius is L2+d2. The radius of the arc is 10d1.

2. The impeller of the sludge mixer for wastewater treatment according to claim 1, characterized in that: The longitudinal section thickness d1 of the water inlet is equal to the longitudinal section thickness d2 of the water outlet. The length L1 of the first arc is equal to the length L2 of the second arc.

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