A volute sewage de-sludging machine

Abstract

The utility model relates to sewage treatment equipment technical field, and specifically is a kind of stacked screw sewage de-sludge machine. Stacked screw portion is driven screw shaft by main shaft motor, and screw shaft and the fixed ring, moving ring of alternate arrangement form 0.3~1mm filter gap and produce micro-motion self-cleaning, bottom is equipped with filtrate hole and water collecting tank, end is equipped with back pressure plate and sludge discharge plate, and upper is equipped with spray pipe;Stirring portion contains flocculation tank, stirring motor and dosing pipe, and sewage inlet and overflow port are matched, and are communicated with sludge inlet by conveying pump. Operation adopts 3~5rpm low speed, and combined pitch decrement and adjustable back pressure, realize along the way progressive pressurization;Sludge is concentrated by gravity first, then dewatered by deep extrusion, filtrate is discharged in time, and mud cake is smoothly unloaded. The device is low in energy consumption, not easy to block, low in water content, continuously and stably in operation, and is suitable for municipal and industrial sludge treatment.

Description

Technical Field

[0001] This utility model relates to the field of sewage treatment equipment technology, specifically a screw press sewage sludge desludge machine. Background Technology

[0002] Sludge dewatering for water treatment is a sludge treatment method that removes water from fluidized raw, concentrated, or digested sludge, transforming it into semi-solid or solid sludge blocks. The main dewatering methods include natural drying, mechanical dewatering, and granulation. Natural drying and mechanical dewatering are suitable for sewage sludge, while granulation is suitable for sludge produced by coagulation and sedimentation. An existing sludge dewatering machine for sewage treatment (publication number: CN223009930U) has the following disadvantages in use: Insufficient pressure at the beginning and a sudden increase at the end can easily lead to mud cake cracks and back mixing, resulting in low extrusion efficiency and difficulty in reducing moisture content. Forcibly increasing pressure by adding a plug at the end results in high operating resistance, high energy consumption, high impact torque, concentrated stress on bearings and reducers, and shortened lifespan. The material layer is eroded or leaks through gaps, leading to solid loss, increased suspended solids (SS) in the effluent, and large fluctuations in throughput and sludge output indicators.

[0003] The filter slots cannot loosen automatically, and the accumulation of surface deposits and pore blockage leads to a continuous decline in throughput, requiring frequent shutdowns for cleaning. High-pressure cleaning is necessary to restore throughput, resulting in large wash water volumes and secondary wastewater generation; filter cloth consumables require frequent replacement, and spare parts are expensive. Once local blockage occurs, uneven pressure on the filter bed leads to flow deviation, sludge leakage, and fluctuations in effluent quality, making long-term stable operation difficult.

[0004] The short residence time of sludge in the dewatering zone and insufficient pressing time result in high moisture content in the sludge cake, increasing transportation and disposal costs. High shear breaks up flocs, damages the filter bed structure, and reduces filtration rate and retention capacity. High-speed operation increases vibration and noise, leads to rapid wear of bearings, screws / drums, and other components, requires frequent maintenance, and results in significant downtime losses. Changes in sludge concentration / load cause instability, necessitating frequent manual intervention and parameter resetting.

[0005] The flocs have a loose structure and poor compressibility, exhibiting significant rebound after pressing, making it difficult to squeeze out water. The sludge cake easily adheres to equipment, increasing resistance and energy consumption. Without optimizing the dosing point, stirring intensity, residence time, and reagent molecular weight, insufficient dosage is ineffective, while excessive dosage increases costs and may even lead to an increase in effluent COD / SS. Furthermore, the lack of targeted conditioning for different sludge properties (municipal, dyeing, oily, fiber-containing, etc.) makes it difficult for the system to stabilize within its optimal operating range. Utility Model Content

[0006] The main purpose of this utility model is to provide a screw press type sewage desludge dewatering machine, which can effectively solve the problems in the background art.

[0007] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A screw press type sewage sludge dewatering machine includes a screw press section and a mixing section. The screw press section includes a main shaft motor, a screw shaft, a fixed ring, a moving ring, a filtrate hole, a back pressure plate, a sludge discharge plate, and a sludge inlet. The main shaft motor is connected to the screw shaft. A moving ring is fitted on the screw shaft. The inner diameter of the moving ring is smaller than the inner diameter of the screw shaft. When the screw shaft rotates, it drives the moving ring to rotate while the fixed ring remains stationary. The fixed ring and the moving ring are arranged alternately to form a filter gap of 0.3mm to 1mm. The back pressure plate is installed at the end of the screw shaft in the lateral direction of the screw movement. The screw press section is connected to the mixing section through the sludge inlet. The mixing section includes a flocculation box. The main shaft motor drives the screw shaft to run at a low speed of 3 to 5 revolutions per minute.

[0008] Furthermore, a filter hole is provided below the stacked screw section, and a water collection tank is installed thereon.

[0009] Furthermore, a mud discharge plate is provided below the back pressure plate, and there is a gap between the back pressure plate and the mud discharge plate to facilitate the extrusion of mud cake.

[0010] Furthermore, a spray pipe is provided above the spiral shaft of the stacked screw section.

[0011] Furthermore, a stirring motor is installed above the flocculation box and connected to a stirring shaft.

[0012] Furthermore, the flocculation box is also equipped with a dosing pipe, and a sewage inlet and a sewage overflow outlet are provided at the bottom of the flocculation box.

[0013] Furthermore, the mixing section is connected to the sludge inlet via a conveying pump, and the wastewater inlet is connected to the conveying pump to pump in sludge water.

[0014] Furthermore, a power distribution cabinet is installed on the side panel of the flocculation box.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The main shaft motor drives the screw shaft to rotate slowly, and the material moves forward with the screw. The screw pitch gradually decreases from the mud inlet to the end, and the back pressure plate provides adjustable resistance at the end. Together, they form a smoothly increasing pressing gradient along the process. A mud outlet plate with gaps is located below the back pressure plate, allowing the formed mud cake to be smoothly extruded without secondary blockage. The pressure is transmitted evenly, avoiding the "last-stage squeezing" that is loose at the beginning and tight at the end, reducing mud cake cracking and back mixing, and reducing mud loss and fluctuations in SS (suspended solids) in the output water. The torque impact is small, the drive is less labor-intensive, and the main shaft, bearings, and reducer are subjected to more stable stress and have a longer service life. Under the same mud output indicators, energy consumption is reduced and operation is more stable.

[0016] The alternating use of fixed and moving rings creates a filter gap of 0.3–1 mm. As the spiral shaft propels the material forward, the moving ring generates a slight relative motion in the circumferential direction, continuously scraping the filter gap boundaries. This, combined with the filtrate holes and water collection tank below the stacked screw section, ensures timely discharge of the filtrate. If necessary, a short-term spray from the upper spray pipe assists in restoring the flow rate. This "micro-motion self-cleaning" process significantly inhibits gradual clogging of the channels, maintaining long-term flow rate and filtration efficiency. It also reduces the frequency and volume of high-pressure water cleaning, lowering secondary wastewater and downtime maintenance costs. Filtration is more stable, resulting in smaller fluctuations in effluent quality and treatment capacity.

[0017] The main shaft motor operates at a low speed of approximately 3–5 revolutions per minute over a long process, creating a synergistic effect of "long dwell time and gradual pressurization" within the same shaft stroke. The low speed reduces shear damage to the flocs, while the long process ensures thorough pressing and permeation dewatering. The floc structure remains intact, and the filter layer maintains a "permeable and pressure-bearing" pore framework, resulting in more complete dewatering. The sludge cake forms stably, with a significantly reduced moisture content, leading to lower subsequent transportation and disposal costs. Noise, vibration, and wear are reduced, and maintenance frequency is decreased.

[0018] The mixing section is equipped with a flocculation tank, a mixing motor, and a mixing shaft. Flocculant is added at specific points via a dosing pipe. The wastewater inlet is coordinated with the wastewater overflow outlet to ensure a stable liquid level in the tank and more uniform retention and mixing. The large and dense flocs formed are then transported to the sludge inlet via a transfer pump. The pre-constructed, highly resistant floc particles, upon entering the screw press zone, are "pressed but not dispersed, squeezed but not stuck," significantly reducing adhesion between the back pressure plate and the moving / fixed ring surfaces, resulting in lower operating resistance. It adapts to fluctuations in sludge from different sources (municipal, dyeing, oily, fiber, etc.), maintaining a stable dewatering rate and effluent quality. The efficiency of chemical dosing is improved, avoiding the dilemma of "too little is ineffective, too much is burdensome." Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is the right view of the present invention; Figure 3 This is a schematic diagram of the stacked screw section structure of this utility model; Figure 4 This is a top view of the present invention; Figure 5 This is the right view of the present invention.

[0020] In the diagram: 1. Stacked screw section; 2. Stirring section; 11. Main shaft motor; 12. Screw shaft; 13. Fixed ring; 14. Moving ring; 15. Filtration hole; 16. Back pressure plate; 17. Sludge discharge plate; 18. Sludge inlet; 19. Spray pipe; 21. Flocculation box; 22. Stirring motor; 23. Dosing pipe; 24. Wastewater inlet; 25. Wastewater overflow outlet; 26. Power distribution cabinet. Detailed Implementation

[0021] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0022] In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0024] Example Please see Figure 1-5 This utility model provides a technical solution: A screw press type sewage sludge dewatering machine includes a screw press section 1 and a stirring section 2. The screw press section 1 includes a main shaft motor 11, a screw shaft 12, a fixed ring 13, a moving ring 14, a filtrate hole 15, a back pressure plate 16, a sludge discharge plate 17, and a sludge inlet 18. The main shaft motor 11 is connected to the screw shaft 12. The moving ring 14 is fitted on the screw shaft 12. The inner diameter of the moving ring 14 is smaller than the inner diameter of the screw shaft 12. When the screw shaft 12 rotates, it drives the moving ring 14 to rotate, while the fixed ring 13 remains stationary. The fixed ring 13 and the moving ring 14 are arranged alternately to form a filter gap of 0.3 mm to 1 mm. The back pressure plate 16 is installed at the end of the screw shaft 12 in the lateral direction of the screw movement. The screw press section 1 is connected to the stirring section 2 through the sludge inlet 18. The stirring section 2 includes a flocculation box 21. The main shaft motor 11 drives the screw shaft 12 to run at a low speed of 3 to 5 revolutions per minute.

[0025] Furthermore, a filter hole 15 is provided below the stacked screw section 1 and a water collection tank is installed thereon.

[0026] Furthermore, a mud discharge plate 17 is provided below the back pressure plate 16, and there is a gap between the back pressure plate 16 and the mud discharge plate 17 to facilitate the extrusion of mud cake.

[0027] Furthermore, a spray pipe 19 is provided above the spiral shaft 12 in the stacked screw section 1.

[0028] Furthermore, a stirring motor 22 is installed above the flocculation box 21 and connected to a stirring shaft.

[0029] Furthermore, the flocculation box 21 is also equipped with a dosing pipe 23, and a sewage inlet 24 and a sewage overflow outlet 25 are provided below the flocculation box 21.

[0030] Furthermore, the stirring section 2 is connected to the sludge inlet 18 via a conveying pump, and the sewage inlet 24 is connected to the conveying pump to pump in sludge water.

[0031] Furthermore, a power distribution cabinet 26 is installed on the side plate of the flocculation box 21.

[0032] The stacked screw section 1 is a filtration device composed of a series of fixed rings 13 and rotating rings 14 stacked alternately. A spiral shaft 12 runs through the center, driven by a main shaft motor 11 to rotate at a low speed of approximately 3-5 revolutions per minute. Multiple rotating rings 14 are mounted on the spiral shaft 12, their inner diameter slightly smaller than the outer diameter. When the spiral shaft 12 rotates, it drives the rotating rings 14 to rotate synchronously, while the fixed rings 13 remain stationary via the frame. This continuous relative movement between the rotating and fixed rings 14 creates filter gaps (approximately 0.3mm-1mm) and achieves a self-cleaning function, preventing clogging. The front section of the stacked screw section 1 is called the thickening section, and the rear section is called the dewatering section. The pitch of the spiral shaft 12 gradually decreases in both the thickening and dewatering sections, which, combined with the gradually narrowing filter gaps between the fixed and rotating rings 14, creates an increasingly increasing squeezing effect on the sludge. A back pressure plate 16 is installed at the end of the spiral shaft 12 in the forward direction, with a sludge discharge plate 17 below it. A certain gap is left between the back pressure plate 16 and the sludge discharge plate 17, which serves to apply back pressure to increase the pressing force of the sludge in the machine and facilitates the final extrusion and discharge of the sludge cake. The bottom of the screw press 1 is provided with a filtrate discharge outlet and a filtrate hole 15, and a water collection tank is installed to collect the separated filtrate. To facilitate cleaning and keep the filter gaps unobstructed, a spray pipe 19 is also arranged above the screw shaft 12, which can periodically spray and clean the filter ring assembly.

[0033] The mixing unit 2 mainly includes a flocculation tank 21 for flocculation reaction. A stirring motor 22 and its stirring shaft are installed on the top of the flocculation tank 21 to fully mix the sludge and flocculant entering the flocculation tank 21, causing fine particles to aggregate into larger flocs (lumps), improving subsequent dewatering efficiency. A dosing pipe 23 is provided on the flocculation tank 21, through which polymeric flocculants and other agents can be added to promote sludge flocculation. The bottom of the flocculation tank 21 is equipped with a wastewater inlet 24 and a wastewater overflow outlet 25: sludge enters the flocculation tank 21 through the wastewater inlet 24, and the wastewater overflow outlet 25 is used to maintain an appropriate liquid level and discharge excess liquid, preventing the flocculation tank 21 from becoming overfilled and affecting the flocculation effect. An electrical control cabinet 26 is also installed on one side panel of the flocculation tank 21, containing a control system that allows centralized control of the main shaft motor 11, stirring motor 22, dosing pump, and spray cleaning. The mixing section 2 is connected to the sludge inlet 18 of the screw press section 1 via pipelines and a delivery pump, forming a closed conveying channel: the delivery pump transports the pretreated flocculated sludge from the flocculation box 21 to the sludge inlet 18, and then into the screw press dewatering body. The entire device has a compact structure and reasonable design, which not only realizes the integration of flocculation and mechanical dewatering, but also facilitates automatic control and continuous operation.

[0034] During operation, this screw press sludge dewatering machine transforms water-containing sludge into low-moisture cakes through two stages: flocculation pretreatment and mechanical extrusion dewatering, thereby filtering out clean water. Its specific workflow and principle are as follows: The sludge to be treated is first pumped to the wastewater inlet 24 of the flocculation tank 21 by a sludge transfer pump. Before entering the flocculation tank 21, the sludge is usually regulated by a metering tank or flow meter to ensure a stable feeding rate, which facilitates effective control of subsequent chemical dosing and mixing processes.

[0035] After the sludge enters the flocculation tank 21, the stirring motor 22 is turned on to drive the stirring shaft to rotate, thoroughly agitating the sludge. An appropriate amount of flocculant (such as an organic polymeric flocculant) is added through the dosing pipe 23. Under agitation, the fine solid particles in the sludge quickly aggregate into larger flocs (commonly known as "flocs"). The formation of flocs helps improve solid-liquid separation efficiency—the larger and denser the particles, the easier they are to be retained and filtered in subsequent processes. During the agitation process, the wastewater overflow port 25 inside the flocculation tank 21 maintains a constant liquid level, discharging excess clarified liquid to ensure the sludge has sufficient residence time in the tank to complete the reaction and prevent overflow.

[0036] The fully flocculated sludge is pumped from the bottom of the flocculation tank 21 to the sludge inlet 18 of the screw press section 1, entering the screw press dewatering body. First, the sludge enters the front thickening section of the screw press body. Driven by the main shaft motor 11, the screw shaft 12 slowly pushes the sludge forward at a low speed of 3-5 revolutions per minute. In the thickening section, due to gravity and the initial squeezing action of the filter ring structure, a large amount of free water in the sludge is separated: as the sludge moves slowly forward, the liquid flows out through the annular gap between the fixed ring 13 and the moving ring 14 under the influence of gravity, exiting from the filtrate hole 15 at the bottom of the screw press section 1 and collecting in the water collection tank. This stage is equivalent to pre-thickening the sludge, significantly reducing its volume. It is worth noting that the moving ring 14, driven by the screw shaft 12, continuously rotates and slides relative to the fixed ring 13, acting like a filter screen scraper, continuously cleaning the filter gaps to prevent sludge from clogging them. The screw press structure eliminates the need for traditional filter cloths, avoiding the filter clogging and downtime cleaning issues common in other dewatering equipment. Therefore, even when processing easily clogged materials such as oily sludge during the concentration stage, this device can maintain unobstructed filter gaps and stably and continuously complete gravity dewatering.

[0037] The sludge, after being concentrated and pre-dewatered, continues to be pushed into the rear dewatering section by the screw shaft 12. In the dewatering section, the pitch of the screw shaft 12 decreases further compared to the concentration section, while the annular gap between the fixed ring 13 and the moving ring 14 also gradually decreases, from approximately 1 mm initially to approximately 0.3 mm or even narrower. The gradual contraction of the screw cavity continuously increases the compressive force on the sludge, equivalent to applying progressively increasing mechanical compression to the sludge. In addition, the back pressure plate 16 installed at the outlet of the dewatering section provides additional resistance (back pressure), further increasing the pressure within the cavity. As the sludge is pushed closer to the outlet, due to the limited space and back pressure, the sludge is compressed to a higher degree of dryness, and the internal water is squeezed out as much as possible, exiting the machine through the annular gap and filtrate holes 15. This process achieves deep dewatering of the sludge: the sludge is transformed from a soft, flocculent material into a semi-dry sludge mass with a high solids content. It should be noted that while the spiral shaft 12 propels the sludge, it also drives the self-cleaning filter gaps of the moving ring 14, ensuring that the filtration channel remains unobstructed and does not become clogged under high pressure. The back pressure plate 16 can also be adjusted in position or pressure as needed to control the moisture content of the sludge cake and the sludge discharge rate, adapting to different sludge characteristics and treatment requirements.

[0038] After the sludge has been fully pressed and dewatered, the resulting drier sludge cake is pushed against the back pressure plate 16 and squeezed out of the machine body through the gap at its lower edge, sliding onto the discharge plate 17 and being discharged from the equipment. Due to the reasonable design of the gap between the back pressure plate 16 and the discharge plate 17, excessively thin sludge is prevented from flowing out directly, while ensuring that the sludge cake can be discharged smoothly and continuously without sticking or clogging. While the sludge cake is being discharged from the machine, the back pressure plate 16's blocking effect maintains a certain pressure within the dewatering section, thus ensuring a continuous and stable dewatering effect. The discharged sludge cake has a significantly reduced moisture content, facilitating subsequent processing or transportation. The filtered water is collected in a collection tank and then discharged or reused. This completes one work cycle, and the equipment can then proceed to the next batch of feed and dewatering. Throughout the dewatering process, the control system coordinates the operation of the main shaft motor 11, the stirring motor 22, and the conveying pump through the electrical control cabinet 26, achieving continuous automatic operation of feeding, flocculation, dewatering, and sludge discharge. If too much solids adhere to the filter ring after long-term operation, the operator can also turn on the spray pipe 19 to rinse the filter gaps and spiral, further ensuring the long-term stability and dewatering efficiency of the equipment.

[0039] The foregoing description and illustrations of this utility model illustrate its basic principles, main features, and advantages. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A screw press type sewage sludge dewatering machine, comprising a screw press section (1) and a stirring section (2), characterized in that: The stacked screw section (1) includes a main shaft motor (11), a screw shaft (12), a fixed ring (13), a moving ring (14), a filtrate hole (15), a back pressure plate (16), a mud discharge plate (17), and a mud inlet (18). The main shaft motor (11) is connected to the screw shaft (12). The moving ring (14) is fitted on the screw shaft (12). The inner diameter of the moving ring (14) is smaller than the inner diameter of the screw shaft (12). When the screw shaft (12) rotates, it drives the moving ring (14) to rotate. The fixed ring (13) is fixed in place. The fixed ring (13) and the moving ring (14) are arranged alternately to form a filter gap of 0.3mm to 1mm. The back pressure plate (16) is installed at the end of the spiral shaft (12) in the transverse direction of the spiral movement. The stacked screw section (1) is connected to the stirring section (2) through the mud inlet (18). The stirring section (2) includes a flocculation box (21). The main shaft motor (11) drives the spiral shaft (12) to run at a low speed of 3 to 5 revolutions per minute.

2. The screw press type sewage sludge dewatering machine according to claim 1, characterized in that: The stacked screw section (1) has a filter hole (15) below it and a water collection tank is installed thereon.

3. The screw press type sewage sludge dewatering machine according to claim 1, characterized in that: A mud discharge plate (17) is provided below the back pressure plate (16), and there is a gap between the back pressure plate (16) and the mud discharge plate (17) to facilitate the extrusion of mud cake.

4. The screw press type sewage sludge dewatering machine according to claim 1, characterized in that: The stacked screw section (1) is provided with a spray pipe (19) above the spiral shaft (12).

5. The screw press type sewage sludge dewatering machine according to claim 1, characterized in that: The flocculation box (21) is equipped with a stirring motor (22) and a stirring shaft.

6. The screw press type sewage desludge dewatering machine according to claim 1, characterized in that: The flocculation box (21) is also equipped with a dosing pipe (23), and a sewage inlet (24) and a sewage overflow outlet (25) are provided below the flocculation box (21).

7. A screw press-type sewage desludge dewatering machine according to claim 1, characterized in that: The mixing unit (2) is connected to the mud inlet (18) via a delivery pump.

8. A screw press-type sewage desludge dewatering machine according to claim 1, characterized in that: The flocculation box (21) is equipped with a power distribution cabinet (26) on its side panel.

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