Center Drive Sludge Scraper and Suction Machine
In circular / radial-flow sedimentation tanks, the tank bottom is sloped and sludge converges toward the center. If the sludge discharge device is not properly matched, problems such as "sludge accumulation around the periphery and incomplete discharge at the center" may occur, and sludge may even float due to anaerobic conditions. The center drive sludge scraper and suction machine uses center-of-tank drive and rotating scraper arms to continuously scrape and collect bottom sludge toward the central sludge collection pit for discharge, with simultaneous scum skimming and flow stabilization. It is the standard sludge discharge equipment for circular sedimentation tanks (including sludge thickening tanks) in water supply plants and wastewater treatment plants.
I. Product Positioning
The center drive sludge scraper and suction machine is specialized bottom sludge discharge equipment for circular / radial-flow sedimentation tanks. It consists of a center-of-tank drive unit (motor + reducer + slewing bearing), working bridge (truss or platform), scraper arms and scraper blades, scum skimming and flow stabilization devices, and electrical control system; the drive unit is located at the center of the tank and drives the scraper arms to rotate slowly around the tank center. The scraper blades scrape and collect bottom sludge along the slope toward the central sludge collection pit, and then it is discharged out of the tank through the central sludge discharge pipe. It is widely used in radial-flow sedimentation tanks in water supply plants, primary clarifiers, secondary clarifiers in wastewater treatment plants, and sludge thickening tanks (center drive thickeners).
II. Working Principle (Brief)
Center drive: The center-of-tank drive unit (motor + reducer + slewing bearing) drives the working bridge and scraper arms to rotate uniformly around the tank center.
Rotary sludge scraping: The scraper blades on the scraper arms (often arranged along a logarithmic spiral) slowly scrape bottom sludge along the slope toward the central sludge collection pit.
Central sludge discharge: Sludge collected in the central sludge collection pit is discharged continuously or intermittently out of the tank through the central sludge discharge pipe / valve.
Scum skimming (optional): The scum scraping plate at the front end of the scraper arm scrapes floating scum on the water surface to the central or peripheral scum discharge hopper, completing surface cleaning.
Flow stabilization (optional): The inlet flow stabilization cylinder weakens inlet disturbance and ensures stable hydraulic sedimentation conditions in the tank.
Continuous rotary operation: Low-speed rotation in continuous or intermittent mode, with automatic start-stop control and linkage with sludge level, requiring minimal attendance.
Process schematic: center drive → scraper arms rotate to scrape and collect bottom sludge → converge to central sludge collection pit → discharge through central sludge discharge pipe ⇄ (optional) scum skimming / flow stabilization → full-tank rotation without dead zones
The core lies in "scraping toward the center, discharging upon rotation"—slowly rotating around the tank center as the axis, continuously pushing accumulated sludge on the entire circular tank bottom slope toward the center, ensuring uniform sludge discharge while avoiding anaerobic floating of dead sludge around the periphery, with stable operation and low energy consumption.
III. Core Advantages
① Dedicated for circular tanksSpecially designed for radial-flow / circular sedimentation tanks, matching the tank bottom slope for close sludge discharge.
② Compact center drive structureThe drive is concentrated at the tank center, with reasonable force distribution and stable transmission, requiring no long track along the tank perimeter.
③ Stable rotation and low energy consumptionSlow rotation and low power, economical operation, suitable for long-term continuous operation.
④ No dead zones in the entire tankLogarithmic spiral scraper blades cover the entire tank bottom slope, thoroughly collecting sludge toward the center.
⑤ Integrated scum skimming and flow stabilizationOptional scum scraping and flow stabilization cylinder, combining sludge scraping, scum skimming, and flow stabilization in one machine.
⑥ Easy maintenanceCenter drive components are concentrated with few underwater bearings, convenient for inspection and repair, with universal spare parts.
IV. Main Technical Parameters (Reference Range)
Item | Parameter Range / Description | Remarks |
|---|---|---|
Applicable tank type | Circular / radial-flow sedimentation tank | Not rectangular tanks |
Tank diameter | Usually 6–20 m (larger diameters should use peripheral drive) | Center drive suitable for small to medium diameters |
Peripheral linear speed / scraper arm rotation speed | Approx. 1–3 m/min (slow rotation) | Adjusted according to diameter |
Drive mode | Center drive (motor + reducer + slewing bearing) | Drive located at tank center |
Scraper blade type | Inclined scraper blade / logarithmic spiral scraper blade | Fits tank bottom slope |
Auxiliary devices | Scum skimming, flow stabilization cylinder (optional) | Configured as needed |
Main material | Anti-corrosion carbon steel / stainless steel | Selected according to water quality and service life |
Control mode | Local / remote, continuous / intermittent | Can be integrated into automatic control system |
Motor power | Determined by diameter and load | Low speed and low consumption |
* The above are typical reference ranges. Actual tank diameter, rotation speed, and drive mode shall be based on tank design and process requirements.
V. Typical Application Scenarios
Scenario / Industry | Adaptation Description / Main Function |
|---|---|
Radial-flow sedimentation tank in water supply plant | Continuous bottom sludge discharge in circular sedimentation tank, ensuring stable effluent. |
Primary clarifier in wastewater treatment plant | Removes settled sludge, reducing subsequent biochemical load. |
Secondary clarifier in wastewater treatment plant | Discharges excess / return sludge, maintaining activated sludge system balance. |
Sludge thickening tank | As a center drive thickener, scrapes and collects thickened sludge. |
Circular sedimentation tank for industrial wastewater | Sludge discharge for various industrial wastewater circular sedimentation facilities. |
Circular sedimentation for reclaimed water reuse | Mechanical sludge discharge for circular sedimentation section in reuse processes. |
Circular variant of high-efficiency sedimentation tank | Supporting sludge discharge equipment for circular high-efficiency clarification units. |
VI. Selection Recommendations
The center drive sludge scraper and suction machine is only suitable for circular / radial-flow sedimentation tanks; rectangular tanks should use traveling bridge sludge scraper and suction machines. Generally, small to medium diameters (approx. ≤20 m) use center drive, while larger diameters should use peripheral drive to balance drive loads. During selection, the tank bottom slope and central sludge collection pit design must be reasonable to ensure smooth sludge convergence toward the center; underwater bearings and slewing bearings should be well protected against corrosion; in severe cold regions, attention should be paid to freeze protection and outdoor electrical protection; if there is a lot of scum on the tank surface, it is recommended to equip scum skimming devices simultaneously.
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FAQ
How much does this equipment cost?
The price varies by treatment capacity, water quality, materials and configuration, so a custom quote is provided based on your actual conditions. We offer free water testing and solution design, with a detailed quote within 1 working day after requirements are confirmed.
What treatment capacity is available? Can it be customized?
Capacity is fully customizable, ranging from tens to thousands of tons per day (e.g. 0.5–30 m³/h), with non-standard design support matched precisely to your inlet/outlet requirements.
How long does delivery take?
Standard equipment typically takes about 2–4 weeks to produce; custom projects depend on scale and process. The delivery date is confirmed at contract signing, with design, manufacturing and shipping progressing on schedule.
Is installation and commissioning included?
Yes. We provide installation, system commissioning, operator training and environmental acceptance assistance, as well as long-term managed operation services on request.
What about after-sales and warranty?
We provide a warranty period and a 24/7 technical hotline, with free repair for non-human faults during the warranty period, plus spare parts supply and regular inspection services.
Let circular tank bottom sludge "return to the center"
We can provide selection and complete supply solutions for center drive sludge scraper and suction machines based on circular tank diameter, sludge characteristics, and automatic control requirements. Welcome to call or leave a message.
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Traveling Bridge Scraper and Suction Sludge Collector
Horizontal-flow, rectangular large-span sedimentation tanks have wide bottoms and accumulate a large amount of sludge. Manual sludge removal is time-consuming and labor-intensive, and uneven sludge discharge can easily form "dead sludge" that decays and floats up. The traveling bridge scraper and suction sludge collector uses a bridge truss spanning the tank to travel back and forth, scraping and collecting sludge from the tank bottom and suctioning it out of the tank, with simultaneous scum skimming. It enables mechanized and automated sludge discharge from sedimentation tanks and is standard equipment for horizontal-flow sedimentation tanks in water treatment plants and wastewater treatment plants.
Peripheral Drive Scraper and Suction Sludge Collector
For large circular / radial-flow sedimentation tanks with diameters of tens of meters, center drive results in excessive rotational load, long scraping distance, and uneven sludge discharge, making it easy for sludge to accumulate at the far end. The peripheral drive scraper and suction sludge collector moves the drive unit to the tank-side track, where the peripheral traveling wheels drive the entire bridge to rotate around the center. The load is distributed, making it suitable for large spans. It steadily scrapes sludge from the bottom of the entire large-diameter tank toward the center for discharge, making it the main sludge removal equipment for circular tanks in large water supply plants and wastewater treatment plants.