Center-drive suction dredger (single-tube suction dredger)

• Product Overview

The central-driven single-tube sludge suction machine is a sludge discharge equipment manufactured by our company for circular radial-flow secondary sedimentation tanks. Its core function involves a central drive mechanism that rotates a suction pipe with multiple suction ports at the bottom. Under the combined effect of static water pressure and optional auxiliary suction, the machine evenly and steadily extracts the settled activated sludge from the tank bottom, thereby achieving solid-liquid separation.

The equipment is compact and stable, and is suitable for the small and medium-sized secondary sedimentation tank which requires the continuity, stability and sludge activity. It is one of the common supporting equipment in the sewage treatment process of activated sludge.

• Structure and Working Principle

1. Core structural composition

The entire system is centered around a vertical column and employs a vertical transmission mechanism.

• Drive unit: Located on the central operating platform of the sedimentation tank, it typically consists of a vertical motor, reducer, and torque overload protection device, providing the power for equipment rotation.
• Central transmission vertical shaft and rotating frame: The high-strength steel vertical shaft transmits power to the underwater system. The lower section of the shaft is connected to an "I" -shaped or "X" -shaped rotating frame, which secures the sludge suction pipeline.
• Single-pipe sludge suction system: The core working component of the equipment, consisting of a central sludge collection main pipe fixed under the rotating frame and multiple branch suction pipes uniformly distributed radially. The end of the branch pipes is equipped with adjustable suction ports, typically featuring duckbill-shaped or slit-type suction openings.
• The central rotary bearing and collector ring are located at the top of the central column, supporting the weight and overturning moment of the rotating components. A collector ring can be configured to power or transmit signals for auxiliary equipment.
• Sludge discharge trough and main pipeline: The upper end of the central sludge collection pipeline is connected to a fixed central sludge discharge trough, which discharges the collected sludge out of the tank through hydrostatic pressure or a connected sludge pump.
• Scum removal device (optional): A scum scraper may be attached to the rotating frame to collect surface scum and transfer it to the discharge hopper at the pool edge.

2. Working Principle

After the device is activated, the drive mechanism rotates the entire rotating frame and sludge suction pipe system at a low, uniform speed around the pool's central axis (typically 1-3 revolutions per hour) via the central vertical shaft.

1. Sludge collection: Activated sludge deposited at the bottom of the tank is drawn through evenly spaced suction ports at the branch pipes 'ends, converging into the central main collection pipe. The suction process is primarily driven by the static water pressure difference between the tank's liquid level and the sludge discharge pipe outlet, with minor siphon effect as an auxiliary. Some models are equipped with small submersible pumps to assist in the suction process.
2. Sludge discharge: The sludge collected in the central sludge collection pipe rises into the fixed central sludge discharge trough, and then is conveyed to the subsequent sludge treatment system by gravity or pumping through the sludge discharge main pipe connected to the sludge discharge trough.
3. Water separation: The supernatant after sludge removal is evenly discharged through the triangular weir around the tank.

• Core technical features

1. Compact structure and centralized layout: All driving and core transmission components are concentrated in the central area of the pool, resulting in a relatively simple overall structure with strong adaptability to civil engineering structures.
2. The sludge discharge is relatively balanced and the sludge layer is not disturbed: the sludge suction port is distributed uniformly along the radial direction, and the sludge in different areas of the bottom of the tank can be continuously and equally suctioned during the rotation, which helps to maintain the sludge interface in the tank relatively stable and reduce the disturbance to the settled sludge.
3. The operation is stable and the energy consumption is relatively low. The central transmission mode has stable operation track and mainly relies on hydrostatic pressure to discharge sludge. If the design is reasonable, the energy consumption can be maintained at a low level.
4. Maintenance and repair are relatively convenient: the main mechanical and electrical components are located on the operating platform at the center of the pool, making them easily accessible for daily inspections, lubrication, and maintenance.
5. Applicable to activated sludge: The gentle sludge suction method helps maintain the activity of the returned sludge, making it suitable for secondary sedimentation tanks requiring returned activated sludge.

• Main technical parameters

• Typical Application Fields

The central drive single-pipe sludge suction machine is primarily designed for the following applications:

• Municipal sewage treatment: The secondary sedimentation tank in the activated sludge process of urban sewage treatment plants is used for the balanced discharge and recirculation of activated sludge.
• Biochemical treatment of industrial wastewater: Utilizing secondary sedimentation tanks in industrial wastewater treatment plants (e.g., food, chemical, and pharmaceutical industries) that employ activated sludge processes.
• Other similar solid-liquid separation tanks: a circular sedimentation tank designed for stable and continuous discharge of lightweight sludge.