Operation and Control Management of Horizontal Decanter Centrifuge in Wastewater Treatment Plant

Non-adjustable mechanical factors of horizontal decanter centrifuge

Drum diameter and effective length

The larger the volume of sedimentation treated by effective conveying, the stronger the precipitation handling capacity will be. Also, the longer the retention time of material molecules in the drum chamber of the industrial centrifuge, the greater the separation resistance coefficient, and the better the efficiency of centrifugation under the same speed. However, due to the influence of the size of material shape, the maximum turning radius of the centrifuge drum plate will not increase without limit, because the maximum allowable speed has been reduced due to the increase in diameter and the decrease in centrifugal force.


The drum can be divided into deep liquid pools and shallow liquid pools according to its shape. The deep liquid pool is used to process sludge and pasty materials. The principle is that the high torque generated by the screw compresses the settled material to dehydrate the sludge. The shallow liquid pool is used to process rough and internally gapped particles of sediment, so that water can pass through the particle gaps and discharge to the solid phase for dehumidification.

Design of screw

The pitch of the screw refers to the relative horizontal distance between two rotating screw blades of the machine and two adjacent spiral blade diameters of adjacent machines. It is often an important process structure parameter in the entire equipment, and it determines the speed of screw conveying. The easier the settling substance is to be conveyed, the larger the pitch can be. The pitch will directly affect the outcome of the sludge conveying work.

When the diameter of both rotating wing screws of the machine reaches a certain height, the larger the pitch value, the larger the helix angle value, and the greater the conveying opportunity of the sludge is blocked between adjacent spiral blade diameters. At the same time, increasing the pitch will reduce the number of rotations of the screw blade diameter, making it difficult for the sludge to reach a uniform state of distribution between the cone end blades of the screw drum. This will cause the internal vibration and pressure of the entire screw machine to increase.

In order to facilitate the effective transportation and separation of sludge, the pitch angle should not be too large. The best range for industrial centrifuges is about 6 degrees or less to reduce the sludge's transport backflow or separation speed.

Material of equipment

Parts that come into contact with materials and their volatile vapors must be made of materials that are resistant to chemical and physical corrosion. In special projects, high-nickel-based alloy materials may be used if required on site. Attention should be paid to factors such as the chemical concentration of the material and the operating temperature during operation.

Adjustable mechanical factors of horizontal decanter centrifuge

Drum speed

The adjustment method of the drum speed, which determines the high or low speed of the drum, is currently usually achieved by multi-motor three-phase AC variable frequency motors, direct adjustment, or by driving the rotation direction of the hydraulic motor. The higher the speed requirement, the stronger the centrifugal force, which is beneficial to quickly increase the soluble solid content on the surface of the cement cake.

However, the usually high requirements for drum speed can often cause moisture damage and sludge cohesion, reducing the final dewatering and purification of sludge. At the same time, the relatively high-speed requirements for the entire material conveying device use three-phase motors, which cause large wear areas in the entire three-phase machine system, large changes in power parameters, large power consumption losses, and large vibration noise losses. All these factors increase the wear and tear on the system.

Differential speed ratio

The speed difference directly affects the strength of sludge discharge, the cake degree of mud, and the quality of screened liquid, and is one of the key technical parameters that must be adjusted according to the working conditions of the horizontal screw industrial centrifuge machine. Although increasing the differential speed can increase the sludge discharge capacity, it will also reduce the dehydration time of sediment, resulting in high moisture content of the dehydrated mud cake.

There is a certain contradiction between improving the capacity of sludge treatment and improving the effect of sludge treatment. In order to effectively improve the treatment capacity of sludge, it is necessary to further increase the difference between mud and speed, and appropriately reduce the dryness of mud. Therefore, on-site simulation adjustment work should be carried out to find the best differential speed range according to the material properties, processing capacity, processing requirements, and the structural parameters of the centrifuge in industry, in order to achieve the highest processing capacity under conditions that meet the mud dryness.

Get Optimal Separation
Support From SAIDELI.