Inclined shaftless screw classifier

Inclined shaftless screw classifier together with a tank for extraction of ash-sludge from a power plant. The ash-sludge have very fine particles. The particles enter the tank, go to the bottom and are extracted by the shaftless screw rotor. The shaftless screw rotor have a very low RPM value to avoid mixing of the particles into the water. The system takes out ash from process water in a simple and easy way. The systems avoids the process water to be treated in a special plant for handling this. This saves the power plant for expensive cost to handle poluted water.

What types of material are suitable for a screw classifier?

1. Materials that easy drop to the bottom of the water tank
2. Materals that do not dissolve in water
3. Materials that can be transported in a screw conveyor

See another example of a shaftless screw classifier

Why is a shaftless screw rotor effective to be used for a classifier?

• The water will very easy drain off, when the material comes up above the water level in the tank

When you work with a classifier, you must be able to control the speed of the screw rotor when it is put in operation. Therefor you always shall combine a frequency inverter together with the electrical motor. In this actual case the ash particles have a relatively low density. After installation the maintenance workes had to adjust:

• The speed of the shaftless screw rotor
• The time intervals between start and stop of the shaftless auger

After a few weeks, the screw classifier worked as planned. In this process the engineers and technicians of BEMA supported the client to obtain a problem free operation of the screw classifier.

FAQ: Inclined Shaftless Screw Conveyor Classifier

1. What is an inclined shaftless screw conveyor classifier used for?

This type of classifier is designed to separate solid particles from process water in an efficient and cost‑saving way. In the showcased installation, the system extracts fine ash‑sludge from a power plant’s process water. The particles settle at the bottom of the tank, where the shaftless screw rotor gently removes them without stirring them back into the water. This prevents the need for expensive external water‑treatment systems and simplifies plant operation.

2. Why is a shaftless screw rotor effective for classification?

A shaftless screw rotor allows water to drain easily once the material rises above the water level. Its open design prevents clogging and enables smooth handling of fine, wet, or sticky materials. Because classification requires precise control, the screw must run at low RPM to avoid mixing particles into the water. A frequency inverter is always recommended to adjust speed during commissioning and operation.

3. What types of materials are suitable for this classifier system?

The classifier is ideal for materials that settle quickly, do not dissolve in water, and can be transported by a screw conveyor. Typical examples include ash, sand‑like particles, and other mineral‑based solids. These materials naturally drop to the bottom of the tank, making extraction simple and reliable.

4. How is the system optimized during installation?

After installation, operators typically fine‑tune the screw speed and the start/stop intervals to match the material’s density and flow characteristics. In the referenced project, BEMA’s engineers supported the client throughout commissioning to ensure stable, trouble‑free operation.