Thickener structure and principle

A thickener is a machine used to separate solid particles from a liquid slurry based on the principle of gravity sedimentation. The basic structure of a thickener consists of a cylindrical tank, a rake, a drive mechanism, and a feedwell.

The slurry is fed into the center of the tank through a feedwell, and it spreads out radially. The solid particles settle to the bottom of the tank under the influence of gravity and form a compact layer called the sludge bed. The clear liquid on top of the sludge bed overflows into a peripheral launder, which collects and removes the clarified liquid.

The rake mechanism, which is driven by a motor, slowly rotates around the tank, scraping the settled solids towards the center of the tank. The rakes move the settled solids to a discharge cone or hopper, which removes the thickened sludge from the bottom of the tank.

The principle of thickener operation is based on the settling velocity of the solid particles, which is determined by their size, shape, and density. The larger and denser particles settle faster and form a more compact sludge bed, while the smaller and lighter particles settle more slowly and form a less compact sludge bed. The design of the thickener and the operating conditions are optimized to achieve the desired separation efficiency and throughput.