Sand classifiers

A sand classifier is used in material processing to classify and separate sand or other bulk materials according to their grain size.

Upflow classifiers: In this method, the material is moved from bottom to top in a stream of water. The flow carries lighter material (e.g. finer sand or sludge) upwards, while heavier grains (e.g. coarser sand) sink and settle at the bottom. This technique is particularly useful for separating finer and heavier particles.

Free-fall classifier: The sand/water mixture flows longitudinally through a trapezoidal water tank. The tank is equipped with several outlet nozzles at the bottom. The slow flow causes the sand grains to sediment. These settle continuously on the bottom in proportion to their grain size.

The outlet nozzles are opened and closed via a PLC control system, which enables the controlled discharge of the various sand fractions. The discharged products are collected in a collection channel and mixed to form a predefined sand fraction. The collection channel usually feeds the product to a sand dewatering screen, where excess water is separated.