air classifier principle of operation

Air classifiers for particle size analysis should produce extremely sharp cuts and they should allow the prediction of the actual cut size. In order to avoid systematic errors the construction should be appropriate to their function and to compete with other apparatus for particle size analysis the time required for one cut should be as short as possible. The principle and the requirements of counterflow equilibrium and transverse flow classification is discussed under these aspects and two new classifiers based on the conclusions drawn are described.

An overview is given of modern air classification devices, their operation principles, features and parameters, as cut size, cleanness and recovery. We outline the separation zones common to existing classifiers. In practice, various gravitational and centrifugal classifiers are employed, including those with vertical and horizontal air streams, cascade classifiers, fluidized bed separators, inertial, vortex, rotor classifiers, etc. Choice of the classifier type and designs is dictated by the technological requirements (throughput, cleanness, etc.) and the properties of materials to be classified. Advantages and limitations of the classifiers and basic trends in their development are considered.

Air classifiers for particle size analysis should produce extremely sharp cuts and they should allow the prediction of the actual cut size. In order to avoid systematic errors the construction should be appropriate to their function and to compete with other apparatus for particle size analysis the time required for one cut should be as short as possible. The principle and the requirements of counterflow equilibrium and transverse flow classification is discussed under these aspects and two new classifiers based on the conclusions drawn are described.