Many industrial processes require particles to be separated into different classes according to particle size. This process is known as classification and is most often accomplished by the use of sieves or screens where a series of sieves or screens with different aperture sizes separate the product into size classes. Where the particles are very fine sieves cease to be effective and an air classifier is used. The product stream is fluidity in an upward moving column of air whose velocity is reduced as the air rises. Since larger particles have a higher settling velocity than finer particles the air classifier can be used to draw off air streams entraining particles of differing specific sizes with the finer particles passing further up the classifier vessel. The particles must then be efficiently separated from the entraining air stream. Depending on flow rates AAF product like FabriPulse L, or OptiFlo RC are ideal.