ABSTRACT
This chapter deals with particle separation principles and devices. The separating efficiency of a dust collector is the principal characteristic in comparing competing devices and considering its applicability to a particular air/gas stream. It is common practice to consider separation efficiencies above 90 percent as inherently good but this is obviously a fallacious basis for judging adequacy of a dust collector installation. Mists are liquid droplets which behave in air cleaning devices like fumes or dust, depending on their particle size, i.e., inertia. Dusts and fumes are dislodged by a vibratory rapping on the collected electrodes. Fine dust includes higher proportions of small particles of a size characteristic of fumes, requiring collection devices of superior efficiency. The collision of dust or mist particles with droplets of water in various types of scrubbers or with fibers in some types of dust filters due to relative velocity of the two is one of the important mechanisms of dust collection.
