COLLECTION CHARACTERISTICS OF THE SPECIAL FORMS OF THE RETURNED FLOW TYPES OF THE CYCLONE DUST COLLECTORS

Up to this time there have been many papers concerning theoretical and experimental investigations of the collection efficiencies of the axial flow types and of the returned flow types of cyclone dust collectors. However it is very difficult to estimate the collection efficiencies by a numerical analysis, since an exact grasp of the three dimensional turbulent rotational flow and of the behaviours of the fine solid particles on the centrifugal field in the cyclone dust collector can not be obtained. Therefore the authors made two kinds of normal (standard) cyclone dust collectors and five kinds of special forms (cone cyclones, sphere cyclones and a semi sphere and cone combined cyclone) of the returned flow types of the cyclone dust collectors. Then in order to compare the collection efficiencies of the normal cyclone dust collectors with those of the special forms of the cyclones, fine fly-ash particles were used as a test dust. In this paper the characteristics of the collection efficiencies of the above mentioned seven cyclone dust collectors which were related to the centrifugal effect, the feed dust concentration and the feed dust mass per unit time per energy dissipation of air flow are described in detail.