Evaluation of fine particle removal capability of multi inner stage cyclone

A three-layer-type multi inner stage (MIS) cyclone capable of removing fine particles generated by electronic industrial processes was successfully developed with a high processing rate, minimal maintenance and repair cost, and low energy loss. To investigate the capability of the MIS cyclone, experiments were performed using Al₂O₃ particles with diameters of 1, 3, 5, 10, 15 and 20 μm under particle inlet velocities of 0.85, 2.55, 4.25, 5.94 and 8.49 m/s. Lapple (1950), Barth (1956), and Iozia and Leith (1989) prepared a cyclone efficiency prediction graph using a collection efficiency prediction model under the same operating conditions as the MIS cyclone. They verified the cyclone efficiency by comparing the efficiency prediction graph and the general cyclone experimental data with the MIS cyclone experimental data. For an Al₂O₃ fine particle diameter smaller than 5μm, the particle removal capability of the MIS cyclone was observed to be significantly higher than that of the predicted efficiency of a general cyclone and its actual experimental efficiency. Furthermore, the variation of collection efficiency with particle size was not as significant as that of a general cyclone, which suggested the MIS cyclone possesses a more stable removal capability. Pressure drop measurement results of the MIS cyclone showed that a maximum pressure drop of 11 mmAq occurred under an inlet velocity of 8.49 m/s, which was considerably lower than that of a general cyclone pressure drop (50∼150 mmAq).