Cyclone vibration effects

Abstract

A Governmental Accounting Office review of coal mine dust sampling procedures recommended studies be performed to determine accuracy and precision of dust measurements taken with current equipment. The effects of vibration on the 10-mm Dorr-Oliver nylon cyclone run at a flow rate of 2 L/min were investigated. A total of 271 samples were taken during 95 tests. All tests lasted about 7 h each and were performed inside a 19-L capacity aerosol chamber. Coal dust concentrations of about 2 mg/m3 in air and a respirable fraction of 25–30% were used. The effects of a variety of vibration frequencies and stroke lengths were tested in two modes (horizontal and vertical). At most frequencies and stroke lengths, vibration was found to have an insignificant effect on cyclone performance. Significant increases in cyclone collection efficiency were found for the horizontal mode, and significant decreases were found for the vertical mode, at specific frequencies and stroke lengths. These variations could be due to direct vibration effects, or may be artifacts caused by resonances in the aerosol chamber that are peculiar to the chamber configuration used.