Abstract
Ground silica dust (Mg = 1.3 μ, σg — 1.7) was deposited on Tyler 100 mesh screen at velocities from 3.8 to 27 fps. Particles adhering to the screen were then blown off by filtered air at velocities greater than deposition. Air drag on particles submerged in the laminar boundary layer was calculated from a simple irrotational fluid flow model and compared to particle adhesion force determined in a companion study. Air drag calculated in this manner failed to account for observed particle re-entrainment. Particle re-entrainment, defined in terms of screen pressure loss, was more difficult to achieve as deposition velocity increased. A blowoff velocity of 132 fps, based on screen free cell area, removed essentially all adhering dust from a single screen. During both deposition and dust blowoff procedures, the collector acted as a particle agglomerator and increased particle size by a factor of approximately 2x.