Abstract: The vertically suspended filter bags of a dust collector are periodically shaken in a bi-modal manner, to removed adhered dust. Repetitious motions applied to the closed bag bottoms are comprised of a long lifting stroke, to partially fold the bags, followed by one or more short strokes of higher impulse, to simulate a rapping or hammering. Apparatus which effects the process includes a motor driven cam that lifts, and then drops, a shaker bar mounted transversely to the bag bottoms, and a device for stopping the cam in a position which leaves the bags hanging freely for further collection of particulate.

Abstract: A fume and dust collector system is comprised of a semi-rigid tubular filter compressively held against a sub-base by a beam. To dislodge accumulated particulate, a combination of gravity hammer rapping of the beam compressively loads the filter wall and pulses of air discharged into the filter interior tension the wall. The filter is removed through the top of the enclosure and particulate is removed through a drawer at the bottom.