Abstract: The invention provides a filter apparatus for use in air pollution control which includes at least one hollow filter assembly disposed in a hopper and having an open upper end registering with a wall opening. Contaminated air is introduced into the hopper through an inlet and is caused to flow into an exhaust chamber through the filter and the opening. The filter apparatus includes an end plate supporting the filter assembly and sealing the lower end of the filter assembly. The filter apparatus also includes a nozzle spaced above the filter assembly for selectively directing a reverse pulse of air into the open upper end of the filter such that the reverse air pulse enters the filter assembly and flows through the filter medium in the reverse of the direction of contaminated airflow to thereby remove accumulated contaminants from the filter medium.

Abstract: A method for making a precision wound tubular shaped filter cartridge wherein a filter medium comprising a roving is wound about a central foraminous core to provide a base inner and an outer helical winds of roving each provided with pluralities of both axial and circumferential flow passages wherein the circumferential flow passages of the inner and outer wind are radially aligned at the interface of the winds to provide unrestricted flow paths between the inner and outer wind.

Abstract: Cartridge type filters are suspended in hopper. Contaminated air flows into the hopper, passes through the filters and clean air is removed through an exhaust duct. Periodically a reverse stream of compressed air is directed through an inductor unit into each filter from the exhaust side to pressurize the filters and clean contaminants from the outer surface of the filter medium. With reference to the flow of the reverse stream, the walls of the inductor flare generally on a taper upstream from a restricted throat to a generally bowl-shaped section which flares to a diameter greater than the diameter of the throat. The bowl-shaped section extends upstream to merge with an arcuate section of a bell-mouth inlet which is convex to the exhaust chamber and terminates in a lateral flanged end. The throat is generally arcuate and convex to the inductor interior.