Abstract: A known military tank is powered by a turbine engine having a large capac air filter unit; a fan is ordinarily employed to draw dust-laden air from the filter unit. Erosion of the fan blades by fast-moving dust particles is a problem. We have substituted for the fan an aspirator mechanism; fast moving combustion products flowing through the engine exhaust duct draw dust-laden air from the filter unit through a slot-like orifice in one wall of the duct.

Abstract: The process of removing embedded particulates from the pore surfaces of an ngine air cleaner (pleated paper type) is facilitated by blowing pulses (or jets) of compressed air through the filter media in the reverse flow direction. The invention relates to the employment of a fluidic oscillator for producing the air pulses. The oscillator is used in a switching mode such that alternate pulses are applied to different air cleaner sections. Overall objective is to achieve an effective cleaning action with a relatively small quantity of compressed air.

Abstract: Apparatus and method for supplying clean air to a closed vehicle from an ambient source of air polluted with particulate matter. This is accomplished by drawing in air as a hollow cylindrical flow, converting it to the form of a flat sheet of air having components of motion radial and tangential with respect to an axis, deflecting the air by more than 90.degree. to convert it to a conical whirling flow tapering toward the axis while retaining the tangential component of motion, purging from the flow particulate matter discharged centrifugally at the site of the deflection, skimming the conical flow to remove successive outer portions thereof together with the particulate matter centrifugally displaced thereinto, again deflecting the flow by more than 90.degree.

Abstract: An engine air cleaner comprising a cylindrical housing containing an annu perforate cleaning medium and a set of pre-cleaning baffles in the housing space surrounding the cleaning medium. The baffles maintain the dust-laden gas in a swirling condition, thereby centrifugally forcing heavy dust particles away from the cleaning medium surface. A scavenger fan removes heavy dust particles from the housing before such particles can contact the cleaning medium.