Engine air cleaner

In an engine air cleaner comprising a housing that includes a cylindrical side wall (10) defining the housing axis, and first and second end walls (11 and 13), an annular porous cleaning medium (12) disposed within said housing, the outer peripheral surface of the cleaning medium being spaced radially inwardly from the cylindrical housing side wall to define an annular inlet chamber therebetween;

• said first end wall (11) having a large number of circumferentially spaced air inlet guide louvers acutely angled to a radial plane taken at right angles to the housing axis, whereby dust-laden air is caused to take a helical swirling motion as it moves into the inlet chamber, a dust scavenger outlet tube (14) having a tangential connection with the cylindrical side wall at a point near said second end wall (13), and a scavenger exhaust fan (40) connected to the outlet tube for drawing at least some of the dust particles out of the air cleaner before such dust particles can make contact with the cleaning medium:
• the improvement comprising a baffle means extending within the annular inlet chamber to confine the air-dust layer adjacent the housing side wall to a helical flow pattern while said layer is advancing toward the second end wall;
• said baffle means comprising a perforated circular wall structure (50) extending from the second end wall toward the first end wall within the inlet chamber, said perforated wall structure subdividing said inlet chamber into an outer annular space (56) adjacent the housing side wall and an inner annular space (54) adjacent the cleaning medium, the perforations in said wall structure being defined by vanes (52) acutely angled outwardly from the general plane of the wall structure, whereby swirling fluid has an easy mode of entry from the inner space to the outer space but a difficult mode of entry from the outer space to the inner space;
• said vanes being oriented in the same circumferential direction as the aforementioned louvers, whereby the vanes present minimal resistance to the swirl pattern generated by the louvers.