Patent ID: 8097050

Claim:
A vacuum apparatus rotatable about a rotational axis, for removing contamination from an air filter screen, comprising: an asymmetrical vacuum arm having a center hub for supporting the arm for rotation about the rotational axis in at least substantially parallel proximity to the air filter screen, the vacuum arm including an elongate hollow first arm portion extending a first distance radially outwardly from the hub, and an elongate hollow second arm portion extending a second distance radially outwardly from the hub, wherein the first and second arm portions extend in opposite directions, further wherein the second distance is greater than the first distance, the first arm portion including an elongate first vacuum orifice oriented to face the air filter screen and having a first radial extent extending radially outwardly to a radial outer end thereof, the second arm portion including an elongate second vacuum orifice oriented to face the air filter screen and having a second radial extent extending from a radial inner end thereof to a radial outer end thereof, the radial outer end of the first vacuum orifice and the radial inner end of the second vacuum orifice being located at about an equal radial distance from the rotational axis.