Air filter assembly having non-cylindrical filter elements, for filtering air with particulate matter

An air filter assembly comprising

• (a) a housing including an air inlet, an air outlet, a spacer wall separating said housing into a filtering chamber and a clean air chamber;
• (i) said air inlet providing a dirty air volume to said air filter assembly, said dirty air volume having an air flow direction and an air speed;
• (ii) said spacer wall including a first air flow aperture therein;
• (b) a first filter construction positioned in air flow communication with said first air flow aperture in said spacer wall;
• said first filter construction including an extension of filter media defining a filter construction inner clean air chamber;
• (i) said first filter construction having a cross-sectional area, when taken parallel to said first air flow aperture, said cross-sectional area having a long axis perpendicular to a short axis;
• (ii) said first filter construction having a width along said long axis and a width along said short axis, said long axis positioned parallel to said air flow direction, and wherein a ratio of the short axis to the long axis is at least about 0.5 and less than 1.0;
• (iii) said first filter construction further having a first surface area defined by said extension of filter media;
• wherein said dirty air volume is at least 10 percent greater than a second dirty air volume, and further wherein said air speed is equal to a second air speed, the second dirty air volume and the second air speed being in a second air filter assembly, the second air filter assembly comprising:
• (c) a second housing including an air inlet, an air outlet, a spacer wall separating the housing into a filtering chamber and a clean air chamber;
• (i) the air inlet providing the second dirty air volume to the air filter assembly, the second dirty air volume having an air flow direction and the second air speed;
• (ii) the spacer wall including a second air flow aperture therein;
• (d) a second filter construction positioned in air flow communication with the second air flow aperture in the spacer wall;
• the second filter construction including an extension of filter media defining a second filter construction inner clean air chamber;
• (i) the second filter construction having a cross-sectional area, when taken parallel to the first air flow aperture, the cross-sectional area having a long axis perpendicular to a short axis;
• (ii) the second filter construction having a width along the long axis and a width along the short axis, the long axis width being equal to the short axis width;
• (iii) the second filter construction further having a second surface area defined by the extension of filter media, the second surface area equal to said first surface area of said first filter construction.

A method of filtering dirty air comprising:

• (a) providing a housing including an air inlet, an air outlet, a spacer wall separating the housing into a filtering chamber and a clean air chamber, the filtering chamber having a volume of no greater than about 176 cubic feet;
• (b) inputting at least 550 cubic feet per minute of dirty air, the dirty air having a contaminant concentration of at least 1 grain per cubic foot, into the filtering chamber via the air inlet;
• and
• (c) filtering the dirty air by passing the dirty air from the filtering chamber through a non-cylindrical filter construction into the clean air chamber, the filter construction having a cross-sectional area having a long axis perpendicular to a short axis, a ratio of the short axis to the long axis being at least about 0.5 and less than 1.0.