Patent ID: 7608121

Claim:
A heating, ventilation and cooling system comprising; a heat exchanger for heat transfer with air passing there through, wherein said heat exchange has a front face oriented toward oncoming air flow and a bottom edge substantially perpendicular to said front face, a housing surrounding said heat exchanger and defining an air inlet adjacent to said front face of heat exchanger and an air outlet adjacent to said bottom edge of heat exchanger, wherein said air inlet is larger and than said air outlet, a plurality of rollers supported by said housing defining an L-shape, wherein the plurality of rollers includes two rollers defining the shorter portion of said L-shape adjacent to said bottom edge of heat exchanger, an endless sheet having an interior entrained about said rollers and extending in a path of overlapping movement over said air inlet and said outlet, wherein said endless sheet includes a cleaning reach defined by said endless sheet overlapping said two rollers adjacent to said bottom edge of heat exchanger, a drive mechanism for moving said sheet in said path; and a flow control for directing air exiting from said heat exchanger through said cleaning reach of said sheet. said sheet having filtering air passages there through permitting the air to flow through said sheet as said sheet filters foreign matter from the air flowing through said sheet.