Patent ID: 8657928

Claim:
An air cleaning method comprising: drawing heavier-than-air particulate debris laden air into an inlet at a first axial end of a powered air precleaner comprising a motor-driven fan with a fan blade located in a flow path in the air precleaner, the air precleaner extending along a longitudinal axis between the first axial end and a second axial end, flowing the particulate debris laden air along the flow path in the air precleaner from the inlet to the second axial end where the flow path is retroflexed en route to an outlet intermediate the axial ends, rotating the flow of the debris laden air about an axis in the air precleaner to form a stratified rotating flow with heaviest particles in outermost orbits of the stratified rotating flow, ejecting particulate debris laden air from the outermost orbits of the stratified rotating flow through at least one ejector port of the air precleaner, filtering air from innermost orbits of the stratified rotating flow through an air filter of the air precleaner extending along said axis within the rotating flow, flowing the filtered air through an internal passage in the air filter which forms a portion of the retroflexed flow path toward the outlet of the air precleaner, including utilizing a removable, disposable air filter cartridge in the air precleaner, wherein the air filter for said filtering and an end section of the air precleaner forming the second axial end thereof closing one end of the internal passage of the air filter and including the at least one ejector port for said ejecting are integral parts of the removable, disposable air filter cartridge of the air precleaner.