Patent ID: 8157894

Claim:
A process to clean an air stream having particles of different sizes entrained therein, said process comprising: first removing a substantial portion of larger particles from the air stream by passing the air stream through an impact filter, including accelerating the air stream and particles to substantially similar velocities in a nozzle having a nozzle diameter and a nozzle outlet, directing the accelerated air stream and particles from the nozzle outlet toward an impact surface that is spaced from the nozzle outlet, separating the particles into classified steams of particles redirected by the impact surface, and collecting the substantial portion of larger particles in a trough by passing the substantial portion of larger particles through a trough entrance larger than the distance between the impact surface and the nozzle outlet; and thereafter removing a substantial portion of the smaller particles from the air stream by at least one of passing the air stream and the remaining particles from the impact filter through an electrostatic precipitator, passing the air stream and the remaining particles from the impact filter past a source of UV light, and passing the air stream and the remaining particles from the first mentioned impact filter through a second impact filter.