Filter system

Claim 1

A powder filtering system for environmental control at a workplace vent where powdered particles are diffused into ambient air, said system comprising suction means adjacent to the workplace for venting off any particle-laden ambient air from the workplace, the suction means comprising an air filter structure including a housing enclosing a compartment, a chamber, and a receptacle, a partition in the housing and separating the compartment and the chamber, a wall in the housing and separating the chamber and the receptacle, the partition and the wall having corresponding openings, air inlet means for introducing particle-laden air into the compartment and exhaust air outlet means communicating with the chamber for removing filtered air from the chamber, a conduit extending between the workplace vent and the air inlet, the air filter also comprising flexible tubular filters extending between corresponding openings in the partition and the wall, each tubular filter being composed of flexible material, means for shaking the tubular filter to dislodge deposited powder particles from the walls of the tubular filter and into the receptacle, the shaking means comprising a vibrating structure, a rigid frame within the chamber and around the tubular filters, and spaced rods extending across the frame and between the filters, and each tubular filter being separately attached to one of the spaced rods.