Pneumatic separator, filter and particle conveying system

Claim 1

In copying machines utilizing particulate toner having a toner applying area therein, a pneumatic conveyance system comprising: a. pickup means, having an inlet positioned adjacent the toner applying area of the copying machine for removing loose toner particles from emerging copies, and an outlet; b. a particle settling chamber having at least some opening to atmosphere and having an inlet and an outlet, said settling chamber being positioned adjacent said copying machine in communication with the toner applying area; c. a pneumatic flow producing pump having an inlet and an outlet; d. centrifugal separating means having an inlet, a gas outlet and a scavenging-flow outlet; e. first conduit means, connected between the pump inlet, the outlet of the pickup means and the outlet of the particle settling chamber, for producing flow at sub-atmospheric pressure through the pickup means and flow at sub-atmospheric pressure through the particle settling chamber to prevent particles from escaping through said openings therein; f. second conduit means connected between the inlet of the centrifugal separating means and the pump outlet for conducting particles and gas from the pickup means and the particle settling chamber into the centrifugal separating means, said separating means acting to separate the majority of said particles from the main pneumatic flow, the main pneumatic flow egressing from said centrifugal separating means through said gas outlet and the separated particles egressing from said centrifugal separating means through said scavenging-flow outlet; and g. third conduit means connected between the scavenging-flow outlet and the inlet of the particle settling chamber for conducting separated particles from the centrifugal separating means into the particle settling chamber.