Coating of substrates with particle materials

Claim 1

Apparatus for electrostatically applying a coating of a particle material to a substrate to which a settable adhesive has been applied, the apparatus comprising a container for a stock of particle material; a single metering means comprising a chamber supplied with particle material from the container and comprising a base and an upstanding peripheral wall, and a power rotatable paddle wheel having blades which are adapted to sweep the volume of the chamber on rotation of the paddle wheel and between adjacent blades there being defined compartments, each adapted to contain a predetermined amount of particle material, the paddle wheel having an axis of rotation which is disposed vertically, said chamber having two alternatively openable exits, one exit being disposed in the base and the other exit being disposed in said upstanding peripheral wall, a manually portable discharge head being provided in communication with said other exit, and said one exit constituting a downwardly directed discharge head; said single metering means serving to meter the amount of particle material supplied to the discharge heads; the apparatus further including an electrostatic generator; main electrode means electrically connected to said generator and disposed in said chamber to electrically charge the particle material therein; and subsidiary electrode means electrically connected to said generator and associated with said portable discharge head.