Patent ID: 8162570

Claim:
A spraycoating powder feed apparatus, comprising: a control unit; a powder pump having a first powder hookup and a second powder hookup, and a reversible feed direction, the powder pump configured to pneumatically move powder from the first powder hookup to the second powder hookup, or to pneumatically move powder from the second powder hookup to the first powder hookup; a conduit switch comprising at least three conduit connections, the conduit switch configured to alternately link a first conduit connection to either a second conduit connection or to a third conduit connection, wherein the first conduit connection of the conduit switch is connected to the second powder hookup of the powder pump; a powder feed tube connected to the first powder hookup of the powder pump; and a fluidizing unit fitted at a lower end of the powder feed tube, the fluidizing unit having at least one fluidizing air dispensing element porous to compressed air but impermeable to powder wherein the powder pump and the conduit switch are switched by the control unit in a mutually dependent manner between a forward powder conveyance in which the first conduit connection of the conduit switch is exclusively linked to the second conduit connection but not to the third conduit connection, and a reverse powder conveyance in which the first conduit connection of the conduit switch is exclusively linked to the third conduit connection but not to the second conduit connection.