Abstract: A pneumatic powder collector for determining the transfer efficiency of a powder spray system comprises a funnel for directing powder into a sealed collection chamber. A vacuum is drawn on this chamber by an air flow amplifier having an air flow inlet open to the chamber and an exhaust open to atmosphere. Contained within the chamber there is an air permeable powder collection bag having an inlet open to the funnel so that air entrained powder drawn into the funnel is collected in the bag. The amount of vacuum drawn on the chamber is controlled by a pressure regulator through which high pressure air is supplied to the air flow amplifier so that the vacuum is just sufficient to pull all powder sprayed by a spray gun of the spray system into the chamber without increasing the flow of powder from the gun.

Abstract: A nozzle assembly for an electrostatic powder spray gun is disclosed. The powder spray gun includes an electrically non-conductive barrel through which a high voltage electrical path passes. The nozzle assembly is mounted in the open forward end of the barrel and includes a sleeve located on the center axis of the barrel for directing a flow of a pressurized gas, e.g., air, through the center of the nozzle assembly, a nozzle surrounding the sleeve defining an annular flow path for powder spray coating material encircling the flow of pressurized air and an air deflector cap for directing the pressurized air radially outwardly and into the flow of powder spray coating material being emitted from the nozzle. The air impacts the powder coating material to form a conical spray pattern of coating material. The gun also includes an electrode extending out of the nozzle assembly for electrostatically charging the powder. The nozzle assembly eliminates mechanical powder deflectors and the problems attendant therewith.

Abstract: An electrostatic powder coating system for selectively spraying any one of a plurality of different pulverant powder materials from a common spray gun without the necessity for physically disconnecting or reconnecting the spray source of the different pulverant materials to the common gun. This system includes the common spray gun, a plurality of powder material reservoirs and associated venturi pumps connected to a common manifold block. That manifold block is also connected to a source of purging air flow. Internally of the manifold block there are pinch valves operable to selectively connect and disconnect each of the different powder material reservoirs and the purging air flow to the common spray gun. Additional pinch valves separate the material reservoirs from the venturi pumps associated with each reservoir.