APPARATUS FOR COATING WITH ELECTROSTATICALLY CHARGED PARTICULATE MATERIALS

An improved control device for apparatus for coating articles with an electrostatically charged material in discrete form. The apparatus includes a nozzle having an inlet and a discharge outlet for the particulate material, an electrode for electrostatically charging the particulate material and at least one passage for directing a stream of vortex gas to impart a vortical motion to the particulate material discharged from the nozzle. A trigger on the apparatus operates first and second gas valves. The first valve controls a stream of gas to the vortex gas passages in the nozzle for controlling the pattern of the sprayed material and the second valve operates a pneumatic control to cause a high voltage to be applied to the electrode in the nozzle and to cause a pump to deliver to the nozzle inlet a stream of gas having the particulate material dispersed therein. In a preferred form, the trigger opens the first valve before the second valve and closes the second valve before the first valve. Provision is made for easily cleaning residual material from the pump, the nozzle and an interconnecting tube when changing the material to be sprayed.