Electrostatic rotary atomizing spray device

Abstract

A rotary atomizer has an internal power supply in the atomizer housing about which is passed cooling air. The air then flows out of the atomizer housing in a twisting direction as vectored air in the same direction of rotation as the atomizer head to eliminate any vacuum condition around the atomizer head and to provide shaping control of the coating being sprayed. Exhaust air from an air turbine motor driving the atomizer head is directed around the outside surface of the atomizer housing to prevent the liquid coating from wrapping back and accumulating onto the atomizer housing. A speed sensing system is mounted in the atomizer housing and utilizes both magnetics and optics for accurately measuring the rotational speed of the air turbine motor in the presence of high electrostatic charge and RF fields from the internal power supply. The power supply is disposed within the atomizer housing about the turbine motor. The atomizing head, in one embodiment, incorporates an insert which divides the flow of coating material into a plurality of individual streams to improve the atomization of the coating material from the atomizing head. In another embodiment, an insert is located in the atomizing head to insure that the front flow surface of the atomizer head remains wet during operation so that the atomizing head is easier to clean. The power supply is ring shaped and encircles the turbine and the paint flow passage through the turbine. An intrinsic safety barrier is provided to supply electrical power to the power supply. The intrinsic safety barrier is incorporated into the feedback loop of a voltage regulator.