Rotary atomizer coater

DETAILED DESCRIPTION The invention relates to an improved rotary atomizer coater which includes a longitudinally extending housing having a front end and a rear end.
A bell cup having an interior open to atmosphere is rotatably mounted adjacent the front end of the housing.
The bell cup defines an inlet opening at its rear end.
A coating supply means is mounted within the housing.
The coating supply means includes a fluid discharge tip which extends through the bell cup inlet opening for supplying charged coating fluid directly to the bell cup interior.
A power supply is mounted within the housing.
A charging electrode is positioned adjacent the fluid discharge tip and an electrical resistor means is mounted between the charging electrode and the power supply means.
Preferably, spring means are provided to urge the resistor, the electrode and the power supply into desired electrical communication.
In one embodiment, a turbine driven shaft is rotatably mounted in the housing.
The front end of the shaft includes an inner outwardly tapered surface and an opposed outer threaded surface.
The rotary bell cup has a conical wall defining an outer tapered surface which mates with the outwardly tapered surface of the shaft.
The bell cup preferably includes a rearwardly directed circular wall attached to the conical wall.
The circular wall has an inner surface which define threads which mate with the outer threaded surface of the shaft.
This design ensures correct concentric mounting of the bell cup relative to the shaft and also shortens the overall length of the bell cup and its mounting.
Extra length and weight of any bell cup magnifies any radial imbalances due to the extended moment created by an overhanging bell cup mass.
In one embodiment of the invention, the rotatable shaft is mounted by an aluminum air bearing assembly.
The aluminum air bearing assembly has an inner surface which is anodized.
A layer of a tetrafluoroethene homopolymer, such as a TEFLON material, is impregnated into the open cells of the anodized aluminum inner surface adjacent the shaft