Method and apparatus for ultrasonic screen cleaning in a particulate delivery system

The present invention relates to particulate material delivery and screening, but more particularly to a method and an apparatus that cleans and prevents adhesion of fine particles or powders to a mesh during screening operations. An improvement for use in a fine particle delivery system that separates particulate material according to particle size, such as a toner screener used in an electrophotographic imaging machine. The fine particle delivery system includes an intake duct that receives particulate material, a screen that filters the materials as the particles move or rotate about the screen, and a pair of opposed ultrasonic transducer assemblies that excite the screen to dislodge particulate material adhering to the screen mesh. Each transducer assembly includes a transducer, a rigid metallic membrane coupled to transducer to efficiently deliver ultrasonic waves to the screen, and a mounting mechanism that supports the transducer assembly. A channel embedded with the mounting mechanism protects electrical wiring the powers the transducer from a potentially explosive environment of particulate material during screening operations. The mounting mechanism also provides convenient retrofitting of the transducer assembly with existing particulate screening systems or a pivotal mounting connection with a frame of the particulate delivery system to provide a screen removal clearance for servicing.