Spreader bar for application of pigment, paste or liquid to a moving paper web or drum has ultrasonic self-cleaning action

摘要

In a process to apply a coating or film of e.g. pigment, paste or liquid to a moving paper web or drum, the coating is spread by a spreader bar. During a self-cleaning cycle the spreader bar oscillates under the influence of an ultrasonic source. The oscillating spreader bar is supported at each end by bearings, and is agitated by an oscillating arm exposed to an ultrasonic source. The fluid or semi-fluid deposits sticking to the drum or spreader bar are loosened by the spreader oscillations. Further claimed is that the oscillating spreading bar enhances the uniformity of application during normal operating mode.