Power preconditioning for electrostatic application
AssigneeOwens-Illinois, Inc.
InventorsRussell W. Heckman, George A. Nickey
Life of this patent
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Abstract
Organic hygroscopic powders are preconditioned to render them free flowing and to facilitate their electrostatic application to preheated workpieces. The preconditioning technique includes drying the powder prior to electrostatic application to remove moisture and break up agglomerates using a fluidized bed drying process with concurrent mechanical agitation to form a substantially dry, free flowing powder.
Claims7
In the process for applying organic hygroscopic powder to coat a preheated glass container wherein said powder is electrostatically applied to said glass container in a powder application station and the adhered powder is subsequently thermally fused on said glass container to form a smooth coating, the improvement wherein said hygroscopic powder is preconditioned in a preconditioning zone prior to electrostatic application to said glass container by passing a stream of dry, inert gas having a dew point of less than about 35.degree. F. upwardly through a mass of said powder at a rate sufficient to suspend said powder in said stream as a fluidized bed and mechanically agitating said fluidized bed for a residence time sufficient to yield a substantially dry, free flowing powder, separating the free flowing powder from said stream by aspirating through an outlet disposed intermediate of open ends of a vertical conduit immersed in said bed, and then transferring said free flowing powder to the electrostatic application station.
Dependencies are inferred from the claim text.