Inside powder striping apparatus

Claim 1

A powder applicator for applying a coating stripe to the exterior of a longitudinal side seam of a tubular body moving along a tubular path and wherein said side seam is generally at the 12:00 o'clock position, said powder applicator comprising a supporting horn, longitudinally extending upwardly directed brushes carried by upper portions of said horn in transversely spaced relation and generally equally spaced on opposite sides of a vertical plane through a longitudinal axis of said horn, said brushes being positioned for engagement with the interior of a tubular body adjacent to said side seam thereof to limit the width of said coating stripe, feed means adjacent said horn for sequentially moving tubular bodies along said horn in closely spaced relation, and powder flow control means in an upper part of said horn and generally between said brushes, said powder flow control means including an elongated longitudinally extending channel defined by porous wall means, a powder applying nozzle opening into one end of said channel generally in the direction of tubular body movement, said nozzle being tilted slightly vertically for directing coating powder directly on a tubular body side seam area between said brushes, means for electrostatically charging said powder delivered to said nozzle for effecting initial adherence of a majority of the coating powder directly to tubular bodies with said channel forming catcher means for powder not initially adhering to tubular bodies, charging means in said channel for charging powder falling in said channel and again directing such powder upwardly towards said path of tubular body movement for application to tubular bodies, means for directing a gas through said wall means for continuously agitating powder within said channel, diverter means in said channel at the end thereof remote from said one end for directing powder reaching said channel remote end vertically out of said channel towards the path.