POWDER SPRAY APPARATUS FOR SPRAYING EXTERIOR CAN BOTTOMS

摘要

Apparatus for spraying powder onto an exterior surface of a can bottom (A) includes a supply of powder (14), a powder spray gun (12) that receives powder from the supply and produces a powder spray directed towards a can bottom, and a control device (40) that shapes the powder spray and collects overspray. A powder collection system (20) is used for recycling substantially all of the powder spray back to the powder supply, thereby increasing the production of fines. In a first embodiment, the control device is realized in the form of an airflow amplifier that draws a vacuum to produce a substantial air movement in the region of the can bottom. This air movement constrains the powder spray to flow within a relatively well-defined envelope. Powder overspray is collected by the amplifier and blown into a powder collection system. In a further embodiment, a deflector sleeve is provided about the gun nozzle to direct secondary powder fines into a well defined more homogenous spray pattern.