| 摘要 |
A method and apparatus for coating a metal substrate with a finely divided powdered material, which method includes the steps of providing a supply of resin particles adjacent a coating zone, releasing a gentle flow of gas through the supply of resin particles to permit the particles to flow freely, delivering a uniform flow of particles to a comminuting site, releasing the fluid energy of a compressed gas to the flow of resin particles to impart sufficient momentum to said resin particles to reduce their average particle size to a very finely divided resin particle size of 10 microns or less, providing a flow of finely divided resin particles and diffusing the flowing gas to provide a substantially quiescent, slowly and upwardly moving gas stream to maintain the very finely divided resin particles segregated in a uniform cloud and to carry said cloud to the coating zone; confining said cloud of very finely divided resin particles in the coating zone, said particles having a diameter-to-weight ratio such that they will remain suspended in the substantially quiescent atmosphere of the coating zone; moving sheet metal stock to be coated in strip form through the coating zone; and providing an electric charging and depositing field terminating on the metal stock strip in the coating zone having a potential gradient sufficient to charge the finely divided resin particles and deposit said particles on the metal surface while the particles are in a repelling relationship with respect to one another thereby providing a uniform distribution of particles on the strip.
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