Improvements in and relating to powdered coatings

摘要

In a method and apparatus of coating a continuously moving metal strip e.g. steel with a powder such as A1 powder (120 mesh to dust) the powder is fed from a hopper to a metering device such as a rotating roll with a number of spaced circumferential grooves which receive the powder and discharge the powder as a series of streams on to a vibrating screen where the powder is electostatically charged prior to dispersal on the electrically earthed moving strip. According to Fig. 1 (not shown) the powder is stored in a hopper 3 comprising a steel retaining blade 16 bearing on metering roll 4 and a compacting blade 17 which forces the powder flowing from the hopper into the grooves 12 on the metering roll as the roll rotates. The powder in the hopper is agitated by a vibrator 19 and a scraper 21 removes excess powder adhering to the roll 4. The speed of rotation of roll 4 determines the volume of powder and this is discharged from the grooves by fingers 23. The powder streams are diffused on vibrating screen 5 which is electrically charged to 30kV and then are attracted to the moving earthed strip S.ALSO:In a method and apparatus of coating a continuously moving metal strip e.g. steel with a powder such as A1 powder (120 mesh to dust) the powder is fed from a hopper to a metering device such as a rotating roll with a number of spaced circumferential grooves which receive the powder and discharge the powder as a series of streams on to a vibrating screen where the powder is electrostatically charged prior to dispersal on the electrically earthed moving strip. According to Fig. 1 (not shown) the powder is stored in a hopper 3 comprising a steel retaining blade 16 bearing on metering roll 4 and a compacting blade 17 which forces the powder flowing from the hopper into the grooves 12 on the metering roll as the roll rotates. The powder in the hopper is agitated by a vibrator 19 and a scraper 21 removes excess powder adhering to the roll 4. The speed of rotation of roll 4 determines the volume of powder and this is discharged from the grooves by fingers 23. The powder streams are diffused on vibrating screen 5 which is electrically charged to 30KV and then are attracted to the moving earthed strip S.