IMPROVEMENTS IN AND RELATING TO POWDER SPRAY COATING

摘要

Apparatus for powder spray coating comprises means (4) for electrostatically-charging powder entrained in air, a conduit (6) for transporting the electrostatically charged powder from the charging means (4) to an internal chamber (12) in a spray head (8), the spray head (8) having at least one passage (16) from the internal chamber (12) to at least one nozzle (17) from which the powder is discharged, and a deflector (18) mounted externally of the spray head (8) and adjacent to the or each nozzle (17) to deflect the discharged powder into a flat spray pattern, the spray head (8) and the flat spray pattern being substantially symmetrical about a common longitudinal axis. The apparatus is particularly suitable for coating a large surface area, or a plurality of small objects hung in a planar array. Preferably multiple triboelectric type charging means (4) are used and a single pump is used to supply powder to the multiple charging means through a common distributor. After passing through the multiple charging means (4) the powder flows are then recombined and sprayed through a common nozzle.