Abstract: Apparatus for powder spray coating comprises means for electrostatically-charging powder entrained in air, a conduit for transporting the electrostatically charged powder from the charging means to a spray head adapted to discharge the powder in a hollow conical spray pattern, wherein the spray head comprises means for diverting at least a portion of the flow of charged powder towards a spray device mounted to the spray head and adapted to discharge powder in a substantially uniform conical spray pattern, the spray head, spray device and the hollow conical and conical spray patterns being substantially symmetrical about a common longitudinal axis. The apparatus is particularly suitable for coating a large surface area. Preferably multiple tribo-electric charging means are used and a pump is used to supply powder to the multiple charging means through a common distributor. After passing through the multiple charging means the powder flows are then recombined and sprayed through a common spray apparatus.

Abstract: 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.

Abstract: A hand held powder spray gun is disclosed. The spray gun includes a casing enclosing a plurality of helical charging ducts mounted on parallel cores. The ducts receive powder from a diffusor mounted in a depending gun handle and discharge charged powder towards a nozzle mounted at one end of the casing.

Abstract: A powder sprayer to be charged electrostatically, comprising a plurality of elongated, curved charging ducts made of an electrically non-conducting material and coated with an electrically-conducting layer over part of their length and connected via a lead to earth or to a voltage source, so that when the sprayer is used the powder material is charged by close contact with the internal walls of the ducts as it passes through the charging ducts. The ducts are curved around to form at least one loop and/or undulation with their longitudinal center plane extending substantially in the supply direction of the powder.