Powder spray coating

A powder spray apparatus as claimed in any preceding claim wherein the powder recovery module includes suction means (20) for removing overspray powder from the booth and at least one exhaust duct ( 28) connected to the suction means (20) and communicating with the booth for passage of air-borne overspray powder.

A powder spray apparatus comprising a powder spray booth (2) having a floor, side walls and end walls, one or more powder spray devices (18) positioned with respect to the side walls to spray articles passed through the booth via openings in the end walls and a powder recovery module comprising separation means (24) for separating powder from a powder-air mixture, suction means (20) for removing overspray powder from the booth, an exhaust duct (28) connected to the suction means (20) and communicating with the booth (2) for passage of air-borne overspray powder, collection means (14) for collecting deposited air-borne overspray powder from the booth floor and a feed channel (22) connected to the suction means (20), wherein the collection means (14) moves the collected deposited overspray powder to the feed channel (22) through which it is passed under the action of the suction means (20) to the separation means (24) characterised in that the exhaust duct (28) forms part of the feed channel and in that means (62) is provided for adjusting the relative amounts of suction provided by the suction means (20) to respectively the air-borne overspray powder and the deposited overspray powder.

A powder spray apparatus as claimed in any preceding claim wherein two cyclone separators (24) are provided, one adjacent each end wall of the powder spray booth.

A powder spray apparatus as claimed in any preceding claim wherein the powder recovery module further comprises a filter module (52) for removal of fine powder particles entrained in air exhausted from the booth.

A powder spray apparatus as claimed in any preceding claim wherein the booth walls, floor and ceiling are formed from non-conductive material.

A method of operating a powder spray apparatus having a powder spray booth (2) including at least one powder spray device (8) for spraying articles passed through the booth, the method comprising-exhausting air from the booth by suction at a first extraction location (64) to withdraw air borne overspray powder via the first extraction location (64), collecting deposited overspray powder from the interior of the booth, transferring the collected deposited overspray powder to a second extraction location (18), withdrawing the collected deposited overspray powder in an air current by suction at the second extraction location (18), and separating the overspray powder from the air characterised in that the method includes varying the relative amounts of suction applied at the first and second extraction locations (64, 18) and therefore the relative amounts of suction applied to the air-borne overspray powder and the deposited overspray powder.