Powder coating systems

Abstract

A powder spray booth ( 2 ) with a powder recovery system having an overspray intake ( 18 ) communicating with the interior of the booth. A vertically extending duct ( 20 ) leads from the overspray intake to a powder recovery system such as, for example, a cyclone. The vertically extending duct may have doors ( 32 ) opening to the interior of the booth to provide access to the vertical duct for cleaning. The doors may have holes ( 120 ) to aspirate air from the booth interior to optimize air flow patterns within the booth. A diverter plate ( 26 ) within the booth ( 2 ) defines with the booth floor ( 10 ) a floor duct leading to the overspray intake ( 18 ). The diverter plate has apertures for allowing oversprayed powder to be collected through the plate. The diverter plate may be provided as two or more diverter plates held at different elevation levels within the booth to define a floor duct which is larger in parts of the floor duct which are closer to the overspray intake than parts of the floor duct which are farther from the overspray intake. The coating system may include an air assist which provides jets of air across a portion of the interior surface of the booth. The surface may be one or more sloped portions ( 22 ) of the floor and/or one or more portions of the diverter plate. The air supply may be pulsed to produce periodic bursts of air across the interior surface.

1 - 37 . (canceled) 
     
     
         38 . A powder spray system comprising a powder spray booth having side walls and end walls and a floor, one or more powder spray devices positioned with respect to the side walls to spray articles passed through the booth via openings in the end walls, and a powder recovery system having an overspray intake communicating with the interior of the booth, the powder recovery system including suction means for drawing overspray powder from the booth interior into the overspray intake, an air assist device comprising a source of air, and at least one plenum with at least two air outlets that are arranged to discharge air such as to move oversprayed powder which has collected on the floor towards inlet ducts, the inlet ducts collecting oversprayed powder which has been blown into the ducts by the air assist device, with powder collected in the inlet ducts being drawn through the overspray intake into the powder recovery system, and control means for controlling the source of air, wherein the control means control the source of air to provide pulses of air through the at least two air outlets of the at least one plenum. 
     
     
         39 . The powder spray system of  claim 38  wherein the source of air is a compressed air source, one or more fans or an air supply of the powder recovery system. 
     
     
         40 . The powder spray system of  claim 38  wherein the booth has a rectangular or circular cross-section. 
     
     
         41 . The powder spray system of  claim 38  wherein the pulses of air are directed across the booth floor through the at least two air outlets of the at least one plenum. 
     
     
         42 . The powder spray system of  claim 38  wherein the air assist device is located along the centre of the floor, the air outlets are arranged to discharge air towards the side walls of the booth, and the inlet ducts being provided along the side walls of the booth. 
     
     
         43 . The powder spray system of  claim 38  wherein the plenum is located along one of the side walls and the air outlets are arranged so that air discharged from the air outlets moves oversprayed powder toward the other side wall. 
     
     
         44 . The powder spray system of  claim 38  wherein there are two plenums, one located along each side wall, and the air outlets are arranged so that air discharged from the air outlets moves oversprayed powder towards the centre of the booth. 
     
     
         45 . The powder spray system of  claim 39  wherein the booth has a rectangular or circular cross-section. 
     
     
         46 . The powder spray system of  claim 39  wherein the pulses of air are directed across the booth floor through the at least two air outlets of the at least one plenum. 
     
     
         47 . The powder spray system of  claim 40  wherein the pulses of air are directed across the booth floor through the at least two air outlets of the at least one plenum. 
     
     
         48 . The powder spray system of  claim 39  wherein the air assist device is located along the centre of the floor, the air outlets are arranged to discharge air towards the side walls of the booth, and the inlet ducts being provided along the side walls of the booth. 
     
     
         49 . The powder spray system of  claim 40  wherein the air assist device is located along the centre of the floor, the air outlets are arranged to discharge air towards the side walls of the booth, and the inlet ducts being provided along the side walls of the booth. 
     
     
         50 . The powder spray system of  claim 41  wherein the air assist device is located along the centre of the floor, the air outlets are arranged to discharge air towards the side walls of the booth, and the inlet ducts being provided along the side walls of the booth. 
     
     
         51 . The powder spray system of  claim 39  wherein the plenum is located along one of the side walls and the air outlets are arranged so that air discharged from the air outlets moves oversprayed powder toward the other side wall. 
     
     
         52 . The powder spray system of  claim 40  wherein the plenum is located along one of the side walls and the air outlets are arranged so that air discharged from the air outlets moves oversprayed powder toward the other side wall. 
     
     
         53 . The powder spray system of  claim 41  wherein the plenum is located along one of the side walls and the air outlets are arranged so that air discharged from the air outlets moves oversprayed powder toward the other side wall. 
     
     
         54 . The powder spray system of  claim 39  wherein there are two plenums, one located along each side wall, and the air outlets are arranged so that air discharged from the air outlets moves oversprayed powder towards the centre of the booth. 
     
     
         55 . The powder spray system of  claim 40  wherein there are two plenums, one located along each side wall, and the air outlets are arranged so that air discharged from the air outlets moves oversprayed powder towards the centre of the booth. 
     
     
         56 . The powder spray system of  claim 41  wherein there are two plenums, one located along each side wall, and the air outlets are arranged so that air discharged from the air outlets moves oversprayed powder towards the centre of the booth.