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 - 66 . Canceled.  
   
   
       67 . A powder spray booth comprising: 
 a booth floor;    vertical walls extending from said floor;    a powder overspray intake for drawing powder entrained air from an interior of the spray booth;    a vertically extending duct in communication with said overspray intake;    said duct having a wall portion facing an interior of the booth; said wall portion having one or more openings therein for aspirating air from the booth interior.    
   
   
       68 . The booth of  claim 67  wherein said wall portion forms part of a vertical wall of said spray booth.  
   
   
       69 . The booth of  claim 67  wherein said openings are asymmetrically spaced along said wall portion.  
   
   
       70 . The booth of  claim 67  comprising a powder recovery system in communication with said overspray intake.  
   
   
       71 . The booth of  claim 70  wherein said system comprises a cyclone.  
   
   
       72 . The booth of  claim 67  wherein said wall portion comprises a hinged door for access to an interior of said duct.  
   
   
       73 . The booth of  claim 67  comprising sliding doors that form part of a vertical wall extending from said floor.  
   
   
       74 . A powder spray booth comprising: 
 a booth floor having downwardly sloped portions;    a powder overspray intake for drawing powder entrained air from an interior of the spray booth;    said floor comprising a trough below said sloped portions with a diverter plate that overlays at least a portion of said trough to form a floor duct in communication with said powder overspray intake; and    a vertically extending duct in communication with said overspray intake;    said vertically extending duct having a wall portion facing an interior of the booth; said wall portion having one or more openings therein for aspirating air and overspray powder from the booth interior.    
   
   
       75 . The booth of  claim 74  comprising a source of pressurized air to blow off overspray powder from said sloped floor portions and said diverter plate during a spraying operation.  
   
   
       76 . The booth of  claim 75  wherein said pressurized air is pulsed.  
   
   
       77 . The booth of  claim 74  wherein said wall portion is moveable for a clearing operation.  
   
   
       78 . The booth of  claim 77  wherein said moveable wall portion comprises a hinged door.  
   
   
       79 . A method of collecting overspray powder from a powder spray booth during a spraying operation, comprising the steps of: 
 producing an air flow in the floor duct to transfer overspray powder through the floor duct and into a powder recovery system, and    aspirating air and overspray powder from an upper region of the booth into a vertically extending duct during a spraying operation.