Apparatus and methods for in-line cleaning of contaminant-coated hangers

Abstract

Devices and methods for continuous cleaning of contaminant-coated hangers or racks by removing the overspray contaminant that is detrimental to the powder coating operation. Exemplary cleaning systems use radio frequency (RF) energy to heat the overspray coating and soften it. The coating is heated to an intermediate level that is less than the incineration point, wherein the coating would be reduced to ash.

1 . An apparatus for removing powder coating residue from an object comprising: 
 a heater to heat powder coating residue coating the object to a temperature sufficient to soften the residue but not sufficient to incinerate the residue; and    a residue cleaner for removing softened residue from the object.    
   
   
       2 . The apparatus of  claim 1  wherein the heater heats the object such that an outer portion of the object is heated to a temperature within the range from about 500° F. to about 750° F.  
   
   
       3 . The apparatus of  claim 1  further comprising an in-line conveyor system to convey articles past the heater and the residue cleaner, the conveyor system comprising: 
 a moveable chain carried on a rail; and    a hanger retained upon the chain for removably supporting articles to be powder coated.    
   
   
       4 . The apparatus of  claim 1  wherein the residue cleaner comprises a brush.  
   
   
       5 . The apparatus of  claim 1  wherein the object to be cleaned comprises a hanger.  
   
   
       6 . The apparatus of  claim 1  wherein the heater comprises an induction coil unit.  
   
   
       7 . A system for removing coating material from hangers suspended from an in-line conveyor system used to move articles through a zone for applying coating to the articles, the system comprising: 
 a hanger heater for heating a hanger to a temperature sufficient to heat coating material on the object to a temperature sufficient to soften the coating but not sufficient to incinerate the coating; and    a residue cleaner for physically removing heated coating material from the hanger.    
   
   
       8 . The system of  claim 7  wherein the hanger heater comprises an induction heating coil adapted to heat the hanger to a temperature such that an outer surface of the hanger reaches a temperature in the range from about 500° F. to about 750° F. to soften coating accumulated on the hanger but not incinerate it to ash.  
   
   
       9 . The system of  claim 7  wherein the residue cleaner comprises: 
 a rotatable wire brush head; and    a rotary motor for rotating the brush head.    
   
   
       10 . The system of  claim 7  further comprising a hanger guide to orient the hanger to pass within a predetermined distance of the hanger heater.  
   
   
       11 . The system of  claim 10  wherein the hanger guide comprises a moving friction belt.  
   
   
       12 . The system of  claim 10  wherein the predetermined distance is from about ⅛ inch to about ⅜ inch.  
   
   
       13 . A method for removing coating material from hangers suspended from an in-line conveyor system used to move articles through a zone for applying coating to the articles, the method comprising the steps of: 
 heating a hanger to a temperature such that the outer surface of the hangers reaches a temperature in the range from about 500° F. to about 750° F. to soften coating accumulated on the hanger but not incinerate it to ash; and    removing the coating accumulated on the hanger.    
   
   
       14 . The method of  claim 13  wherein the step of heating the hanger further comprises heating the hanger until the outer 5-10 thousandths of an inch of the surface of the hanger reaches a temperature in the range from about 500° F. to about 750° F.  
   
   
       15 . The method of  claim 13  wherein the step of heating the hanger further comprises moving the hanger to a predetermined distance from a hanger heater that is in a range from about ¼ inch to about 1 inch.  
   
   
       16 . The method of  claim 15  wherein the hanger is moved to the predetermined distance for a predetermined period of time that is from about 4 to about 8 seconds.  
   
   
       17 . The method of  claim 16  wherein the step of heating the hanger further comprises contacting the hanger with a hanger guide to move the hanger to the predetermined distance for the predetermined period of time.