Controlling cyclone efficiency with vacuum interface

Abstract

Powder overspray that is extracted from a spray booth is recovered back to a powder supply that is used to supply powder to the spray guns inside the spray booth. The powder overspray extracted from the booth is separated from the high flow air stream by a separator such as a cyclone separator. The powder falls into a transfer pan and a vacuum is used to convey the powder from the transfer pan to a vacuum receiver. The powder is then discharged to the feed hopper in the feed center. The use of a vacuum to convey powder from the cyclone to the feed center in effect permits substantially all of the powder overspray to be recovered from the spray booth directly to the feed hopper with minimal dwell or residence time within the cyclone or vacuum receiver subsystems during a spraying operation. The receiver can be rotated for easy cleaning, and the vacuum line cleaned by one or more cleaning elements drawn through the vacuum line.

1 . Powder recovery apparatus for a powder coating spray system, comprising: 
 a powder spray booth;    a cyclone having an inlet thereto that receives powder entrained in air from said spray booth wherein said cyclone operates to separate powder from the air; said cyclone having an outlet for recovering said separated powder and an exhaust for air;    a conduit with first and second ends that connect the cyclone outlet to a container; and    a negative pressure source coupled to said cyclone outlet by said conduit;    said negative pressure source producing a negative pressure within said conduit from said first end thereof to said second end thereof that causes a flow of powder from said cyclone outlet to said container.    
   
   
       2 . The apparatus of  claim 1  wherein said cyclone operates at a static pressure and said negative pressure source produces an induced air volume that is sufficient to draw powder from said cyclone outlet to optimize powder recovery.  
   
   
       3 . The apparatus of  claim 1  wherein said negative pressure source comprises a vacuum pump.  
   
   
       4 . The apparatus of  claim 3  wherein said vacuum pump is coupled to said container; said container being coupled to said cyclone outlet.  
   
   
       5 . The apparatus of  claim 4  wherein said container comprises a receiver having a filter that separates powder from said induced air flow.  
   
   
       6 . The apparatus of  claim 5  wherein said receiver is coupled to said cyclone outlet by a pipe.  
   
   
       7 . The apparatus of  claim 6  wherein said vacuum pump, receiver and pipe provide a closed air-tight system coupling the cyclone outlet to said negative pressure source.  
   
   
       8 . The apparatus of  claim 1  comprising a blower coupled to said exhaust to draw said powder entrained air into said cyclone at said cyclone inlet, said blower comprising a filter that separates powder from exhaust air.  
   
   
       9 . The apparatus of  claim 1  wherein said cyclone operates at a static pressure of at least 7 inches water column and said negative pressure source produces an induced air volume of at least 95 cfm.  
   
   
       10 - 27 . (canceled)