Apparatus for powder coating welded cans
First Claim
1. A system for electrostatically coating at least a portion of the interior surface of hollow container bodies moving along a predetermined path with a coating powder, said system comprising:
- a) a powder coating gun for spraying air-entrained coating powder within said hollow container bodies to form a coating of said coating powder on said at least a portion of the interior surface of said hollow container bodies, said powder coating gun being mounted to a downstream end of a welding arm of a can forming machine;
b) a delivery passage extending through said welding arm for transporting said air-entrained coating powder through said welding arm, said delivery passage connected at an upstream end to a densifer and at a downstream end to said powder coating gun for supplying said air-entrained coating powder to said powder coating gun; and
c) the densifer being connected to said delivery passage for venting off air and coating powder from said air-entrained coating powder prior to delivering said coating powder to increase the flow rate of coating powder flowing through said delivery passage to said powder coating gun.
1 Assignment
0 Petitions
Accused Products
Abstract
Methods and apparatus are disclosed for spraying powder into the interior of welded hollow can bodies from a spray gun mounted to the welding arm of a can forming machine. The spray gun can either apply a stripe of highly charged powder on the welded seam areas of hollow can bodies, or can simultaneously apply a coating of powder having a first thickness on the longitudinally welded seam areas and a second thickness less than the first thickness on the remainder of the interior surface. Air is vented off from the powder flow being transported through the welding arm so that the powder to air ratio is increased. Air is introduced at the downstream end of the welding arm to provide a suction force to help draw the powder flow through the welding arm and to increase the velocity of the powder flow for better tribo charging of the powder in the gun and to improve spray pattern stability. A flow of cleaning air through the powder spray gun prevents powder from collecting on the front surface of an offset nozzle secured to the spray gun. The gun assembly is affectively grounded to prevent arcing, and has an exterior shape which has been geometrically configured to improve powder coating of the can.
55 Citations
19 Claims
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1. A system for electrostatically coating at least a portion of the interior surface of hollow container bodies moving along a predetermined path with a coating powder, said system comprising:
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a) a powder coating gun for spraying air-entrained coating powder within said hollow container bodies to form a coating of said coating powder on said at least a portion of the interior surface of said hollow container bodies, said powder coating gun being mounted to a downstream end of a welding arm of a can forming machine; b) a delivery passage extending through said welding arm for transporting said air-entrained coating powder through said welding arm, said delivery passage connected at an upstream end to a densifer and at a downstream end to said powder coating gun for supplying said air-entrained coating powder to said powder coating gun; and c) the densifer being connected to said delivery passage for venting off air and coating powder from said air-entrained coating powder prior to delivering said coating powder to increase the flow rate of coating powder flowing through said delivery passage to said powder coating gun. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification