Apparatus for powder coating welding cans
First Claim
1. A system for coating the interior surface of a hollow container body moving along a predetermined path through a can forming machine with a powder coating material, the can forming machine having a welding arm, comprising:
- a) a delivery passage extending through said welding arm for transporting a flow of air-entrained powder from a source of said powder;
b) a coating gun mounted to said welding arm and connected to said delivery passage, said coating gun spraying air-entrained powder within said hollow container body to form a coating of said powder on said interior surface of said hollow container body; and
c) an offset nozzle mounted within an outlet opening of said powder gun to form a continuous annular spray opening with an enlarged portion for applying powder onto said interior surface of said container body.
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. A collector hood surrounds an input conveyor on which cans are transported while being spray coated and an output conveyor which removes the cans at a higher speed than at which they traveled on the input conveyor. The collector hood has two operating conditions for collecting oversprayed powder from between the cans during the spraying operation or directly from the gun when the cans are not being sent down the line.
51 Citations
13 Claims
-
1. A system for coating the interior surface of a hollow container body moving along a predetermined path through a can forming machine with a powder coating material, the can forming machine having a welding arm, comprising:
-
a) a delivery passage extending through said welding arm for transporting a flow of air-entrained powder from a source of said powder; b) a coating gun mounted to said welding arm and connected to said delivery passage, said coating gun spraying air-entrained powder within said hollow container body to form a coating of said powder on said interior surface of said hollow container body; and c) an offset nozzle mounted within an outlet opening of said powder gun to form a continuous annular spray opening with an enlarged portion for applying powder onto said interior surface of said container body. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
-
Specification