INNER SURFACE COATING METHOD AND APPARATUS OF HOLLOW TUBE

摘要

PURPOSE: To uniformly coat the interior surfaces of hollow tubular articles with a powder coating material by releasing a pneumatic transporting powder stream impressed with an electrostatic charge into the open end of the hollow tubular articles via a nozzle, applying the powder coating material to the interior surface thereof and sucking and collecting the excess powder with a collection shroud. CONSTITUTION: The nozzle assembly 1 moves back and forth in a rotating grounded vessel body 3 and adheres and applies the pneumatic transporting powder to the interior surface while releasing the pneumatic transporting powder previously impressed with the electrostatic charge as jet stream 14 from the two release orifices 9. The other open end 5b of the vessel body 3 is enclosed by the collection shroud 6 which sucks and removes the excess powder not adhered on the interior surface of the can body 3 by a pipe 17 connected to a vacuum source. The powder is then guided into a powder recycling unit to be recycled. The entire part of the interior surface of the article is thus uniformly coated and protected with the min. amt. of the powder.