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US 5,695,826 AGranted
Electrostatic powder coating apparatus and method
AssigneeTerronics Development Corporation
InventorEduardo C. Escallon
Life of this patent
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AssigneeTerronics Development Corporation
InventorEduardo C. Escallon
Estimating the term…
An electrostatic powder coating apparatus comprising a powder reservoir, a gas flow injection chamber, a diffusion chamber and a coating chamber and method for coating a substrate or target objects. The injection chamber receives powder from the reservoir at a controlled rate. The powder particulates awe entrained by a gas flow within the injection chamber. The diffusion chamber receives the particulates from the injection chamber. The diffusion chamber deaccelerates the particulates and creates a particulate cloud. The coating chamber receives the particulate cloud. A housing encloses the coating chamber. The coating chamber is isolated from the ambient atmosphere. The coating chamber has a cloud inlet and a cloud outlet. The cloud flows through the coating chamber from the inlet to the outlet. One or more deflectors, within the chamber, define a passage and two or more pockets adjoining the substrate or target objects. The deflectors deflect the carrier gas from the pockets to the substrate or target objects. The substrate or target objects are transported within the chamber along the passage. Coating material within the passage is concentrated around the substrate or target objects. The coating chamber includes electrodes and voltage biasing means. The biasing means acts upon the substrate or target objects which are positioned within the passage. The particulates are electrostatically deposited upon the substrate or target objects within the passage.
A coating apparatus comprising a housing enclosing a coating chamber, said coating chamber being isolated from the ambient atmosphere, said coating chamber having a carrier gas inlet and a carrier gas outlet, means for providing carrier gas flow in said coating chamber from said carrier gas inlet to said carrier gas outlet, means for supplying coating material dispersed in said carrier gas, one or more deflectors disposed within said chamber, said deflectors defining a passage through which the articles to be coated are passed, said passage being in said coating chamber, said deflectors defining two or more pockets adjoining said passage, said deflectors being disposed to deflect said carrier gas from said pockets toward said passage, means for transporting articles to be coated within said coating chamber along said passage, and means for concentrating said coating material within said passage, said concentration means including one or more electrodes within said enclosure, said electrodes being spaced apart from each other, said electrodes adjoining said passage, said electrodes each defining a charging zone surrounding one of said electrodes, an electrical source connected to each of said electrodes, said electrical source imposing a voltage differential between said electrodes and the articles to b coated, said housing having partition wails dividing said coating chamber into an electrostatic chamber and a partition chamber, said partition chamber walls being sloped inwardly.
A method for applying coating material to a substrate comprising the steps of dispersing coating material into a carrier gas, isolating said carrier gas from the ambient atmosphere, transporting said substrate through said carrier gas, inducing movement of said carrier gas relative said substrate, deflecting said carrier gas spaced apart from said moving substrate in the general direction of said substrate, propelling coating material separated from said moving substrate towards said substrate by maintaining a voltage differential between said substrate and an electrode sufficient to form a corona discharge, contacting said substrate with a portion of said coating material, retaining on said substrate at least a portion of said coating material contacting said substrate, channeling said carrier gas through an area about said substrate, and settling said coating material, confining said coating material in close proximity to said substrate while allowing undeposited particulates to escape confinement into a particulate recovery zone.
A method for applying coating material to discrete objects comprising the steps of dispersing coating material into a carrier gas, isolating said carrier gas from the ambient atmosphere, transporting said objects through said carrier gas, inducing movement of said carrier gas relative to said objects, deflecting said carrier gas spaced apart from said moving objects in the general direction of said objects, propelling coating material separated from said moving objects towards said objects by maintaining a voltage differential between said objects and an electrode sufficient to form a corona discharge, contacting said objects with a portion of said coating material, retaining on said objects at least a portion of said coating material contacting said objects, channeling said carrier gas through an area about said objects and settling said coating material.
Dependencies are inferred from the claim text.