The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 12, 1996
Filed:
Apr. 20, 1995
George P Beason, Jr, Arab, AL (US);
Timothy N McKechnie, Huntsville, AL (US);
Christopher A Power, Guntersville, AL (US);
Plasma Processes, Huntsville, AL (US);
Abstract
An improved nozzle for reducing overspray in high temperature supersonic plasma spray devices comprises a body defining an internal passageway having an upstream end and a downstream end through which a selected plasma gas is directed. The nozzle passageway has a generally converging/diverging Laval shape with its upstream end converging to a throat section and its downstream end diverging from the throat section. The upstream end of the passageway is configured to accommodate a high current cathode for producing an electrical arc in the passageway to heat and ionize the gas flow to plasma form as it moves along the passageway. The downstream end of the nozzle is uniquely configured through the methodology of this invention to have a contoured bell-shape that diverges from the throat to the exit of the nozzle. Coating material in powder form is injected into the plasma flow in the region of the bell-shaped downstream end of the nozzle and the powder particles become entrained in the flow. The unique bell shape of the nozzle downstream end produces a plasma spray that is ideally expanded at the nozzle exit and thus virtually free of shock phenomena, and that is highly collimated so as to exhibit significantly reduced fanning and diffusion between the nozzle and the target. The overall result is a significant reduction in the amount of material escaping from the plasma stream in the form of overspray and a corresponding improvement in the cost of the coating operation and in the quality and integrity of the coating itself.