Impeller for boat

Abstract

This article is an impeller used in water jet propulsion systems for watercraft such as planing boats; while the outer surfaces of the impeller blades of ordinary impellers are mirror-finished, this article is characterized by the fact that the outer surfaces of the impeller blades have been shot-processed to create a convex random dot pattern; by creating a convex random dot pattern on the outer surfaces of the impeller blades in this way, water that has seeped in between the outer surfaces of the impeller blades and the inner surface of the impeller housing is repelled by the convex random dots, and the water pressure of the repelled water reduces the amount of air bubbles that seep in between the outer surfaces of the impeller blades and the inner surface of the impeller housing from the outside, thereby preventing the impeller from spinning freely; the portion indicated by the solid line is the part for which a design registration is sought as a partial design.

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