ROTOR, MEANS AND METHOD OF MAKING THE SAME BY MOULDING

摘要

A pump impeller comprises a hub surrounded by a web which is a surface of revolution about, and whose imaginary projection intersects, the hub axis, the web carrying helico- centrifugal vanes with both faces of each vane parallel and formed as acute helicoids about the hub axis. The impeller is made by constructing a plastic pattern having vanes 12, using the pattern to form a sand mould, withdrawing the pattern from the sand with a helical movement and then filling the mould cavities with liquid metal.