Radial-flow impeller with radially free base ring

摘要

The impeller has a basic rim (12) provided with blades (15) protruding on a surface (12f) of the basic rim. An annular hub (13) is adapted to be coupled to the rim and to a rotary shaft (3). An annular plate (14) and the rim are configured to interact with each other. The rim comprises a circular key (17) on its inner perimeter for interacting with a notch (18) made in the hub and another notch (19) made in the plate. The notches are placed opposite to each other such that the circular key is held in the notches when the hub, the plate and the rim are assembled.