GB460781A - Improvements in or relating to fans, rotors, and the like - Google Patents

Abstract

460,781. Screw fans and windmills. SPOONER, W. W. Aug. 6, 1935, No. 22112. [Classes 110 (i) and 110 (iii)] A screw fan, propeller, or windmill comprises two or more coaxial rings of blades, or rotors, of different diameter, each independently mounted for rotation at speeds inversely proportioned to the diameter so as to preserve a uniform airflow without the necessity for excessive angularity of blade in the outermost rotor. The blades are mounted in separate rotors X, Y, Z, driven at the same peripheral speed by belts or friction pulleys acting on the outer sheaths, or the rotors may be interconnected by epicyclic gearing. Alternatively, the front rotor only may be positively driven, the successive rotors being driven by the slip stream from the preceding rotor, for which purpose the blades of the successive rotors radially overlap as shown, or each successive rotor may have a separate ring of blades to receive the slip stream from the preceding rotor. For use as a windmill the several rotors may drive a common shaft through gears of different ratio. A single rotor with concentric rings of blades of increasing angle is described, but forms no part of the invention, and according to the Provisional Specification stationary blades may be provided in series with the rotor to reduce whirling motion of the air.