HOUSINGS FOR AXIAL FLOW FANS

摘要

A cyclindrical housing (5) for an axial-flow fan, formed with an annular recess to provide an alternative path for air flow in the reverse direction when it occurs near the outer diameter of the fan blading (1). The recess contains vanes (20) whose curvature about the housing axes (12) changes progressively from the inlet end (4a) of the recess to the outlet end (4b) and which at least at the inlet end (4a) have a curvature about an axis (23) generally parallel to the housing axis, so that air which is travelling generally circumferentially as it enters the recess is initially deflected towards a radially-outward direction by encounter with the vanes. The recess may also contain a ring-shaped fairing (7) which physically separates the recess inlet (4a) from its outlet (4b) and which may serve to diminish turbulence in the air travelling through the recess.