US 5,881,685 A · Fan shroud with integral air supply

Abstract

A shroud for an axial blade fan provides a circumferential, axially directed flow of air between the fan blade tips and the shroud to improve fan efficiency. The shroud preferably includes a smaller, centrally disposed fan which is driven by an auxiliary motor, a circumferentially extending generally toroidal plenum, a plurality of hollow spokes providing fluid communication between the fan and the plenum, a circular throat which directs air toward the annulus between the shroud and the fan blade tips and a throat adjacent, circumferential Coanda surface which controls and guides air exiting the throat. Air is provided to the shroud plenum at a pressure of between about 2 and 10 inches water gauge (4 to 20 Torr). The narrowest region of the circular throat has a width of between about 1 mm to 5 mm. Adjustment of the air pressure and throat dimension allows accurate control of the velocity profile of the air flow through the annulus.

Claims20

Dependent claims

A shroud assembly for improving the operating efficiency of a fan comprising, in combination,

a shroud adapted for disposition about a first fan, said shroud defining a plenum and having a substantially circular opening for receiving such fan, a substantially continuous throat extending around said opening and communicating with said shroud plenum,
a fan housing,
a second fan disposed in said fan housing, and
a plurality of air passages extending between said fan housing and said shroud plenum.

1 more element

Dependencies are inferred from the claim text.

Fan shroud with integral air supply

Life of this patent

Fan shroud with integral air supply

Life of this patent

Abstract

Claims20