GB911111A - Improvements in centrifugal fan assemblies - Google Patents

Abstract

911,111. Centrifugal fans. BASS Ltd., JOHN. June 24, 1959 [July 22, 1958], No. 23441/58. Class 110 (1). A centrifugal fan comprises a casing in the form of an axially elongated duct, a partition dividing the duct longitudinally into an inlet side and an outlet side, and an impeller disposed within the duct to create flow of gas from the inlet to the outlet side of the duct by way of an aperture in the partition. The fan casing comprises a duct of rectangular cross-section and provided with flanges 17, 19 at the inlet end 13 and outlet end 15. A longitudinallyextending partition 21 comprises a central part 27 parallel with the top and bottom walls of the duct, and inclined end parts 29, 31 which provide a convergent inlet path and a divergent outlet path. The central part 27 has an arcuate edge 33 and an edge comprising an arcuate part 41 and a straight part 43. Plates 35 and 40 extend normal to the respective edges 33 and 41, 43 and between the top and bottom walls of the duct, but are apertured as shown for the flow of gas in the direction of the arrows, the central partition part 27 being provided with a circular aperture 51 for the same purpose. A baffle plate 45 has an initial part 47 substantially parallel with the side wall 9, and a final part 49 extending axially, to correspond to the outflow which is initially tangential to the volute 25 and then becomes substantially axial. The mounting plate 61 of the driving motor is bolted to the top wall of the duct, with the impeller depending through a hole in the top wall. The duct may be of polyvinyl chloride and the impeller may be of fibreglass.