Abstract: A flow stabilizer is provided for reducing low frequency flow oscillations within and the resultant noise from the impeller of a transverse fan. Such oscillations and noise can arise in installations where the fan is located downstream of the heat exchanger in an air conditioning unit. The stabilizer is a vane located between the downstream face of the heat exchanger and the suction side of the impeller. The vane is positioned and oriented so as to reduce localized counter swirling flow that otherwise would cause oscillating blade stall within the impeller and associated noise.

Abstract: A rotatable louver assembly (20) for a fan discharge duct (14). The louver assembly has at least two louver slats (21, 22) that are fixed in spatial relationship with respect to each other. A first or upper louver slat (21) has a shape that conforms generally to the shape of a first or upper wall (41) of the discharge duct. The second or lower louver slat (22) has a shape that conforms generally to the shape of a second or lower wall (42) of the discharge duct. The louver assembly has at least two positions. In one position the first louver slat is generally aligned with and spaced from the upper wall to define a generally constant cross-section low loss passageway therebetween for directing air horizontally. In another position the second louver slat is generally aligned with the lower wall to define a generally constant cross-section low loss passageway therebetween for directing the air generally vertically.

Abstract: A transverse fan impeller (10) having blades (31) that extend longitudinally parallel to the rotational axis of the impeller. Each blade has an airfoil cross section, defined by a chord line (Ch) and a camber line (Ca), and is positioned in the impeller at a setting angle (.GAMMA.). The outermost edge (Eo) of each blade is located at a distance (Rmax) from the rotational axis (Ar, Ar'). The angular spacing (.SIGMA.) between blades in the fan is uniform. Among the blades of the impeller, the values of at least one of the parameters distance from outermost edge to rotational axis (Rmax), length of chord line (Ch), maximum deviation of camber line from chord line (Dmax) and setting angle of blades vary randomly from reference values of these parameters. The random parametric variations reduce the blade rate tonal noise produced by a fan having such an impeller as compared to a fan having an impeller with uniform blade parameters.

Abstract: A vortex wall (14) and impeller (30) assembly for a transverse or cross flow fan (10). The wall is intended to reduce blade rate tonal noise and is formed in a number of segments (15). The segments have noses with J shaped cross sections and are arranged so that the J tail (16) of one segment points in the opposite direction from the J tail of an adjacent segment. The spanwise widths (W), segment-to-impeller clearances (c) and setting angles (.theta.) vary randomly, within specified limits, among the segments.

Abstract: A low profile room air conditioner. The low profile is achieved in part by the arrangement of components in its outside section. The fan that moves air through the outside section is of the axial flow type mounted so that its axis of rotation is substantially perpendicular to the base of the enclosure and so that the fan draws air into the outside section through the top of the enclosure. Air discharges from the outside section through an air discharge on a side of the enclosure. Louvers at the air discharge direct the air exiting the enclosure away from the air inlet. A slinger directs droplets of condensate drained from the inside refrigerant-to-air heat exchanger into the air flowing through the outside section. The air carries the condensate on to the outside refrigerant-to-air heat exchanger where it evaporates. The air flow carries the resultant water vapor out of the outside section.

Abstract: A transverse fan impeller (30) having at least two modules (32). Each module is defined by an adjacent pair of partition disks (34) each perpendicularly centered on the rotational axis of the impeller. Blades (31) extend longitudinally between pairs of partition disks. The angular spacing of blades in a module is nonuniform but also not random, being determined by application of certain formulae disclosed. The angular blade spacing within each module of the impeller is the same, but the modules are angularly offset so that a blade in one module is offset from the corresponding blade in an adjacent module by a predetermined value. The module and blade configurations reduce both the blade rate tonal noise and overall radiated noise produced as compared to an impeller having uniformly spaced blades.