Abstract: An induced flow fan assembly is provided with a pressure tap arrangement at the outlet for measuring the output flow of the assembly. The pressure sensing arrangement includes two rings of piezometers mounted to an outlet windband, one ring at the wider upstream end of the wind band and the outer at the narrower downstream end. Data regarding the pressure differential across the windband is acquired electronically and used to determine total output flow of inlet and entrained air streams. The fan assembly is suitable as an exhaust assembly for expelling contaminated air from a building.

Abstract: An exhaust system for expelling air from a building includes an outlet nozzle that improves entrainment of ambient air with the building exhaust air. The improved air entrainment results in increased exhaust air dilution and plume height to better disperse the exhaust air away from the building. The nozzle has an H-shaped outlet configuration with two lateral outlet sections joined by a central transverse outlet section. The nozzle has a pair of outer lateral walls, a pair of outer transverse walls, and a pair of sloped inner lateral walls that angle outwards from near an inlet end of the nozzle towards corresponding outer lateral walls. The nozzle can be part of the exhaust system at the outlet side of the exhaust fan within a windband that aids in entraining ambient air with the exhaust air exiting the nozzle.

Abstract: An exhaust fan assembly is provided for expelling contaminated air from a building. The assembly includes fan housing connected to the building via a duct. The fan housing contains a fan the draws air from the building through the duct. An extension is mounted to the outlet end of the fan housing, and has a cylindrical upper end connected to a nozzle. A windband is connected to the upper end of the nozzle, and provides an air entrainment path that allows ambient air to mix with the exhaust air prior to exiting through an exhaust fan assembly outlet.

Abstract: An exhaust fan assembly is provided for expelling contaminated air from a building. The assembly includes a plenum, a fan assembly attached to the plenum, and a windband mounted on top of the fan assembly. The fan assembly is constructed of cylindrical outer and inner walls which define a bearing chamber and surrounding annular space. A fan driven by a shaft extending downward from the bearing chamber draws exhaust air from the plenum and blows it up through the annular space to a nozzle at the top of the fan assembly.

Abstract: An exhaust assembly is provided for expelling contaminated air from a building. The assembly includes a plenum, a fan assembly attached to the plenum, and a windband mounted on top of the fan assembly. The fan assembly is constructed of cylindrical outer and inner walls which define a drive chamber and surrounding annular space. A fan driven by a motor whose shaft extends downward from the drive chamber draws exhaust air from the plenum and blows it up through the annular space to a nozzle at the top of the fan assembly. The motor is pivotally mounted inside the assembly to provide access to the motor components when it is desired to perform inspection and maintenance.