Abstract: A radial upblast exhaust apparatus includes a fan housing having a fan inlet to receive air to be exhausted and a fan outlet to expel air to be exhausted. An upper housing is positioned immediately above the fan housing. It includes a first wall section and a second wall section each shaped as a partial conical section being concaved toward each other. The upper housing forms an air outlet nozzle. A mechanism changes the outlet area of the outlet nozzle in order to provide a variable area outlet for the fan.

Abstract: An apparatus, system and method for improving air entrainment and sound attenuation of gases being discharged from one or more outlet portions of an exhausting device using an acoustic wind band. The acoustical wind band helps improve entrainment of ambient environmental air with the exhaust gases being discharged from the exhausting device resulting in a tight plume of high velocity flow which improves the effective stack height of the exhausting device. This is achieved by positioning the sections of the acoustical wind band in spaced relation thus forming passages that allow outside ambient environmental air to flow into the acoustical wind band to mix with and dilute the exhausting gas. The sections may also be positioned extending upward and inward at an angle to further enhance the entrainment of ambient environmental air with the flow of exhaust gas from the gas exhaust device.