Abstract: A shaft seal for an exhaust fan. The seal limits leakage from within an exhaust fan housing around an exhaust fan drive shaft that extends between a rotational power source exterior to the exhaust fan housing and a position within the exhaust fan housing. The seal comprises a plenum generally positioned about the exhaust fan drive shaft at the point where the shaft extends into the fan housing; an auxiliary blower comprising a housing, an internal blade driven by an auxiliary blower drive shaft, and an auxiliary blower drive to rotate the drive shaft where the auxiliary blower drive is operatively associated with the rotational power source such that operation of the rotational power sources causes a rotation of the exhaust fan drive shaft and the auxiliary blower drive shaft; and a duct fluidly connecting the auxiliary blower housing to the plenum.

Abstract: A windband for an exhaust fan system. The windband comprises an elongate housing receivable about a exit nozzle of the exhaust fan system, an air inducer formed from a perforated material and positioned adjacent the bottom portion of the elongate housing, and a discharge sleeve positioned adjacent and secured to the top portion of the elongate housing. The discharge sleeve is formed from a perforated material and forms a passageway through which gas from the nozzle and induced ambient air passing through the elongate housing are discharged. The perforated air inducer and discharge sleeve together assist in the minimization of a pressure differential between an upwind side of the windband and a downwind side of the windband when the windband is subjected to wind striking the windband at an angle.

Abstract: An exhaust gas discharging apparatus for connection to an exhaust gas fan including an exhaust gas nozzle comprising a duct device forming at least one exhaust passage that extends between first and second open ends. The duct device has at least one exterior duct wall forming at least two longitudinally extending bent wall portions that are distributed evenly about the periphery of the duct device with each bent wall portion sloping towards the longitudinal axis in the region of the second end. An annular cap or wind band is connected to the duct device and is disposed about and spaced apart from the second end of the duct device. The cap has a cap inlet located below the second end and outside the duct device and a cap outlet located outwardly from the second end in the longitudinal direction. Vertically extending wind deflecting panels are mounted on the duct device and extend horizontally outwardly and these panels extend vertically below the cap.

Abstract: An exhaust gas nozzle comprising a duct member forming a single exhaust passage and defining an open first end, an open second end, and a centrally-disposed longitudinal axis extending between the first end and the second end. The duct member includes at least a pair of bent wall portions spaced-apart from one another, these bent wall portions extending from the first end to the second end and gradually and increasingly pinching the passage from the first end to the second end. An annular, open-ended windband is connected to the duct member and disposed about the exterior of and in spaced, coaxial relation to the second end. A windband inlet is located below and in the region of the second end and outside the duct member.

Abstract: A combined propulsion and lift unit for an air-cushion vehicle is provided comprising an elongate shaft mounted for rotation about its central longitudinal axis, bearings for rotatably supporting the shaft, an axial wheel with two or more blades mounted on the shaft for rotation therewith, a first housing extending peripherally about the shaft, the housing provided with an air inlet and an air outlet, a drive device connected to the shaft for rotating same at a selected speed, a centrifugal fan wheel mounted on the shaft for rotation therewith, the fan wheel provided with an air inlet, the fan wheel located inside the first housing, and a second housing extending about the perimeter of the axial wheel and the first housing, the second housing having a larger diameter than the first housing thereby defining an air passageway therebetween, the second housing provided with an air inlet and an air outlet.

Abstract: A centrifugal fan including a fan wheel and a driveshaft for rotating the wheel in a housing. The fan wheel has an axial center and outer edge portions around the radially outermost extremities. The housing is formed of right and left unitary housing halves of the same size and shape. The housing halves each form a sidewall of the housing and a portion of a circumferential wall of the housing. The housing halves are joined directly to one another to form the housing. The housing has a suction inlet in one of the right and left housing halves at the axial center of the wheel and a fan outlet formed by the housing. The outlet has a center line that is located generally on a radius extending from the axial center of the fan wheel. A chamber for the fan wheel is formed in the housing. A baffle is rigidly connected to the housing and is located in the housing adjacent the side of the fan outlet towards which the fan wheel rotates.