SE305711B - - Google Patents

Abstract

988,854. Centrifugal fans. JUNKER & RUH A.G. April 14, 1961 [June 2, 1960], No. 13437/61. Heading F1C. [Also in Division H2] An air current is produced by leading the air to an impulse-exchanging rotor in the form of a fibrous unit which separates intake and pressure chambers, the air being deflected, on flowing radially through the unit, in such a manner that the mechanical energy of rotation of the unit is connected into flow energy of the air. Fig. 3 shows a fan in which the impeller comprises a ring 32 of felt or other fibrous material in which the fibres are preferably arranged along the peripheral direction whereby the air passing through the fibrous material is acted on by frictional forces only. In passing through the volute 33, the air cools the driving motor 36. A rotary deflector 34 may be provided to direct the air flow around the motor. In addition, a stationary deflector (not shown) extends from the cut-off of the volute towards the motor. The air is filtered by the fibrous material, which may be a plastics material so as to receive an electrostatic charge which enhances the filtering. The elimination of fan blades reduces noise, and the flow is stable at all rates of flow. The impeller may be provided with a humidifying device, the large area of contact between the air and the fibrous material allowing the air to be readily humidified or evaporatively cooled. The fibrous material may be in the form of a disc instead of a ring. In the embodiment shown in Fig. 5, the fibrous disc 63 is carried by an impeller including a conical portion 63a serving as the rotating inner wall of an annular diffuser through which the air is discharged in an axial direction. Some of the air returns from the diffuser in the direction of the arrows 72 to cool the driving motor 71, re-entering the impeller through by-pass openings 69. Heating filaments or condenser coils may be introduced into the exhaust cross-section without producing noise by interference with the air flow. In a further embodiment, Fig. 8, the impeller comprises three rings 107 of fibrous material, resting loosely within a reticulated container 102 and readily removable for cleaning purposes. The container 102 is carried by the external rotor 101 of a driving motor, the stationary shaft 103 of the motor being supported by springs 104 and rubber bushes 105.