| 摘要 |
664,011. Screw fans. DAVIDSON & CO., Ltd., and MACFARLANE, D. Sept. 19,1949, No. 24053/49. Class 110(i) In a ventilating unit comprising a fan unit pivotally mounted on trunnions within a casing so that it can be turned relative to the casing. through an angle of 180 degrees about an axis transverse to the axis of the fan unit and casing, the casing is provided with one or more doors to allow the fan unit to be turned. The fan unit, Figs. 1 and 2, comprising a motor 10 and impeller 12, is mounted on trunnions 24 pivoted in bearings 25. The unit is secured in either of its two positions by a locating ring 27 which is fixed to one trunnion 24 and carries a bolt which engages one of two diametrically opposed sockets 29. Current is supplied to the motor cable 33 by way of slip rings 32 contacted by stationary brushes. Alternatively, a flexible cable is used. The fan casing 14, which has flanged ends 15 for bolting to the ducts of a ventilating system, has hinged doors 19 which are opened as shown when a reversal is to be made. Alternatively, the doors may slide longitudinally. In a modified construction (not shown), the trunnions 24 are located nearer to the tip of the motor fairing 11, so that the latter swings entirely within the casing 14 when a reversal is being made, so that only one door 19 is required. Fig. 5 shows an embodiment in which two contra-rotating impellers 39, 40 are driven by separate motors 36, 37 mounted in a common carcase 38. A bearing bracket 41 may be integral with or attached to the trunnions 24 and/or the carcase 38. |
