Patent GB-760732-A (GB)
Title: Improvements in or relating to ventilating apparatus
IPC: F24F7/06
Filed: 1954-03-03
Abstract: 760,732. Axial-flow and centrifugal fans; air turbines. ENFIELD CABLES, Ltd., and CHAPLIN, S. Feb. 17, 1955 [March 3, 1954], No. 6279/54. Classes 110 (1) and 110(3). In a fan for enclosed space ventilation, of the type including a rotor having at least one blade carried on a hub, and a duct within the blade communicating at the blade root with an airsupply or air-exhaust duct extending through the hub, so that when the fan is in operation, the external surface of the blade imparts circulation to the air in the space to be ventilated, while at the same time air is introduced into the space, or removed therefrom, through an aperture or apertures in the blade, each aperture is formed exclusively in the region of the blade tip. An electrically-driven axial-flow fan, situated in the cellar of a building, supplies air through a cleaner and a humidifier to a main duct which communicates with a branch duct 32, Fig. 2, at each floor of the building. A heater or cooler may be provided ahead of the humidifier. Each duct 32 supplies air to ceiling fans, each fan comprising a suspension tube 37 universally jointed at 36 to a junction-box 33. The fan rotor comprises a hub 38 journalled on the tube 37, and hollow blades 39, 40 through which the air flows from the tube 37. Guide vanes 44, 45 at the discharge openings 42, 43 deflect the air into the tangential direction, causing rotation of the fan rotor in the manner of a Barker's Mill. Fresh air is thus discharged into the room, while circulation of air is effected by the fan blades 39, 40. Air may be drawn into the fan blades instead of being discharged from them. The fan may have a single blade or more than two blades. The supply of air to the fans may be controlled by valves which are operated manually or by electromagnets controlled by remote control switches or thermostats. If a heater is provided, the fans are preferably fitted with locking-means which prevent them from rotating during supply of hot air. In a modification, the fan hub is enlarged to house a turbine wheel which assists the rotation of the fan. In the embodiment shown in Fig. 3, the air flow through tubes 72, 73 each having a discharge aperture 74. The fan blades 75, 76 are carried by tubes 77, 78 journalled on the tubes 72, 73. The aerodynamic forces on the blades tend to rotate them against the action of torsion springs 83, 84 to a position of increased pitch. The fan shown in Fig. 6 is rotated by an electric motor 111. The rotatable motor casing is fixed to the fan hub 109, while the stationary motor shaft 112, through which the supply cable 114 runs, is suspended from a ball mounting 113. The air supply tube 119 is connected to the supply duct 115 through a ball-andsocket joint 117, 118 concentric with the ball mounting 113. The discharge apertures at the blade tips may face radially outwards. The rotation of the blades 108 induces an outward flow of air through their hollow interiors by centrifugal action, so that the main fan feeding the supply duct 115 may be omitted. The fans may be constructed as table fans instead of ceiling fans and each provided with a flexible supply tube having a bayonet connector for insertion into a bayonet outlet provided in a supply duct which runs along the skirting board of the room.