GB632809A - Improvements in or relating to ventilating fans - Google Patents

Abstract

632,809. Ventilators. WOODS OF COLCHESTER, Ltd., and BIRTWELL, W. G. Feb. 21, 1947, No. 5155. [Class 137] [Also in Group XXVI] The part of a duct carrying a ventilating fan 1 is movable from a position in which it aligns with the rest of the duct to one in which part of it or a member carried by it obturates the duct. In the form shown, the fan is mounted in a cylinder 4 in a wall opening 5 and normally aligns with an aperture 8 in a frame 9. The cylinder is supported from the frame and rotates about a vertical axis VA through 90 degrees to close the aperture by means of a disc 7, Fig. 2, and through 180 degrees to reverse the air flow. The upper cylinder pivot 15 includes a switch for the fan which is thereby automatically actuated in the two aligned positions and stopped in the obturating position. The fan motor may be of various types e.g. a two speed, shaded pole motor, three leads 19 being- connected thereto. The cylinder is rotated by a pin-and-slot mechanism from a cord 42 passing over a pulley 37. This mechanism may be of a modified Geneva type providing a 90 degrees rotation of the cylinder for a full rotation of the pulley. Alternatively, it may be of the form shown in Fig. 7 in which a plate 49 secured to the cylinder has slots in which pins 47, 48 on the pulley engage. A rotation of the pulley through 270 degrees will turn the platethrough 90 degrees stops 52 or 53 preventing further movement. A spring ball catch 54 indicates, when the position of Fig. 7 (the obturating position) is reached. The frame 9 is screwed to brackets 30 connected by bolts 31 to a louvred grid 32, Fig. 4, and either the frame or the grid may be on the inlet side. 'The parts may be of metal or plastics. An electric heater may be mounted in the duct. Other means are described for rotating the cylinder e.g. solenoids acting against a spring.