Patent GB-580232-A (GB)
Title: Improvements in and relating to temperature controlling devices
IPC: B64D15/02
Filed: 1944-06-23
Abstract: 580,232. Temperature controlling devices; turbines. BRITISH THOMSON-HOUSTON CO., Ltd. June 23, 1944, No. 12008. Convention date, June 25, 1943. [Class 110 (iii)] [Also in Groups XXIX and XXXIII] A temperature-responsive device capable of operating a control is provided by a turbine the blades of which are themselves responsive to temperature variations, being, for example, made of a bi-metallic sheet, or are angularly adjusted by a temperature responsive device. The device is applied to the maintenance of a constant temperature in a stream of fluid and this stream, or a sample portion of it, is used as the driving fluid for the turbine. In the normal condition, corresponding to the desired temperature, the turbine blades are in a neutral or ineffective form or position and flow of fluid through the turbine does not cause it to rotate. Change of temperature causes the blades to curve, or be angularly adjusted, from the neutral position and the flow of fluid causes rotation of the turbine, in one'direction for falling temperature and in the opposite direction for rising temperature. Rotation of the turbine may be used to operate valves by which the rate of flow of the fluid-through a heater is varied so as to maintain the temperature of the fluid constant, or, it may operate a reversing switch for an electric motor which operates the valves or controls the heating means. In one form, Figs 3 and 5, the turbine is of the outward radial flow type and the blades 30, which are made of bi-metallic strip, are radially disposed in their neutral condition. The air stream is introduced axially and is guided by plates 48, 49 to the spaces defined by the blades and the turbine casing walls 50, 55. As a zeroising device, the portions 49 of the guide plates may be twisted a little by the angular adjustment of a ring 51 to which the plates are connected by pins 52. The main stream of fluid passes through the duct 19 and a sample portion is diverted by a diametrical scoop 44 to the inlet guides 48. After passing through the turbine, this portion is received in a chamber 57 and is returned to the main'stream through a duct 59. The main stream is controlled by two shutters, one on either side of the scoop, and these shutters are moved by the turbine through gearing 62 and shifts 61, 26. These shafts are coupled by a device which acts positively, in opening the shutters but through a coiled spring in closing them. This permits an independent opening of the shutters. The turbine motor drives its shaft 31 through a friction clutch 32. In another form, an axial flow turbine is used, the whole of the main stream passes through the turbine and the blades which are of bi-metallic strip are secured to the rotor at their up-stream ends. In a third form, the blades of an axial flow turbine are carried by radially disposed spindles having crank arms at their inner ends which engage with a sleeve carried by the free end of a helix made of bi-metallic strip. The main stream flows through and about the helix and passes over the turbine blades. Fig. 15 shows an over-riding device by which the control can be transferred from the temperature-responsive device 119 to a hand-control 122. The lever 129 of the device 119 is linked to a plate 127 which is pivoted at its lower end to a fixed part 126. The lever 133 on the shaft 121, by which the shutters or other control are operated, carries a link 132 and a roller 131. The other end of the link lies in a notch 130 in the plate 127 when the device 119 is operative. The roller end of the link is carried by a rod 135 pivoted to a slide block 136 and when this is moved up by means of the hand-lever 122 the connection between levers 129 and 133 is broken. Upward movement brings the roller into contact with a fixed surface 139 which causes the rod 135 to swing to the right and the rod 132 to turn the shaft 121 to, say, the closed shutter position. Further upward movement causes the roller to enter a cam-groove 140 and the amount of opening of the shutters is determined by the position of the roller 313 in this slot. An aeroplane is shown with two systems of heating ducts. One system includes the wing de-icing ducts and the air is heated in an exchanger by the engine exhaust gases. The other system includes a petrol air heater. Both systems include the device for controlling the temperature.