GB625272A - - Google Patents

Abstract

625,272. Temperature-responsive actuating elements. BRITISH THOMSON-HOUSTON CO., Ltd. Aug. 6, 1946, No. 23299. Convention date, Aug. 6, 1945. [Class 64(ii)] Relates to control actuating elements, which are responsive to the flow of an electric current and to the temperature of an associating medium. According to the invention a control actuating element comprises an electrical resistance in the form of a hollow tube connected to a flexible bellows having a fluid filling extending into the tube. Mounted on an electrically insulating base 1 is an angle support 7 carrying a flexible bellows 3 filled with an expansible fluid 4, which may be trichloroethylene. One end of a hollow tube 2, partly filled with the fluid 4, enters an electricallyconducting member 9 extending from the bellows 3. The tube 2 of electrically resistant material is connected to electric current terminals 5, 6. Means for adjustably loading the bellows comprises a flat spring 12 slipped over the end of the bellows 3, adjustable screws 15 bearing on the ends of the spring 12. The thermal control device is shown applied to an electric switch of the type described in Specification 564,681, [Group XXXVII]. The switch 16 having terminals 17, for connection to the electric circuit to be controlled, is so placed that expansion of the fluid 4 in the bellows 3 moves an actuating part 18 of the switch. The passage of an electric current through the tube 2 with consequent heating of the tube 2 and its contents, causes the fluid 4 to expand. Initial adjustment of the switch 16 and the temperature responsive control means can be made by adjusting screws 8 in slots 19 in the angle support.