GB346360A - Improvements relating to temperature indicators - Google Patents

Abstract

346,360. Thermometers. SLOUGH, F. M., 602, B. F. Keith Building, Cleveland, Ohio, U.S.A. Nov. 30, 1929, No. 36801. Convention date, Nov. 30, 1928. [Class 97 (iii).] In apparatus for the remote indication of temperature, comprising a bimetallic element subjected to the temperature to be measured and arranged to close contacts when the temperature rises so as to complete a circuit including means for operating an indicator, one of the contacts is actuated by a second bimetallic element which is provided with a heating element included in the electrical circuit, the second bimetallic element being adapted on being heated to move its contact to break the circuit. The apparatus is particularly intended for measuring the temperature of the cooling water of an internal-combustion engine. In the form shown the bimetallic strip 26 is secured to a heat-conducting plug 17 projecting into the water jacket 3 and carries a contact 33 on a screw 36. The contact co-operates with a contact 32 carried by a bimetallic strip 13 on which is mounted a heating coil 16 the circuit of which is completed by closure of the contacts. The circuit also includes an electromagnet 12 co-operating with an armature 15 on the strip 13, and a heating coil 41 associated with a bimetallic strip 46 which actuates the pointer 42 of the indicator. Another bimetallic strip 45 is interposed between the strip 46 and the pointer, to compensate the indications for variations of atmospheric temperature. As the temperature of the strip 13 is raised by the coil 16 the contact 32 tends to move away from the contact 33 until the circuit is ultimately broken, the interruption of the circuit of the electromagnet 12 causing the contacts to separate with a snap action. Further heating of the strip 26 causes the contacts to close again, and so on. The position of the pointer 42 for a given temperature can be regulated by adjusting the screw 36.