THERMAL SWITCH Russian patent published in 2000 - IPC

FIELD: electrical engineering. SUBSTANCE: thermal switch designed for automatic control, monitoring, check-up of various thermal processes by ON/OFF switching of electric circuit in case of deviation of monitored medium temperature from desired value, such as for fire alarms, has cylindrical case accommodating contact system of movable and fixed contact strips and heat-sensing power element. The latter is a band made of material with shape memory effect inserted between case and movable contact strip. The latter is overhanging from butt-end insulating wall of case. Novelty is that contact strips are arranged along center line of cylindrical case so that contacts open in crosswise direction relative to axis. Heat-sensing power element is, essentially, part of turn abutting against inner cylindrical surface of case with its one end fixed in position and other one loosely mounted for actuating movable contact member. Thermal switch can be implemented in two modifications with respect to versions of their mechanical design. First modification has cylindrical case made in the form of tube section and contact strips have power leads on opposite sides. In second modification, switch case is made in the form of sleeve and both contact strips have their leads brought out from one side of case. Second modification is more useful for devices where tightness of switch is essential. Heat-sensing element may be placed either in front of making point of contact strips, or on side of movable strip joint or behind making point. EFFECT: reduced lag time, facilitated manufacture. 6 cl, 8 dwg