Abstract: A safety valve responding to overheating conditions of the surrounding atmosphere, more specifically a combustion gas inlet valve that closes when a fire declares. The valve uses a shape-memory element for detection and command. For the latter function it must be inside the valve, at the expense of sufficiently rapid detection of external temperature. This problem is solved by using a shape-memory element that is in close contact with the valve housing, e.g. countersunk in a groove in the internal wall of the valve housing, for facilitating conduction heat transfer.

Abstract: A warning device for indicating a predetermined temperature level of a solid object includes inner and outer concentric telescoping tubes having outer surfaces of different and contrasting appearances; a heat-conducting device for fixing one of the tubes to the solid object; a temperature-responsive spring element disposed within and abutting each of the tubes, the spring element being made of a material having shape memory properties such that upon an increase in temperature it expands and causes outward telescopic movement of one tube relative to the other tube to thereby expose the outer surface of the inner tube to view.