Resistive sensor for position detection of manifold failures

A sensor for determining the location of overtemperature conditions, the sensor comprising, in combination:

• an elongate coaxial sensor cable having a conductive metallic sheath and a conductive metallic core both made of metals capable of withstanding, without failure, the heat of the overtemperature condition, the core being positioned within and coaxial with the sheath, the elongate cable being sufficiently flexible to be routed in proximity to a system to be monitored,
• a eutectic salt insulator interposed between the core and sheath for preventing contact therebetween, the eutectic salt having a melting point related to a design temperature at which the overtemperature condition is to be detected,
• at least one of the core or sheath having a predetermined and measurable resistance per unit length sufficiently high to allow differential drive and sensing from the respective cable ends to isolate the position of a core-to-sheath short,
• the eutectic salt insulator being constructed such that when heated to the design temperature at a point of overtemperature condition it provides a core-to-sheath short at said position rendering the core-to=sheath resistance determined by differential driving and sensing the cable from its respective ends an indication of the position of the short along the cable.