Abstract: A continuous temperature sensing cable formed of a polymer containing conductive and semi-conductive fillers such as polyethylene with carbon black, powdered metals and metal oxides. The composition is extruded over a pair of elongated substantially parallel conductors which are spaced apart along the longitudinal length of the cable. The conductors are single-endedly connected to a control/alarm device for monitoring the continuous length of the temperature sensing cable. A critical voltage is applied single-endedly to the conductors and serially connected to an audible alarm to detect tunneling conduction when operated at a temperature near the melt temperature of the composition whereat the composition exhibits a negative temperature coefficient (NTC).

Abstract: A continuous temperature sensing cable formed of a polymer containing conductive and semi-conductive fillers such as polyethylene with carbon black, powdered metals and metal oxides controlled within the range of from about eight percent (8%) to about fifteen percent (15%). The composition is extruded with a pair of elongated substantially parallel conductors which are spaced apart along the longitudinal length of the cable. The conductors are single endedly connected to a control/alarm device for monitoring the continuous length of the temperature sensing cable. The control/alarm device may be a time domain reflectometer TDR for accurate determination of localized discontinuities caused by high temperatures along the length of the temperature sensing cable. Alternatively, a critical voltage may be applied single-endedly to the conductors and serially connected to an audible alarm to detect tunneling conduction when operated at a temperature near the melt temperature of the composition.

Abstract: A method for producing a self-regulating heating cable is provided. A first conductive constituent is cryogenically cooled to a temperature at least as low as its glass transition temperature, and ground into first conductive pellets. A second conductive constituent is cryogenically cooled to a temperature at least as low as its glass transition temperature and ground into second conductive pellets. The first and second conductive pellets are combined to obtain a mixture which is extruded over a pair of conductive wires to form a cable.