Since its introduction in 1971, the heated semiconductor core has behaved as a variable temperature resistor that reverses the trend of high/low heating temperature, as the heat trace power varies with the temperature of various places on the electric heat trace. Self-limiting electric heat traces have become the most common type of electric heat trace in the world today. They can be widely used in the transportation of liquid objects in pipelines and tank antifreeze insulation, maintenance of process temperature, heating of roads, ramps, pedestrian crossings, eaves and floors. Between the two conductive cores of the self-limiting electric trace, a semiconductor polymer material that plays a heating role, and its outer part is composed of a polymer inner sheath, an alloy shielding mesh and a polymer outer sheath. When a current passes, the cable resistance rises as the temperature of the electric trace increases. As a result, the output power of the electric cable decreases as its temperature increases. Since the heat trace power varies with the temperature everywhere on the electric trace, the heated semiconductor core appears as a variable temperature resistance that is the opposite of the high/low heating temperature trend. Self-limiting electric heat traces do not overheat even when overlapping. Without special design, the self-limiting electric trace can cut its working length on site to accurately correspond to the actual laying length of the pipe, without special tools, and is extremely easy to install.
