Constant Wattage Heat Tracing Cable

Constant wattage heat tracing cable means that the output power of the electric heating cable remains basically constant after power-on, and will not be affected by factors such as external temperature, insulation materials, and heating objects.
There is a certain difference in power output between constant wattage heat tracing cables and self-regulating heating cables. Since constant wattage heating cables will not adjust power output with temperature changes, it is often necessary to add additional control components, such as controllers, Temperature limiter, etc. to keep the constant wattage heat tracing cable in normal operation, especially for use in some special environments, such as explosion-proof areas with temperature group requirements.

According to the structure type, the constant wattage heat tracing cables can be roughly divided into parallel constant wattage heat tracing cables and series constant wattage heat tracing cables. There are two special types of electric tracing cables, mineral insulated electric tracing cables that meet high temperature and high power requirements, and skin effect electric tracing cables that are suitable for ultra-long pipelines.

Parallel constant wattage electric heat tracing cable, the heating resistance wire is connected in parallel, and when it works, it relies on the resistance wire to generate heat to transfer heat to the pipeline; two parallel nickel-plated copper strands are wrapped in a fluoropolymer insulating layer , as the power bus wire, and the nickel-chromium alloy heating wire is wound outside the inner insulating layer, and the resistance wire is welded at a fixed distance to form a continuous parallel resistance. When the power bus is energized, each parallel resistance will generate heat. That is to form a continuous heating electric heating cable, which can be cut arbitrarily within a certain length range.

Series constant wattage heat tracing cable, the heating resistance wire is connected in series, and when it works, it relies on the resistance wire to generate heat to transfer heat to the pipeline or equipment. The core wire with a certain internal resistance will generate Joule heat when the current passes through it, and the heat is proportional to the square of the current, the core wire resistance and the passing time. Therefore, with the continuation of the power-on time, the series heating cable continuously emits heat, forming a continuous and uniform heating cable. Series constant wattage heat tracing cables have the same core wire current and equal resistance, so the whole electric heating cable heats up evenly from the beginning to the end, and its output power is constant and basically not affected by the ambient temperature and pipeline temperature.

On the whole, the parallel constant power electric heating cable is mainly used in petroleum, chemical, electric power, metallurgy and other pipeline systems, storage tanks, valves, heat tracing of pump bodies, antifreeze or process temperature maintenance of instrument pipelines. It is suitable for heat tracing and heat preservation of short-distance and large-diameter pipelines. Series constant power electric heating cables are suitable for long-distance pipelines where the circuit length exceeds the upper limit of parallel constant power electric heating cables and there are relatively few power supply points.

Compared with self-regulating heating cables, constant wattage heat tracing cables have the following advantages:
1）Stable power output, more suitable for process temperature maintenance that requires stable output power
2）Series electric heating cables are suitable for heating objects with long distances and relatively few power supply points
3）Suitable for wide range voltage applications