Chromalox Big Red Book

Heating Cable

Impedance Heating System

• Uniform, Indirect Heating • Distances of up to Several Miles in Length • 1kW to Several MW of Power • Low Voltage Operation in the Process (less than 50V) • Temperatures to 2,000˚F (1,090˚C) • Watt Densities up to 190 W/in 2 (29.5 W/cm 2 ) • Hazardous Area Certifications Available

Shown Above: Heat Tracing and Freeze Protection

Shown Above: Heat Transfer and Process Liquifications

Description Impedance systems utilize the carrier pipe for the heating element and require no modifica- tions to the carrier pipe. A low AC voltage is supplied to the carrier pipe, with the result being that the carrier pipe becomes the heat- ing element. Impedance systems apply heat uniformly over the pipe surface eliminating "hot spots" which can damage sensitive mate- rials. These systems can be used at very high temperatures and can supply enough energy to heat the material as it is flowing. Impedance systems are much more efficient and safer than other tracing systems that can provide heat inputs up to 190 W/in 2 (29.5 W/cm 2 ) and temperatures up to 2,000˚F (1,090˚C). Several impedance systems can be connected together to heat longer pipelines. Applications • Raising or maintaining the temperature of a process stream, including the fluids that are thermally sensitive or highly viscous, or fluids that may solidfy in piping and need liquefied prior to pumping • Freeze Protection • Heating corrosive materials when direct im- mersion heating is not desired or practical Advantages • Accurate temperature control to +-1˚F - Available SCR power control can accurately monitor and control desired temperature • Uniform Heating - rather than having localized 'hot spots' for transfering energy,

Impedance heating allows for even, smooth heating along the entire circumference and length. • Simple Installation - As compared to electric heating elements, additional piping, valves, wiring, etc are not needed to ac- commodate Impedance heating. Impedance utilizes the pipe itself and minimizes the amount of eqipment needed. • Efficient, Compact area for heat transfer - Impedance heating allows higher watt densities to be used due to increased velocities and lower pressure drops. • Indirect Heating Contact - There are no concerns of corrosion on a heater sheath as the process is only heated by the pipe. • Can handle warm up or temperature main- tenance conditions - Impedance heating can be use for simply maintaining pipe tempera- tures or adding additional power to heat-up liquid flow. Impedance can also be used to liquify coagulated fluids when re-starting a system. • No routine maintainence needed - Imped- ance has no moving parts that require ser- vicing or that can cause costly shutdowns on operations. • No double jacketing - Steam or oil traced lines have additional hazards of frozen lines, or leaky connections. Impedance totally eliminates these concerns.

HEAT TRACING PRODUCTS

G-161

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