Extreme temperature drops don't always lead to problems. When the process requires precision, a slight change can cause a product to thicken, delay flow, or leave a valve "sticky." In order to keep your operation within its safe temperature range, a heat trace system replenishes the heat that pipes, tanks, and fittings lose to the surrounding air.
The functions of a heat trace system
A pipe leaks heat when it runs hotter than the surrounding air. Although it slows it down, insulation cannot reverse that loss. In order to provide either freeze prevention or temperature maintenance, electrical tracing restores the lost heat.
That second objective frequently makes the news in the oil and gas industry. Maintaining hydrocarbons and chemicals above critical temperatures to prevent wax or hydrates from choking the line and causing downtime is known as flow assurance, and it goes beyond freezing.
Three Cable Families that you will see repeatedly
The majority of selection arguments center on the cable's behavior in various scenarios.
1) Self-regulating cable, sometimes referred to as "tape."
The output of this wire is temperature-dependent. The output increases as the pipe cools and the core becomes more conductive; the output decreases as the pipe warms.
2) A cable with a constant voltage
Constant wattage is typical if maintaining viscosity or a steady process setpoint—for instance—is your top objective when it comes to heat during the run. It can provide consistent output over its length because it is constructed with recurring heating "zones."
3) A cable with constant power (series resistance)
When energized at its operational voltage, this resistive heating element generates heat. It is usually employed when the design heat loss is well understood and the output must be predictable over a specified period of time.
A Useful Checklist
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Put the goal in writing. "Temperature maintenance" and "freeze protection" are two different designs. They have varying cable options, control setpoints, and drive watt densities.
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Not the drawing, but the actual pipe's design. Heavy fittings, valves, and flanges lose more heat and frequently require additional tracing coverage to make up for it.
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Select the level of control that corresponds to the risk. Many freeze-protection tasks can be completed with just an on/off thermostat. Microprocessor-based control/monitoring can input data into plant systems and regulate more precisely for tighter stability and improved visibility.
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Consider insulation to be a component of the circuit. Effective insulation lowers running costs, increases stability, and lowers the amount of power used. For safety and maintenance clarity, add vapor barriers where moisture intrusion is expected to occur and finish with clear tracing labels.
The Bottom Line
Because lines don't freeze, fluids don't stall, and setpoints don't shift, the best heat trace system is the one you hardly notice. When you're prepared to create or improve tracing for difficult industrial duty, collaborate with a supplier like Tempsens that can assist with selection, controls, and commissioning from start to finish.
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