In heat transfer oil circulation systems, tubular electric heaters operate at high temperatures for extended periods, and surface coking or insulation degradation are common issues. For such scenarios, the following Q&A is provided for reference by technical engineers.
A: Focus on checking whether the terminal connections are loose or oxidized, whether there is carbon buildup or oil sludge attached to the surface of the heating tubes, and whether there is leakage at the flange or threaded connections. It is recommended to record the insulation resistance once a month. If the resistance value drops significantly from the initial value, the cause should be investigated.
A: Avoid frequent starts and stops to reduce the stress impact of thermal cycling on the tube wall; control the degradation rate of the heat transfer oil and regularly test the acid value and residual carbon; ensure the liquid level is always above the heating zone to prevent dry burning. After shutdown, it is recommended to cut off the power first and wait until the temperature drops to a safe range before stopping the circulation pump.
A: Confirm the medium type, operating temperature, power and voltage level; verify the installation interface dimensions, insertion depth, and wiring method; refer to NB/T 10309-2019 for relevant requirements on metal tubular heating elements. If corrosive media are present in the working conditions, the corresponding sheath material should be selected.
A: First cut off the power and measure the insulation resistance to rule out moisture or breakdown; then measure the resistance of individual tubes to determine if there is an open circuit. Slow heating may be related to low voltage, failure of some heating tubes, or abnormal oil flow rate, and should be investigated item by item.
