In chemical storage tank areas, operators need to regularly inspect the heat tracing system to maintain the medium temperature and prevent solidification. As a common electrical heat tracing element, the installation and maintenance of stainless steel explosion-proof heating rods directly affect system stability. The following maintenance points are listed from the perspective of a technical engineer.
Before installation, verify whether the rated voltage, power, and explosion-proof rating of the heating rod are consistent with the design documents. Check the sealing surface of the wiring cavity for scratches and whether the fastening bolts are complete. For heating rods stored for a long time, measure the cold insulation resistance with a 500V megohmmeter; the resistance should not be less than 20MΩ. If it is lower than this value, drying treatment is required.
During operation, regularly record the working current of the heating rod, and the deviation from the rated current should preferably be controlled within ±10%. An abnormal increase in current may indicate a partial short circuit of the internal resistance wire, while a decrease in current may indicate an open circuit or poor contact. At the same time, observe the surface temperature of the heating section through the equipment temperature measurement points to avoid local overheating caused by stagnant medium flow.
Focus on checking whether the flameproof gap of the junction box exceeds the allowable value and whether the sealing ring is aged and hardened. After each maintenance, confirm that the flameproof surface is coated with anti-rust grease and fastened in place. It is strictly prohibited to open the wiring cavity while energized; after power-off, wait sufficient time for the internal capacitor to discharge.
When shutting down, cut off the power first, and disassemble only after the heating rod has naturally cooled to ambient temperature. If it is out of service for a long time, remove surface attachments and store it in a dry and ventilated place to avoid insulation dampness. Before restarting, measure the insulation resistance again and check the reliability of the wiring.
