I Core Structure Composition
1. Heating core: The core heating unit features nickel-chromium/iron-chromium-aluminum alloy heating wires inside, with high-purity magnesium oxide powder filling the gaps as an insulating and heat-conducting medium. It commonly adopts a U-shaped multi-tube arrangement to expand the effective heating area.
2. Jacket body: The outer layer features a seamless metal jacket (304/316L stainless steel or carbon steel available), which completely isolates the heating core from the oil. The wall thickness is typically ≥3mm, providing pressure resistance and corrosion resistance.
3. Flange connection disc: Standard industrial flange (compliant with GB/HG/ANSI standards), fixed to the tank opening via bolts, and leak-proof installation achieved with matching gaskets; flange material matches the sleeve pipe.
4. Explosion-proof junction box: Standard explosion-proof type junction box (conventional explosion-proof rating Exd ⅡBT4) for oil tank scenarios, isolating internal electrical sparks from the external flammable gas environment to meet safety requirements in flammable and explosive areas.
5. Temperature Control Protection Component: Equipped with a PT100 temperature sensor and a temperature control system to achieve constant temperature control. It features built-in overtemperature power-off protection to prevent dry burning and overheating-related safety risks.
II. Working Principle
Based on the thermal effect of electric current (Joule's Law), the internal electric heating wire converts electrical energy into thermal energy upon power-on. The heat is uniformly conducted to the outer wall of the metal sheath through the magnesium oxide insulation layer, and then transferred to the oil inside the tank via heat exchange, raising and maintaining the oil temperature above its freezing point.
Integrated with the temperature control system, it enables automatic start-stop functionality: heating is automatically initiated when the tank temperature falls below the set lower limit (e.g., 5°C) and ceases when reaching the upper limit (e.g., 15°C), ensuring both freeze protection and energy-efficient operation.
III Core advantages of adapting to oil tank scenarios
1. Oil free maintenance, low operation and maintenance costs
The protective sheath completely isolates the heating element from the oil, so there is no need to discharge the oil in the tank during maintenance and replacement. Only the internal heating element can be removed after power is cut off, and there is no need to stop production and empty the storage tank, greatly reducing maintenance time and material loss.
2. Low surface load to prevent oil carbonization
Design low surface heat load (usually controlled at 1.5~3W/cm ²) for the heating characteristics of oil products, with uniform heating and no local high temperature, to avoid oil coking and carbonization due to overheating, ensure oil quality, and extend the service life of heating tubes.
3. Explosion proof sealing, suitable for flammable and explosive environments
Explosion proof junction box with flange static sealing structure, in compliance with explosion-proof safety regulations for petrochemical sites, can be safely used for flammable and explosive oil storage tanks such as diesel, lubricating oil, and heavy oil, eliminating the risk of electric sparks igniting oil and gas.
4. Easy installation and strong adaptability
The standard flange interface can directly match the reserved openings on the side walls and bottom of the storage tank, and installation does not require complex hot work operations; Power, length, and flange specifications can be customized according to the size of the storage tank and the characteristics of the oil product.
5. High thermal efficiency and stable antifreeze effect
Immersion direct heating, with a thermal efficiency of over 95%; The multi tube core structure has a large heating area and uniform temperature distribution inside the tank, which can stably maintain the temperature of the oil and prevent low-temperature solidification and viscosity increase from affecting pumping and use.
Ⅳ Key points for selecting antifreeze scenarios for oil tanks
1. Material selection
Ordinary diesel, lubricating oil, and non corrosive oil: 304 stainless steel sheath is selected for high cost-effectiveness
Sulfur containing crude oil, corrosive solvents, and heavy oil: 316L stainless steel sheath is selected for stronger corrosion resistance
2. Power accounting
The anti freezing and insulation scenario can be initially estimated at 0.5-1.5 kW per cubic meter of oil, and the final heat load needs to be accurately calculated based on the tank volume, minimum ambient temperature, oil solidification point, and insulation layer thickness of the tank.
3. Flange specifications
Commonly used standard flanges such as DN50, DN80, DN100, etc., with pressure ratings that match the design pressure of the storage tank; Prioritize using flange standards consistent with the storage tank to ensure sealing and installation compatibility.
4. Electrical parameters
Single power ≤ 3kW can choose 220V single-phase power supply, and high-power models use 380V three-phase power supply to ensure three-phase load balance.
5. Temperature control configuration
Equipped with PT100 temperature sensor and digital temperature controller as standard, it is recommended to additionally configure over temperature protection and low liquid level protection interlock to prevent dry burning and overheating.
Ⅴ Installation and maintenance precautions
Installation requirements
1. The heating section must be completely immersed in the oil, and the lowest liquid level must be at least 50mm above the upper edge of the heating section. Dry burning is strictly prohibited; Prioritize installation on the lower side wall of the storage tank, avoiding installation in the top area with large liquid level fluctuations.
2. Install oil resistant and temperature resistant sealing gaskets (nitrile rubber, flexible graphite material) on the flange contact surface, and tighten the bolts evenly diagonally to prevent oil and gas leakage.
3. Strictly follow the explosion-proof electrical specifications for wiring in the explosion-proof area, seal and block the inlet of the junction box, and ensure reliable grounding of the equipment casing; Equipped with residual current circuit breakers and overload protectors.
When multiple sets of heating tubes are installed in parallel, the spacing between the tubes should not be less than three times the diameter of the tube to avoid local heat accumulation and oil overheating.
routine maintenance
1. Regularly check the sealing surface of flanges and junction boxes to prevent oil, gas, and water vapor from entering the interior and causing short circuits.
2. Check the cold insulation resistance every 3-6 months, and the resistance value should not be less than 2M Ω. If it is lower than the threshold, timely maintenance is required.
Before restarting after long-term disuse, it is necessary to check the insulation performance and sealing status, and confirm that they are correct before powering on.
If carbon or scale accumulates on the surface of the sheath, the core can be removed and the outer wall of the sheath can be cleaned to restore heat transfer efficiency.
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Post time: Jul-22-2026
