Both use tubular electric heating elements as the heating core, and the difference lies in the medium and structure. Sheathed electric heaters usually place the heating element inside a metal sheath and transfer heat through the sheath wall to air, water, or oil media, making them suitable for pipeline tracing, tank heating, and small thermal oil systems; thermal oil electric heater equipment uses a flange-insertion structure, directly immersing U-shaped tubular heating elements in flowing thermal oil, and works with a circulation pump and temperature control system for higher-power process heating. When selecting a model, it should be determined based on the medium type, flow rate, required power, and installation space.
This model has a rated voltage of single-phase 220V and a rated power of 8kW. The sheath material can be stainless steel or carbon steel. The surface heating power is recommended not to exceed 3W/cm², and the specific value must be calculated according to the medium and sheath length. The insulation resistance should be no less than 50MΩ in the cold state, and the withstand voltage test is performed at 1500V/1min. The terminals use high-temperature-resistant ceramic sleeves or sealed connectors, and the protection rating can be configured as IP54 or higher. During design and selection, the power supply capacity, conductor cross-section, and temperature control circuit must be checked to avoid long-term overload operation.
When the heating space is limited, the medium should not directly contact the heating wire, or regular extraction for maintenance is required, a sheathed structure is more suitable. For example: pipeline tracing and freeze protection, water tank and oil tank insulation, auxiliary heating for small thermal oil furnaces, and air heating ducts. For high-viscosity media or conditions prone to scaling, the sheath spacing should be increased and a detachable design should be considered to reduce maintenance difficulty. If the medium is in a flammable and explosive environment, products with the corresponding explosion-proof rating should be selected and equipped with interlock protection.
