In industrial fluid heating and tank tracing scenarios, the surface load and heat dissipation conditions of an electric heater directly determine the service life of the element. Taking a commonly used 304 stainless steel sheathed electric heater as an example, when the surface load exceeds 3.5 W/cm² and the medium flow rate is below 0.1 m/s, the sheath temperature may exceed the allowable upper limit of the material, leading to accelerated oxidation. The JHD-75 industrial electric heater is designed for such operating conditions, with a rated surface load controlled within 2.8 W/cm², and the output power variation is calculated according to the supply voltage fluctuation range (±10%). It is equipped with over-temperature protection and an interlock control loop that cuts off the heating output when the temperature exceeds the set value.
Traditional bare resistance wire is directly immersed in liquid for heating. Although the thermal response is fast, it places high demands on medium cleanliness and is susceptible to electrochemical corrosion. The JHD-75 adopts a sheathed structure, isolating the heating element from the medium. The outer sheath material can be selected from 304 stainless steel, 310S stainless steel, or NCF800 alloy. In media containing chloride ions or weakly acidic media, the intergranular corrosion resistance of the 310S stainless steel sheath is superior to that of 304 stainless steel; NCF800 is suitable for higher temperature ranges, with NiCr8020 as the resistance material, and the maximum outer sheath temperature of the heating element can reach 750°C. For intermittent heating applications requiring frequent start-stop cycles, the sheathed structure can reduce mechanical damage to the resistance wire caused by thermal shock.
This model is suitable for three-phase 380V or single-phase 220V power supply, with a rated power of 75kW (customizable for non-standard requirements). During the design stage, the impact of supply voltage fluctuation on output power must be calculated: when the voltage deviation is ±10%, the power change of a resistive load is approximately ±21%, so a power margin should be reserved during model selection. The control loop is provided with independent over-temperature protection. When the temperature sensing element detects that the sheath temperature exceeds the set threshold, the interlock cuts off the contactor and outputs an alarm signal. For unattended tank tracing systems, this interlock logic can prevent dry-burn damage caused by medium drainage or low liquid level.
Compared with flanged electric heating tubes, the JHD-75 uses threaded or flanged connections, making it easy to install on the side wall of a tank or on a pipeline. During maintenance, note that the surface temperature of the heating element may still be high after power-off. It should be allowed to cool naturally to a safe temperature before disassembly to avoid burns or sheath cracking caused by rapid cooling. In media requiring regular cleaning, a removable core structure is recommended to facilitate separate replacement of the heating core and reduce downtime.
Suitable for scenarios such as auxiliary heating of thermal oil furnaces, water treatment preheating, chemical tank tracing, and heating of low-flow-rate media. Under operating conditions with low ambient temperature or high medium viscosity, it is recommended to use it together with insulation layers to reduce heat loss. For explosion-proof areas, an explosion-proof terminal enclosure must be separately selected and installed and accepted in accordance with relevant specifications.
