A common problem in on-site operation and maintenance is: the heat transfer oil furnace heats up slowly, and when inspected, the pipe wall is found to have coking and carbon deposits, and draining the oil to replace the heating element is time-consuming and laborious. If the heater structure is improperly selected, a single maintenance often requires several hours of downtime. For occasions with frequent maintenance or continuous production, a sheathed tubular electric heater can be considered. When replacing the core, there is no need to drain the medium, reducing downtime.
Ordinary tubular electric heaters have a simple structure and low cost, and are suitable for general heating scenarios, but the heating core is in direct contact with the medium, and the pipeline must be drained during maintenance. The sheathed structure places the heating core inside a metal sheath, and the core can be pulled out and replaced separately while the medium remains in the system. For equipment such as heat transfer oil furnaces and asphalt tanks that are inconvenient to drain frequently, this feature helps reduce maintenance workload.
The surface temperature of this type of heater is generally controlled at 150~450°C, with a maximum not exceeding 550°C, and the thermal efficiency is not less than 90%. Compared with heat treatment radiant tubes, the surface temperature is lower, and the thermal impact on the medium is relatively mild. The FGR-40 model has a power of 40kW at 380V, and the sheath material can be carbon steel or stainless steel according to the corrosiveness of the medium.
When selecting on site, first confirm the medium type and working temperature, then check the installation interface dimensions and wiring method. If the medium is prone to coking or maintenance is frequent, give priority to the sheathed type; if it is general water or air heating and the maintenance cycle is long, an ordinary tubular heater can also meet the requirements. During installation, ensure that the heating zone is fully immersed in the medium to avoid dry burning.
