Tubular electric heaters in heat transfer oil furnaces or asphalt tanks sometimes develop blackened tube walls and surface coking in less than one oil change cycle, and in severe cases the sheath burns through. After disassembly, it was found that in most cases the failure was not in the heating wire itself, but rather the sheath surface temperature exceeded the boundary allowed by the medium. When the oil flow rate is low or the liquid level fluctuates, the local oil film is continuously heated, light components volatilize, heavy components condense, and gradually form a coke layer on the tube wall. The coke layer further hinders heat dissipation, forming a vicious cycle.
During the design stage, the contact area between the sheath and the hot oil must be calculated. For heat transfer oil operating conditions, it is recommended to control the surface load within a reasonable range and ensure that the oil always immerses the heating section. The sheath development area of the GYY3-380/6 tubular electric heater matches the rated power, and it can reduce the risk of local overheating under both natural convection and forced circulation conditions. If the on-site oil tank is shallow or there is liquid level fluctuation, communicate with the manufacturer to adjust the tube length and mounting flange position so that the effective heating zone is completely below the liquid surface.
The internal control system of the electric heater automatically adjusts the output power based on the signal from the outlet temperature sensor, keeping the outlet medium temperature uniform. When the heating element overheats, an independent overheat protection device immediately cuts off the heating power supply, preventing coking, deterioration, and carbonization caused by overheating of the heated material, and also preventing burnout of the heating element, thereby extending the service life of the electric heater. For unattended circulation systems, it is recommended to connect the over-temperature signal to a host computer or audible and visual alarm.
This type of tubular electric heater can be used in industrial sectors such as aviation, shipbuilding, petroleum, chemical, machinery manufacturing, automotive, electrical machinery, radio, instrumentation, plastics, textiles, food, printing, and pharmaceutical and health care, for heating flowing or stationary liquids, air, and metal molds. When selecting a model, please provide the medium name, working temperature, container dimensions, and installation method so that the sheath material and surface load can be confirmed.
