The submerged electric heating core is mainly used for heating the contacting fluid. It has the characteristics of fast heat exchange and high thermal efficiency. It can heat the medium such as water, oil, gas and so on. The maximum surface thermal load of the heating element allowed by different heating medium is not the same, and its value is closely related to the physical and chemical characteristics of the heating medium. If the selection is improper, it will cause serious problems. If the value is too high, the surface temperature of the heating element will rise sharply, and the service life will be reduced. Moreover, the heating medium will be deteriorated due to excessive heating. If the value is too small, it will lead to an increase in the volume of the heater, resulting in a dramatic increase in cost. Different surface loads are applied to electric heaters of different uses,. Structure on the tube plate flange carries a plurality of heating elements (heating), electric heating tube set in different parts of support plate to fix the electric heating tube, reduce the vibration caused by medium flow, to prevent the heating pipe for heating pipe and tube may occur in contact. The heater can set a temperature control device or overtemperature protection device in the setting of the flameproof wiring to achieve the temperature control or prevent the medium from flowing dry.