When many customers inquire the electric heaters, they often complain that the quality of the electric heater which they used before is very bad and the electric heater lift is short. What is the reason? What internal factors affect the service life of electric heaters?
As normal the factors affecting the life of the electric heater in different application are different. Let us first talk about the impact of dry air drying on the life of the electric heater.
The electric heater used in heating air include die heating elements, U-shaped tubular heaters, finned air tubular heaters and other tubular heaters.
1, mold heating elements
a. When using the mold to heat the tube, the hole diameter of the mold hole is 0.1-0.2 mm larger than the diameter of the heating tube. Because the air has a hindrance to the heat conduction of the heating pipe, if the gap between the hole diameter of the die hole and the pipe diameter of the heating pipe is too large, the mold can not absorb the heat generated by the heating pipe in time, which will cause the surface of the heating pipe of the mold. When the temperature rises and the internal temperature is too large, the heating tube may expand or squib, or the resistance wire may be blown to a certain extent, resulting in a shortened life of the mold heating tube.
b. Before designing the mold heating tube, determine the working temperature of the heating tube and use the heating tube material suitable for the working temperature. And to carry out a certain temperature control, to prevent the operating temperature is too high and burn the electric heating tube.
c. If the mold vibrates during operation, the resistance wire of the single-head heating tube of the mold should select a nickel-chromium wire with better flexibility to prevent the heating tube from breaking due to vibration.
2, U shaped tubular heaters and finned air tubular heaters and other dry heaters.
a. The heating pipe should be controlled at 1KW per meter when the air is dry, and 1.5KW when there is fan circulation. Exceeding this standard, the surface load of the heating pipe is too large, so the surface temperature of the heating pipe will increase. As a result, the internal temperature of the heating pipe is too high and the resistance wire is burnt out. In severe cases, the tube is inflated and a tube bursting phenomenon occurs, thereby shortening the service life of the heating tube.
b. According to the working temperature, choose the appropriate heating pipe material. For example, if the working temperature of the oven is 600 degrees, you can not use the material of stainless steel 304 with temperature resistance of 300-400 degrees. It is necessary to use stainless steel 310s which can withstand temperature of 700 degrees. And to carry out a certain temperature control, to prevent the operating temperature is too high and burn the electric heating tube. If you do not choose the right material, or if you do not control the temperature, the life of the heating tube will be shortened.
