U-shaped electric heating tube typical structure (common structure) generally consists of 5 parts: insulator, sealing material, lead-out rod, filler, heating wire, metal sheath tube, and terminal.
The spiral heating wire and lead-out rod are located in the center of the metal sheath tube. Its manufacturing process involves threading the spiral heating wire into a seamless steel tube, copper tube, or aluminum tube, and uniformly filling the gaps with an insulating and thermally conductive oxide medium, such as crystalline magnesium oxide powder (or aluminum oxide, clean quartz sand, etc.) using a multi-tube filling machine. Then, the tube diameter is reduced using a tube shrinking machine to compact the oxide medium (density reaching above 3.3g/cm³), ensuring that the heating wire is isolated from air and the center position does not shift to touch the tube wall. In this way, the heat output per unit area can be increased by more than ten times, and the service life can be correspondingly extended to over 10 years. Compared with electric heating elements of the same large heat output, tubular electric heating tubes can save 5% of heating material, while the thermal efficiency can reach over 90%.
Therefore, from the structure of the U-shaped electric heating tube, the metal tubular electric heating tube is currently a widely used, simple in structure, reliable in performance, and long-lasting sealed electric heating element. It can be successfully applied in industry and household appliances, and its use is becoming more widespread. It is hoped that more users will have a clear understanding of the structural principles of electric heating tubes.
