The voltage range of each country is different (100V-440V), the power range of the electric heating tube is different (100W-5000W), the use environment is different, the diameter of the electric heating tube is different, etc., which requires the design requirements and manufacturing process of the resistance wire of the product to be higher and higher. In China, although the electric heating tube has been produced for 20 years, but the electric heating tube manufacturing technology is still very backward, many products with small rated voltage but large rated power due to the limitation of the production process, so that the diameter of the single resistance wire is large so that the strength of the resistance wire is too high, resulting in the wire winding machine can not be wound, the welding place of the resistance wire ring and the lead rod during the powder loading process and shrinking process is easy to pull off, resulting in the problem that the length of the electric heating tube tube is more than 1500mm can not be manufactured; For the pipe selected for household electric heating tube (C>6. 2mm, 6. 5mm, 8. 0 mm, 8. 5mm), per prodotti con tensione nominale ridotta e potenza nominale elevata, per soddisfare i requisiti di resistenza, se viene utilizzata una singola struttura del filo di resistenza, il diametro del filo di resistenza deve essere aumentato, con conseguente eccessiva resistenza alla flessione del filo di resistenza e la distanza di avvolgimento tra il diametro esterno dell'anello del filo di resistenza e la parete interna del tubo di riscaldamento elettrico è troppo breve, il che influisce seriamente sulle prestazioni elettriche del tubo di riscaldamento elettrico.
