1. The design of the heating tube should consider the factors of thermal expansion and contraction, ablation, oxidation, creep, etc., so as to avoid failure due to deformation during normal work.
2. The design of the internal structure of the heating tube should ensure that the highest temperature of the material used for manufacturing the heating tube.
3. The design of the welding structure of the heating pipe should comply with the relevant standards. The welding seam of the pressure heating pipe, especially the part in the container, should be as few as possible, and the setting of the welding seam should be convenient checking.
4. The heating tube (including the end) must be sealed.
5. The heating tube used for the heating of aggressive media must use corrosion-resistant metal tube or a protective sleeve to ensure the working life of the heating tube.
6. When the outer shell of the heating tube is ordinary steel or other alloy materials the wall thickness should not be less than 0.35mm. When the outer shell is copper or copper alloy and other materials, it must be made according to the corresponding mechanical strength and adapt to the harsh working environment.
7. The bending radius of the heating tube should not be less than 2.5 times the diameter of the heating tube.
8. The curved shape of the heating tube must ensure that the inner end of the lead rod is on the straight part of the tube, and the distance from the bending position should not be less than 10mm.
9. The distance between the exposed lead wire and the shell should not be less than 1mm.
10. The cross-sectional area of the lead wire should not be less than 7 times the cross-sectional area of the heating wire.