Heating tube knowledge

Heating tube, also known as electric heating tube, is a common type of electric heating element. Here is detailed knowledge:
1、 Basic Structure and Principle
Structural composition
The heating tube is mainly composed of metal tubes (such as stainless steel tubes, copper tubes, etc.), spiral resistance wires (usually nickel chromium alloy wires), magnesium oxide powder (insulating thermal conductive material), and lead out rods (used to connect to power sources). The metal tube provides a protective shell, and the resistance wire is the core component that generates heat. Magnesium oxide powder is filled around the resistance wire to provide insulation and thermal conductivity. The lead out rod connects the resistance wire to an external power source.

working principle
When current passes through a resistance wire, according to Joule's law, the wire generates heat. Due to the tightly wrapped resistance wire by magnesium oxide powder, heat can be efficiently conducted to the surface of the metal tube through the magnesium oxide powder, and then transferred to the heated object.
2、 Material characteristics
Metal tube material
Stainless steel pipe: It has good corrosion resistance, high temperature resistance, and mechanical strength. For example, 304 stainless steel is commonly used in general liquid heating applications, such as heating pipes in water heaters; 316 stainless steel is suitable for more harsh environments, such as industrial heating equipment containing corrosive components.
Copper tube: Good thermal conductivity, but relatively weak corrosion resistance. Generally used in situations where high thermal conductivity is required and the environment is relatively mild, such as some small experimental heating devices.

Resistance wire material
Nickel chromium alloy wire: It is the most commonly used material for resistance wires. It has a high electrical resistivity, can generate sufficient heat when passing current, and has good oxidation resistance. It can work stably for a long time at high temperatures.

Insulation and Thermal Conductive Material - Magnesium Oxide Powder
Magnesium oxide powder is a white powdery substance with a high thermal conductivity, which can effectively dissipate the heat generated by the resistance wire. At the same time, it has excellent insulation performance and high voltage resistance, which can prevent short circuits between the resistance wire and the metal tube, ensuring the safe use of the heating tube.