The heat exchange tube is one of the components of the heat exchanger. It is placed inside the cylinder and is used for heat exchange between two media. It has high thermal conductivity and good isothermal properties. It is a device that can quickly transfer heat energy from one point to another with almost no heat loss, so it is called a heat transfer superconductor. Its thermal conductivity is thousands of times that of copper. Heat exchange tubes are divided into different types according to different shapes and uses.

Different types of heat exchange tubes
1. U-tube: U-tube is a common type of heat exchange tube, suitable for occasions with relatively high requirements for heat exchange area. Its advantages are small pipe curvature, large heat exchange area, and suitable for heat exchange under low temperature difference. The disadvantage is that the manufacturing process requirements are high and the cost is relatively high.
2. S-tube: S-tube is a type of heat exchange tube with beautiful shape and low difficulty in making. It has efficient heat transfer performance and pressure balance ability, and is suitable for working environments under various pressures. In addition to heat exchange, S-tube can also be used in processes such as distillation and adsorption.
3. Spiral tube: Spiral tube is mainly made of a spiral roll. Because it has its own flow path, there is essentially no hard connection between the inside and outside. Spiral tube has excellent heat exchange performance and strong self-cleaning ability, and is particularly suitable for heat exchange needs in dirty environments.

Selection points
Choosing a suitable heat exchange tube is not only related to the performance of the heat exchange equipment, but also to the safety and maintenance cost of the equipment. The following are the key points to consider when selecting:
1. Heat exchange conditions: Such as flow, temperature, pressure, etc.
2. Medium material: Such as fluid properties, impurity content, etc.
3. Equipment use: such as the occasion where the heat exchanger is used, the characteristics of the environment, etc.
4. Equipment safety: Such as necessary safety protection measures, installation methods, etc.

Common faults and solutions
1. Scaling and fouling: When there is a lot of dirt on the surface of the heat exchange tube, it will have an adverse effect on the heat exchange effect. At this time, physical and chemical methods can be used for cleaning, such as high-pressure water, step backwashing, etc.
2. Rust: Especially in areas with hard water, rust is easy to form on the inner wall of the pipe. To prevent the formation of rust, the pipe should be cleaned regularly with a cleaning agent.
3. Pipe cracking: During use, the heat exchange tube is often subject to changes in temperature and pressure. Excessive temperature changes and pressure changes may cause the tube to crack. At this time, the tube needs to be replaced or other maintenance measures need to be taken.

Summary
Heat exchange tubes are a common type of heat exchange equipment in industrial production. Their selection and maintenance play an important role in the performance and safety of the equipment. When selecting, it is necessary to comprehensively consider the advantages and disadvantages of different models and make a choice based on the application environment and actual needs. During maintenance, the tubes need to be cleaned regularly to prevent failures and accidents.