Which finned tube should be used for air cooled heat exchanger?
The basic forms of finned tubes for air coolers are: sleeve type, winding type, rolled sheet type, welded sheet type, elliptical tube type, inlaid sheet type, turbulent type, spoke type, slotted form and corrugated form.
The tube box structure of air coolers mainly includes flange type, pipe plug type and manifold type. Generally, flange type is used for medium and low pressure, and pipe plug type and manifold type are used for high pressure.
Processing technology of finned tubes
The manufacturing processes of finned tubes for air coolers mainly include integral forming, welding, high-frequency welding and mechanical connection. The integrally formed fins are integrated with the tubes, and the heat transfer, mechanical and thermal expansion properties are good, but the manufacturing cost is high, which is suitable for low-finned tubes (i.e. threaded tubes).
Welded fins can weld fins and tubes of different materials together, which is easy to manufacture, but the residue in the weld is not conducive to heat transfer, and the welding quality must be guaranteed. High-frequency welding fins use the high-frequency induction generated by the high-frequency generator to generate high temperature and partially melt at the contact point between the tube surface and the fin, and then pressurize the fin and the tube to form a whole. There is no flux or solder in the connection process. It is simple to manufacture and has excellent performance. It is the most widely used process in industry.
Application of air (wind) cooler
Air (wind) coolers are mainly used in walking machinery (excavators, loaders, forklifts, cranes, combine harvesters, road construction machinery, engineering machinery, etc.), and the working medium is forced to cool to the required temperature by air cooling.
Air cooler cleaning
Because most cooling water contains calcium, magnesium ions and acid carbonates. When cooling water flows through the metal surface, carbonates are generated.
Oxygen dissolved in cooling water can also cause metal corrosion and form rust. Due to the generation of rust, the heat exchange effect of the condenser decreases. In severe cases, cooling water has to be sprayed outside the shell. When the scaling is severe, the pipes will be blocked, making the heat exchange effect ineffective.
Datang Fin Tube research shows that scale deposits have a huge impact on heat transfer losses, and as deposits increase, energy costs will increase. Even a thin layer of scale will increase the operating costs of the scaled part of the equipment by more than 40%. Keeping the cooling channel free of mineral deposits can greatly improve efficiency, save energy, extend the service life of the equipment, and save production time and costs.
For a long time, traditional cleaning methods such as mechanical methods (scraping, brushing), high-pressure water, and chemical cleaning (pickling) have many problems when cleaning equipment: scale and other deposits cannot be completely removed, acid corrodes the equipment to form holes, and residual acid causes secondary corrosion or under-scale corrosion to the material, which ultimately leads to equipment replacement. In addition, the cleaning waste liquid is toxic and requires a lot of money for wastewater treatment.