Finned condenser is mainly used for air heating in drying system and is the main equipment in hot air device. The heat medium used by radiator can be steam or hot water, or heat transfer oil. The working pressure of steam is generally not more than 0.8Mpa, and the temperature of hot air is below 150℃. Finned radiator is mainly composed of three rows of parallel spiral finned tube bundles between air flow direction. The processing technology of heat dissipation finned tube bundle is to wind 0.5*10mm steel strip on seamless steel pipe by mechanical winding method, and then hot dip galvanize. Stainless steel pipe and stainless steel strip can also be used to make all stainless steel radiator. SRL type radiator is a finned radiator rolled by steel pipe and aluminum strip. Its heat dissipation area per unit length is larger than that of SRZ type. Due to mechanical winding, the contact surface between the heat dissipation fin and the heat dissipation tube is large and tight, the heat transfer performance is good and stable, the air passing resistance is small, steam or hot water flows through the steel pipe, and the heat is transferred to the air passing through the fins through the fins tightly wound on the steel pipe, so as to achieve the effect of heating and cooling the air.