Finned radiator is one of the most widely used heat exchangers in gas and liquid heat transfe. The heat transfer enhancement can be achieved by adding fins on the common base tube. The base pipe can be made of steel pipe, stainless steel pipe, copper pipe, etc.. Fins can also be used steel strips, stainless steel strips, copper strips, aluminum strips, etc.
Fin type heat exchanger is mainly used for air heating and drying system. A fin type heat exchanger is the main equipment of hot blast device. The heat radiator medium can be steam or hot water, can also be used to heat conduction oil, vapor pressure is generally not more than 0.8Mpa, the hot air temperature at 150 Deg C.
The fin type radiator is mainly composed of three rows of side-by-side spiral finned tubes arranged in the direction of air flow. The processing technology of SRZ type fin tube bundle is mechanical wound steel strip 0.5*10 mm onto seamless steel pipe,which is around 18 mm OD, and then hot galvanized it. Stainless steel pipe and stainless steel belt can also be made of stainless steel heat radiator is SRL type fin radiator steel and aluminum strip rolling, cooling area of the unit the length of more than SRZ.
Fin type heat exchanger adopts a mechanical winding sheet, radiating fin and heat pipe with large contact surface and compact, good heat transfer performance, stability, the air resistance is small, steam or hot water flowing through the pipe, heat through fins passed heat and heater the cooling air.
Selection of pipe spacing and fins pitch.
Generally, the fin pitch and fin height mainly affect the fin ratio, and the fin ratio has a great relationship with the heat transfer coefficient of the medium inside and outside the tube. If the difference of heat transfer coefficient between inner and outer tubes is big, the fin tube with larger fin ratio should be chosen, such as steam heating air. When there is phase transition in one side, the difference of heat transfer coefficient will be greater, such as the exchange of hot and cold air, and the fin tube heat exchanger can be used when the hot air drops below dew point. In the case of no phase change air or air heat exchange, or the heat exchange between water and water, usually the bare pipe is more suitable. Of course, the low finned tube can also be used, because at this time it belongs to the weak heat transfer coefficient, and the strengthening of any side of the tube has a certain effect. However, the effect of excessive fin ratio is not obvious, and the best inside and outside contact area of the tube can be strengthened simultaneously. Can use threaded tube or low fin tube.
The fin pitch is mainly considering dust, dirt, easy cleaning and other factors, meanwhile need to strictly comply with the requirements of equipment pressure drop. When arranging, the distance between the pipe and the tube is not too large, and the general >1mm is suitable for the pipe laying. In the process of heat exchange, when the air flows through the finned tube heat exchanger, the two sides of the fin are involved in the heat exchange. There is only a small amount of radiation heat transfer in the middle part of the two finned tubes, and the heat transfer effect is not obvious. Because there is no fins and no resistance, the air is easy to penetrate. In the process of heating the air, without cold air heat will pass through the middle fin and heated hot air to form neutral, but reduces the heat transfer effect, compared with foreign finned tube heat exchanger, tube spacing is larger than the diameter only 0.5mm, From here we see that the tube spacing are importance to fin tube.
Publisher:Lord Fin Tube