Simple introduction of three roll skew rolled integral spiral finned tube and brazed spiral finned tube

The role of finned tube is simply the heat transfer. The following finned tube small compacts will introduce the three roll cross rolling integral spiral finned tube and brazed spiral fin tube.


1, three roll cross rolling integral type spiral finned tube: its production principle as shown in Figure 1.8 the overall type spiral fin tube three roll cross rolling, when the tube is lined with a mandrel, the driven roller blades, seamless steel tubes through the groove with the core head cavity on its outer surface machined fin. This method produces a fin tube through the tube and the outer fin is an organic whole, so there is no contact resistance loss and heat transfer with high efficiency. Compared with the welding method, the three roll rolling method has the advantages of high production efficiency, low consumption of raw materials and high heat exchange rate of the finned tube produced.


2. Brazed spiral finned tube: brazing spiral finned tube is processed in two steps. First, the steel strip plane is perpendicular to the axis of the pipe and is wrapped around the outer surface of the pipe by helix, and the ends of the steel strip are fixed on the steel pipe. Then, in order to eliminate the gap between the steel strip and the steel pipe, the brazing method is used to weld the steel strip and the steel pipe together. This method because of its high cost, it is commonly used in another way, the wrapped steel pipe into the groove of the whole hot galvanized zinc replacement. The whole hot galvanizing bath although not necessarily well into the gap between the minimum fin and tube, but on the surface of the fins and the outer surface of the steel pipe has formed a complete galvanized layer. The spiral finned tube which is made of galvanized steel is restricted by the thickness of zinc coating, and the zinc solution can not penetrate all the gaps, so the bonding rate between fins and steel tubes is still not high. In addition, the heat transfer coefficient of zinc is smaller than that of steel, so the heat transfer capacity is low. Zinc is extremely vulnerable to corrosion in acids, bases and sulfides. Therefore, the use of galvanized spiral finned tubes is not suitable for the production of air preheater.