Finned tube is to improve the heat transfer efficiency, usually in the surface of the heat transfer tube through the installation of fins, increasing the surface area of the heat transfer tube in order to achieve the purpose of improving the efficiency of heat transfer, such a heat transfer tube called finned tube.
According to the fin structure characteristics: According to the fin shape and structure, finned tube can be divided into the following categories, square tube, spiral finned tube, longitudinal finned tube, spiral serrated finned tube, tube. According to the fin tube fin material and the same material can be divided into single metal finned tube and bimetallic composite finned tube.
According to the different processing technology of finned tube, finned tube can be divided into rolling finned tube, welded finned tube (high frequency welding finned tube), roll forming finned tube, set forming finned tube. Finned tube as a heat exchanger element, lasting work in high temperature flue gas conditions, such as boiler heat exchanger with finned tube, the use of harsh environment, high temperature and pressure and in a corrosive atmosphere, which requires finned tube should have a high Functional indicators. Anti-corrosion, wear resistance, low contact resistance, high does not change performance, anti-fouling ability. Set fins: Set fins are preformed with a single piece of fins, and then the fins are set on the outer surface of the pipe by manual or mechanical means at a similar height (wing distance). It is the first application of a method of processing finned tubes. Because the package process is simple, the skills are not demanding, the equipment used inexpensive, and easy to repair, so until now there are still many workshops in use. This process is a labor-intensive process, suitable for general small factories or funds and technical conditions are not high enterprises. Artificial suit is called manual set. It is by means of tools, relying on the power of people will be one by one into the wings. This method because the fin of the pressure into the limited, so the package of small interference, the fins prone to loose phenomenon. The mechanical suit fins are carried out on the fins of the fins. Because the fin press is by mechanical impact or liquid pressure, pressure into the force, so you can use a larger amount of interference. The strength between the fins and the tube is high and is not easy to loosen. Mechanical transmission of the set machine high productivity, but the noise, poor security, poor labor conditions. Although the hydraulic drive does not exist the above problems, but the equipment is more expensive, the use of maintenance personnel skills required higher, its productivity is also lower. Embedded spiral fins: embedded spiral finned tube is pre-processed in the steel pipe with the same width and depth of the spiral groove, and then in the lathe on the steel strip embedded in the steel. In the process of winding around the winding, because there is a certain preload, the strip will be tightly in the spiral groove, thus ensuring a certain contact between the steel and steel pipe surface or surface contact. In order to prevent the strip from falling back, the ends of the strip are to be welded to the pipe. For easy embedding, there should be a certain backlash between the strip and the spiral groove. If the backlash is too small to form an interference, the embedding process is difficult to proceed smoothly. In addition, the winding around the strip will always have a certain rebound, the result will make the steel and spiral groove bottom contact is not good enough. Embedded fins can be carried out in general equipment, the cost is not high, but the process of complex production efficiency is low.