Introduction to the types of convector finned tube radiator
at present, the finned tubes used for convective radiators mainly include high-frequency welded finned tubes, copper tubes with aluminum fins, L-shaped aluminum fins, and rolled finned tubes. As the saying goes, if you are not afraid of not knowing the goods, you are afraid of comparing the goods. Now these kinds of finned tubes are compared one by one
I. high frequency welded finned tubes are formed by winding steel strips on the steel tubes and welding with high-frequency current while winding. Its advantage is low cost. Among the commonly used materials for radiators, steel strip should be the cheapest material to affect the development of new aluminum powder materials. Its disadvantages are: 1) high frequency welding consumes high power and is known as the electric tiger. 2) Generally, the full welding is not achieved, and the contact thermal resistance is large. 3) Due to process limitations, the height of the film is generally no more than 15 mm, and the film spacing is large, so the heat dissipation area is not large enough, and the thermal efficiency is not high. 4) Steel pipes and steel strips are easy to rust. When plastic pipes are used for heating pipes, steel pipes are also used for radiator waterways, which is dwarfed. Some producers have realized that this is a transitional product to choose imported high reliability compactors
second, the copper tube string aluminum sheet is a round or square aluminum sheet punched with aluminum foil on the thin-walled copper tube, and then the tube expansion technology is used to eliminate the gap between the copper tube and the aluminum sheet. Its advantage is that the aluminum sheet can be made into any size without restriction. Its disadvantages are: 1) because aluminum is softer than copper, no matter what kind of tube expansion technology is used, the combination of the two cannot be very tight. Coupled with the change of thermal expansion and cold contraction, it will loosen over time. Once loosened, the thermal efficiency will be greatly reduced. 2) Aluminum foil is very soft, even if pressed with a few ribs, it can't change its weak nature. It will fall down as soon as it is touched, which is not easy to clean. Professor xiaoyuerong pointed out: "durable and reliable, the first requirement of the product is corrosion resistance, and the other should also include strength and rigidity. These should be the first requirements for light radiators in China." It is an undeniable fact that the rigidity of copper tube string aluminum sheet is very poor, but many people almost forget this when evaluating this product. 3) In order to reduce costs, manufacturers have thinner and thinner copper tubes, which will not be corroded. It is unrealistic that copper tube air coolers have been used in industry for a long time, and the phenomenon of copper tube corrosion also occurs from time to time. 4) There are many production processes and the production efficiency is not high. However, it has broad prospects for use.
Third, L-shaped finned tubes are made of L-shaped fins wrapped with aluminum strips on steel or copper tubes. In industrial air coolers, compared with rolled finned tubes, L-shaped wound tubes are replaced products. The reasons are as follows: 1) the connection is not tight, and the contact pressure is only one fifth of that of rolled finned tubes. When the tube wall temperature exceeds 70 ℃, the L-shaped fins begin to loosen and the contact thermal resistance increases. 2) The fins are wound with aluminum strip (0.6mm thick). Although there is tensile deformation in the winding, the cold work hardening is not enough, and the fins are soft and fall down when touched, resulting in poor reliability
IV. The Progressiveness of rolled finned tubes was highlighted as early as the 1940s. In the book "heat exchanger", comparing various kinds of finned tubes, the rolled finned tubes ranked first in many performances. It is a substitute product for L-shaped finned tubes. The new generation of rolling finned tube forming machine developed by Beijing Kyoto spark energy saving Technology Development Co., Ltd. can roll four series of finned tubes: steel aluminum composite, copper aluminum composite, plastic aluminum composite, and pure aluminum. The fin spacing is 5.8 mm, the fin height is not less than 22 mm, the fin section is trapezoidal, and the fin top thickness is 0.35 mm. The advantages of rolled finned tubes are: 1) the combination is very close, and the contact pressure can reach 75 kg/cm2, so it will never loosen under the condition of repeated changes of cold and heat. 2) Fins are formed by cold extrusion of aluminum tubes. After cold work hardening, aluminum fins are very rigid, durable and reliable. 3) High thermal efficiency. 4) When PEX or Pb plastic pipe is used as the base pipe, it is the radiator with 50 years of service life. 5) The production process is simple. From raw materials to qualified products, it can produce 300 meters a day by two people. In addition, the production cost should be equivalent to that of L-shaped finned tubes. Professor xiaoyuerong pointed out that convector is a kind of radiator with development prospects
to sum up, using plastic aluminum composite rolled finned tubes as heat dissipation elements of convectors should be the first and the first choice. Plastic 2. Put forward higher requirements for the clamping jaw of the experimental machine: the clamping surface is long, has high hardness and toughness, and the clamping tooth surface has been treated with a certain technology; Aluminum composite rolled finned tube convector is a new product that advances with the times. Beijing Jingdu Xinghuo Energy Saving Technology Development Co., Ltd. has made a lot of efforts to develop this new product and made a new contribution to the development of light radiators in China. (end)
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