The processing technology of steel-aluminum Extruded Type Finned Tube is to first process aluminum tube and steel tube into bimetallic composite tube, and then form fins after mechanical cold rolling.

There are two major types of finned tubes available with us, single metal tubes (also called mono metallic fin tube) and Bimetallic tube (composite extruded fin tube) .

The former uses Copper, Aluminum, and Copper Nickel alone. The later has a core tube on the inside made of harder material. In this case, the outer tube is rolled onto the core tube in order to provide for a tight bond and good thermal contact between the two tubes.

Finned tube is composite with iron-aluminum or copper-aluminum tube rolling out the fin, which feathers are tightness, small heat resistance, good heat transfer performance, high strength, small flow losses, strong corrosion resistant performance, not easy to deformation and a long working lifetime in cold and hot condition, etc.

Overall rolling fin is smooth and has no burr, so it is easy to clean. It is easy to make the fin surface wet and cooled with water when makes it cold during heating air-conditioning engineering. In the situation with drying, heating and other heat exchanging, its surface is handles by anodizing, which with beautiful color and luster, and can effectively prevent surface corrosion.

Aluminum rolling finned tube is rolling as a whole by the aluminum tube, which has the feather that no contact thermal resistance, high strength, thermal shock and mechanical shock, good thermal performance, and considerable expansion heat transfer surface. The heat ex-changer with this kind of finned tube is ahead of the string or around the plate ones.

Steel-Aluminum Extruded Type Finned Tube

The processing technology of steel-aluminum Extruded Type Finned Tube is to first process aluminum tube and steel tube into bimetallic composite tube, and then form fins after mechanical cold rolling. The aluminum fins are tightly combined into a bimetallic tube finned tube (composite extruded finned tube)

Steel-aluminum rolled finned tubes are integrally rolled from aluminum tubes, and have the characteristics of no contact thermal resistance, high strength, thermal shock resistance and mechanical shock resistance, good thermal performance, and a considerable expansion heat transfer surface. This finned tube heat exchanger is in front of the tube or around the plate.

Advantages

Transferring heat from a hot fluid into a colder fluid through a tube wall is the reason many of us use finned tubes.

But you may ask, what is the major advantage of using a finned tube? Why can’t you just use a regular tube to make this transfer? Well you can but the rate will be much slower.

By not using a finned tube the outside surface area is not significantly greater than the inside surface area. Because of that, the fluid with the lowest heat transfer coefficient will dictate the overall heat transfer rate. When the heat transfer coefficient of the fluid inside the tube is several times larger than that of the fluid outside the tube the overall heat transfer rate can be greatly improved by increasing the outside surface area of the tube.

Finned tubes increase outside the surface area. By having a finned tube in place, it increases the overall heat transfer rate. This then decreases the total number of tubes required for a given application which then also reduces overall equipment size and can in the long-run decrease the cost of the project. In many application cases, one finned tube replaces six or more bare tubes at less than 1/3 the cost and 1/4 the volume.

For applications that involve the transfer of heat from a hot fluid to a colder fluid through a tube wall, fin tubes are used. Usually, for an air heat exchanger, where one of the fluids is air or some other gas, the air side heat transfer coefficient will be much lower, so additional heat transfer surface area or a fin tube exchanger is very useful. The overall pattern flow of a finned tube exchanger is often crossflow, however, it can also be parallel flow or counterflow.

Fins are used to increase the effective surface area of heat exchanger tubing. Furthermore, finned tubes are used when the heat transfer coefficient on the outside of the tubes is appreciably lower than that on the inside. In other words, heat transferred from liquid to gas, vapor to gas, such as steam to air heat exchanger, and thermic fluid to air heat exchanger.

The rate at which such heat transfer can occur depends on three factors – [1] the temperature difference between the two fluids; [2] the heat transfer coefficient between each of the fluids and the tube wall; and [3] the surface area to which each fluid is exposed.

Finned tubes are used because they help

Increase Heat Transfer Rate

A finned tube exchanger typically has tubes with fins attached to the outside. Usually, there will be some liquid flowing through the inside of the tubes and air or some other gas flowing outside the tubes, where the additional heat transfer surface area due to the finned tube increases the heat transfer rate. In a crossflow fin tube exchanger, the fins will typically be radial fins and they’ll either be circular or square in shape.

Improve Heat Transfer Coefficient

By not using a finned tube, the outside surface area is not significantly greater than the inside surface area. Because of this, the fluid with the lowest heat transfer coefficient will dictate the overall heat transfer rate. When the heat transfer coefficient of the fluid inside the tube is several times larger than that of the fluid outside the tube, the overall heat transfer rate can be greatly improved by increasing the outside surface area of the tube.

Increase Outside Surface Area

By having a finned tube in place, it increases the overall heat transfer rate. Finned tubes increase the outside surface area. This decreases the total number of tubes required for a given application which then also reduces overall equipment size and can in the long-run decrease the cost of the project.

Finned tube heat exchangers are used in a variety of applications, and more so as industrial heat exchangers. An air heat exchanger like the evaporator coil in an air conditioning unit is typically a fin tube exchanger. Another common fin tube air heat exchanger is the car radiator. The purpose of the car radiator is to cool the hot water in the tubes with the air passing through the crossflow. On the contrary, the air conditioner evaporator coil has the purpose of cooling the air passing through it. The finned tubes that are manufactured at Kainon Boilers, use high grade carbon steel, stainless steel, copper, brass, and aluminum. Our finned tube exchangers are designed to meet the specific duty condition, temperature and pressure of the fluids.