Serrated finned tube is a type of heat exchanger that is designed to enhance the heat transfer rate by increasing the surface area of the tube.
Download PDFSerrated Finned Tube is a high-frequency welding production process with high-frequency patented technology. Using high-frequency power supply as a heat source, the steel strip and steel pipe are heated at the same time, so that they can be welded together. It has the characteristics of long life, wide temperature range and high pressure tolerance.
The serrations are small grooves or notches that are cut into the fin surface, which disrupt the boundary layer and increase the turbulence of the fluid flowing over the fins. This increased turbulence enhances the convective heat transfer between the tube and the fluid, resulting in a more efficient heat exchanger. Serrated finned tubes are commonly used in applications where high thermal performance is required, such as in boilers, air-cooled condensers, and other heat exchangers.
The production of high-frequency welded serrated finned tubes involves:
These tubes are essential in various industrial applications, including:
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.
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.
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.
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.
Typical finned tube configurations and dimensional references
| Type | Description | Base Tube O.D. (mm) |
Fin Specification (mm) | |||
|---|---|---|---|---|---|---|
| Fin Pitch | Fin Height | Fin Thickness | Remarks | |||
| Embedded | G-type fin tube | 16–63 | 2.1–5 | <17 | ~0.4 | High bond strength |
| Extruded | Single / bi-metal fin tube | 8–51 | 1.6–10 | <17 | 0.2–0.4 | Excellent corrosion resistance |
| Low fin / T-type fin tube | 10–38 | 0.6–2 | <1.6 | ~0.3 | Used in condensers | |
| Bamboo / corrugated tube | 16–51 | 8–30 | <2.5 | – | Enhanced turbulence | |
| Wound | L / KL / LL-type fin tube | 16–63 | 2.1–5 | <17 | ~0.4 | Aluminum fins on steel tube |
| String | String fin tube | 25–38 | 2.1–3.5 | <20 | 0.2–0.5 | Easy field cleaning |
| U-type | U-bend tube | 16–38 | – | – | – | For heat exchangers |
| Welded | HF welded fin tube | 16–219 | 3–25 | 5–30 | 0.8–3 | High-temperature service |
| H / HH-type fin tube | 25–63 | 8–30 | <200 | 1.5–3.5 | Boiler economizers | |
| Studded fin tube | 25–219 | 8–30 | 5–35 | φ5–20 | Radiant heating | |
Finned tubes are widely used in water-tube boilers, economizers, air preheaters and waste heat recovery units. Water or steam flows inside the tubes, while hot flue gas passes over the extended fin surfaces. The increased external surface area significantly improves heat transfer efficiency and reduces overall equipment size.
Typical selections: HF welded carbon steel fin tubes for economizers, H-type fin tubes for high-dust environments, and studded tubes for radiant sections. Material selection follows service temperature, flue gas chemistry and fouling considerations.
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Testing instrument
Hardness tester
Drawing Machine
Component analyzer
Aluminium KL finned tube
L LL KL G production line
Production equipments
Extrusion equipment
Fin tube bending
Ребристая труба для отопления на свинокомплексах и птицефабриках
Отопительные трубы с ребрами обеспечивают хорошую теплопередачу, благодаря абсолютно жесткой посадке плоского ребра на внутренней трубе. Наши отопительные трубы с ребрами применяются везде, где особые условия монтажа требуют использования необычных решений, например, в фасадных системах отопления, на многоярусных складах, в теплицах, при защите стеклянных куполов от запотевания и т.д., также трубы используются для отопления жилых, промышленных и складских помещений. Имеют документированную высокую степень теплоотдачи.
Ребристые трубы монтируются при помощи стандартных фитингов, либо под сварку по желанию Заказчика.
Мы изготавливаем два типоразмера ребристой трубы :
Ду32 и Ду40.
Длину трубы определяет Заказчик.
Покрытие трубы:
-грунт
-порошковая окраска
-горячий цинк.
По ценам и срокам изготовления вы можете узнать, позвонив по телефону
It is fabricated with a batch of single fins that were processed by the punch press and then manually or mechanically, with a certain distance (wingspan) on the base tube.
This is the earliest fin tube fabrication with low cost and simple production process/ technology, easy to maintain. Divides into manual set and mechanical set. Manual set uses a tool that relies on the power of man to press the fins one by one. This method is limited by the pressure of the fin, so it is easy to get loose. The machine – set fin is carried on the wing piece machine. Due to the mechanical impact or liquid pressure, the pressure of the fin is high, so it can be used in a larger volume. The bonding strength between fin and tube is high and not easy to loosen. Mechanical transmission has high productivity, but the noise is large, the safety is poor, and the working conditions of the workers are not good. Although the hydraulic transmission does not have the above problem, but the equipment price is more expensive, the technical requirement to use maintenance personnel is higher, its productivity is also lower.
Currently HF Fin Tube is one of the most widely used helical fin tubes, you can see it as waste heat recovery in power, metallurgy, concrete, oil and gas, petrochemical, etc. When winding the steel strip around steel tube, the use of high frequency current skin effect and proximity effect on steel strip and steel pipe surface heating, until the plastic state or melt, the coil steel belt must be under pressure to complete welding. Comparing with embedded type and spot welding spiral crimped type, it is more advanced either on fin tube quality or production efficiency or automation degree.
The extruded fin is formed from an outer aluminum tube with a large wall thickness (muff), which is aligned over an inner base tube. The two tubes are pushed through three arbors with rotating discs that literally squeeze or extrude the aluminum fins up and out of the muff material in a spiral shape in one operation. Comparing with welding fin tube, dr extruded fin has higher production efficiency with low cost on material and high heat transfer. At present, it divides into copper or aluminum single metal fin tube and bi-metal composited fin tube.
Fin tube manufacturers produce a wide range of fin tubes. They are used in heat exchangers (air, water and chemically cooled) for various industries such as petroleum, petrochemical, steel, power generation and many more.
Corrosion protection processes are performed during fin tube manufacturing and the material used is corrosion resistant. Some fin tube types are:
Helical high finned tubes are used to repair air-cooled heat exchangers and are available in 5 variations
| Type | Photo | Manufacturing Feature | Typical Properties |
|---|---|---|---|
| KL Fin |
|
Fin foot is knurled into a matching knurl on the base tube, enhancing mechanical bonding and thermal contact. |
Max Temp: 260 °C (500 °F) Corrosion Resistance: Fair Mechanical Strength: Fair Fin Material: Aluminium, Copper |
| G Fin |
|
Fin strip is wound into a pre-grooved tube and locked by cold-flow of the base tube material, ensuring a secure joint at elevated temperatures. |
Max Temp: 400 °C (750 °F) Corrosion Resistance: Poor Mechanical Strength: Fair Fin Material: Aluminium, Copper, Carbon Steel |
| LL Fin |
|
Similar to L fin, but with the fin foot overlapped to fully encapsulate the base tube, improving corrosion protection in aggressive atmospheres. |
Max Temp: 180 °C (355 °F) Corrosion Resistance: Fair Mechanical Strength: Poor Fin Material: Aluminium, Copper |
| L Fin |
|
Fin strip is tension-wound onto the base tube, providing uniform contact pressure and basic corrosion protection for the underlying tube. |
Max Temp: 150 °C (300 °F) Corrosion Resistance: Fair Mechanical Strength: Poor Fin Material: Aluminium, Copper |
| Extruded Fin |
|
Formed from bi-metallic tube by extruding aluminium outer layer into integral fins, providing excellent bond strength and full encapsulation of the base tube. |
Max Temp: 285 °C (545 °F) Corrosion Resistance: Excellent Mechanical Strength: Excellent Fin Material: Aluminium |
Fin foot is pre-formed into an LL shape (overlapped LL) and applied to base tube under tension.
However, foot is pre-shaped to give overlap of one foot onto another, thereby improving base tube protection and thermal contact area Fin materials: Aluminum Base tube materials: Any metallic material.
The smooth flat fins perpendicular to the tube surface give rise to very low resistance to air /gas flow and ensure that fouling is kept to a minimum. The foot of the fin is in contact with base tube and provides a complete sheathing over the finned length.
The Overlapped "L" fin design has interlocking fins that are wound together to prevent movement and separation. The fin protects the entire tubes, so the designation works well for the applications where corrosion is a factor.This type of finned tube is often used as an alternative to the more expensive extruded type fin in corrosive environments.
Fin tubes are a type of heat exchanger that is used in many different industries. These tubes have a finned surface, which increases their surface area and allows them to transfer heat more efficiently. This makes them ideal for applications where high heat transfer rates are required, such as in power plants and refrigeration systems.
Fin tubes are made from a variety of materials, including copper, aluminum, and stainless steel. They are available in a range of sizes and shapes and can be customized to meet the specific needs of each application.
One of the key benefits of fin tubes is their ability to operate efficiently at high temperatures and pressures. This makes them suitable for use in a wide range of applications, including air conditioning, heat exchangers, and radiators.
In addition to their high thermal performance, fin tubes are also durable and long-lasting. They are resistant to corrosion and can withstand the harsh environments often found in industrial settings. This makes them a cost-effective solution for many different industries.
Ceramic lined pipe is made through self-propagating high-temperature synthesis (SHS) technique.
Cast basalt lined steel pipe is composed by lined with cast basalt pipe, outside steel pipe and cement mortar filling between the two layers.
Ceramic tile lined pipes have very uniform coating of specially formulated ceramic material that is affixed to the inner of the pipe.
The material of the rare earth alloy wear-resistant pipe is ZG40CrMnMoNiSiRe, which is also the grade of rare earth alloy steel.
Tubes Erosion Shields are used to protect boiler tubing from the highly erosive effects of high temperatures and pressures thereby greatly extending tube life.
The ASTM A213 T91 seamless tubes are primarily used for boiler, superheater, and heat-exchanger.
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