Lord Fin Tube-Finned Tube Manufacturer in China

2019-09-08Leave a message

Finned Tube Overview

Finned tubes are crucial heat exchange elements, primarily utilized in air-cooled exchangers to compensate for the low air-side heat transfer coefficient. In order to enhance heat exchange efficiency, fins are added to the outer or inner surfaces of heat exchange tubes, significantly increasing the surface area. This improvement in surface area results in enhanced heat exchange efficiency.

Finned Tube Manufacturer in China

As a leading finned tube manufacturer in China, we specialize in producing a wide range of finned tubes designed to improve heat exchange efficiency. Our products include high-frequency welding spiral finned tubes and other advanced finned tube types, catering to various industrial applications.

Finned Tube Main Catalog

1. Main Performance Requirements of Finned Tubes

2. Fin Tube Production Technology Status

3. Classification of Finned Tubes

Main Performance Requirements of Finned Tubes

As a heat exchange component, finned tubes operate under extreme conditions, such as high temperature and corrosive atmospheres, especially in applications like boiler heat exchangers. The performance requirements include:

1. Anti-Corrosion Performance

2. Wear Resistance (Anti-Wear)

3. Low Heat Contact Resistance

4. High Stability Heat Transfer Capacity

5. Anti-Ashing Ability

Current Status of Fin Tube Production Technology

1. Plate Fin Tube:

Stamped fins can be manufactured in various shapes and sizes, commonly referred to as "Square Fin" or "Plate Fin". The production process involves punching individual fins and placing them on the tubes surface manually or mechanically.

The finned tube process is to pre-process a batch of individual fins by punching, and then manually or mechanically, according to a certain height (wing distance), the fins are placed on the outer surface of the tube by interference. It is the earliest method of processing finned tubes. Due to the simple process and low technical requirements, the equipment used is inexpensive and easy to maintain, so many factories are still in use. This process is a labor-intensive process solution suitable for the capital and technical conditions of small or medium-sized enterprises.

The manual method is called a manual suit. It uses tools to rely on human strength to push the fins one by one. In this method, since the pressing force of the fin is limited, the interference of the set is small, and the fin is prone to looseness.

The mechanical set fins are made on a fin set machine. Since the fin press-in is caused by mechanical impact or liquid pressure, the press-in force is large, so that a large interference can be used. The joint strength between the fin and the tube is high and it is not easy to loosen. The mechanical transmission set machine has high productivity, but the noise is high, the safety is poor, and the labor conditions of the workers are not good. Although the above problems are not present in the hydraulic transmission, the equipment is more expensive, the technical requirements for the maintenance personnel are higher, and the productivity is lower.

2. Embedded Spiral Fin Tube:

This process involves machining a spiral groove on the steel pipe and embedding the steel strip into the groove. The strip is welded at both ends to prevent rebounding.During the winding process, due to a certain pre-tightening force, the steel strip will be tightly placed in the spiral groove, thereby ensuring a certain contact area between the steel strip and the steel tube. In order to prevent the steel strip from rebounding, both ends of the steel strip are welded to the steel pipe. In order to facilitate the setting, there should be a certain backlash between the steel strip and the spiral groove. If the backlash is too small and an interference is formed, the inlaying process is difficult to proceed smoothly. In addition, the entangled steel strip always has a certain rebound, which results in a poor joint between the steel strip and the spiral groove bottom surface. Inlaid fins can be carried out on general-purpose equipment at a low cost, but the process is complicated and the production efficiency is low.

3. Brazed Spiral Fin Tube:

Used for metal temperatures up to 380°C (800°C with special coating), this method involves winding a steel strip around the tube and brazing the gap between the strip and the tube.

The processing of the brazed spiral finned tube is carried out in two steps. Firstly, the steel strip plane is wound on the outer surface of the pipe in a spiral manner perpendicular to the axis of the pipe, and the two ends of the steel strip are welded to the steel pipe for fixing, and then the gap between the steel strip and the steel pipe is eliminated, and the brazing method is used. The steel strip and the steel tube are welded together.

Because of its high cost, this method is often used in another way, in which the tube wrapped with steel strip is placed in a zinc bath for integral hot-dip galvanizing instead. The use of integral hot-dip galvanizing, although the plating solution does not see a good gap between the fin and the steel pipe, but a complete galvanized layer is formed on the outer surface of the fin and the outer surface of the steel pipe. The spiral finned tube with integral hot-dip galvanizing is limited by the thickness of the galvanized layer (when the galvanized layer is thick, the zinc layer is weak and easy to fall off), and the zinc liquid cannot penetrate into the gap completely, so the fins and The joint rate of steel pipes is still not high. In addition, the heat transfer coefficient of zinc is smaller than that of steel (about 78% of steel), so the heat transfer capacity is low. Zinc is highly susceptible to corrosion in acids, alkalis and sulfides. Therefore, galvanized spiral finned tubes are not suitable for the production of air preheaters (recovery of boiler flue gas waste heat).

4. High-Frequency Welding Spiral Fin Tube:

Utilizing high-frequency current to heat and weld the steel strip to the steel pipe, this method is highly efficient and widely used in waste heat recovery applications.

The skin effect and the proximity effect of the high-frequency current are used to heat the outer surface of the steel strip and the steel pipe until plastic state or melting, and the welding is completed under a certain pressure of winding the steel strip. This high frequency welding is a solid phase welding. Compared with inlaying, brazing (or integral hot-dip galvanizing), it is more advanced in terms of product quality (high fin weldability, up to 95%), productivity and automation.

High-frequency welding finned tube manufacturing

5. Three-Roller Cross-Rolling Integral Spiral Fin Tube:

This method uses a mandrel and roller blades to form fins on the outer surface of a seamless steel pipe, resulting in high heat transfer efficiency.

The production principle of the three-roller-rolled monolithic spiral finned tube is as follows: a mandrel is lined in the light pipe, and the seamless steel pipe is processed on the outer surface of the cavity formed by the groove and the core through the rotation of the roll blade. Finned. The finned tube produced by this method has an organic whole due to the base tube and the outer fin, so there is no problem of contact thermal resistance loss, and the heat transfer efficiency is high. Compared with the welding method, the three-roll cross-rolling method has the advantages of high production efficiency, low consumption of raw materials, and high heat exchange rate of the produced finned tubes.

At present, the three-roller-rolled monolithic spiral finned tube technology has been successfully applied to single-fin tube or composite finned tube with copper or aluminum fins, or steel low-fin tube; steel integral finned tube is currently The market is often seen as a low-fin tube, and the overall high-fin tube is made of aluminum or copper, which is usually cold-rolled

6. Laser Welded Finned Tubes:

Emerging in China, this technology offers zero contact thermal resistance, compact assembly, and higher energy efficiency, meeting national emission standards.

Laser welded finned tubes are used in civil fireplaces, industrial boilers, etc., using German technology, domestically emerging, but in Europe for more than a decade, the advantage is that the contact thermal resistance is zero, compared with high-frequency welding winged Larger, lighter weight, assembled heat exchangers are compact, more energy efficient and environmentally friendly, meeting national emission requirements.

How to Classify of Finned Tubes?

1. By Processing Technology

- Extruded Fin Tube

- Welded Molded Fin Tube (High-Frequency Welded, Submerged Arc Welded)

- Roll Formed Fin Tube

- Plate Finned Tubes

- Cast Iron Finned Tubes

- Tension Wrapped Fin Tube

- Embedded Finned Tube

2. By Fin Shape

- Square Finned Tube

- Round Finned Tube