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Finned Tube

Serrated Finned Tube

Serated spiral high frequency welding fin tube High frequency welding spiral fin tube is a new kind of heat transfer material which has the feature of wearing resistance and high efficient. And it is a kind of high efficiency and energy saving heat transfer element. It adopts high frequency......
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Serated spiral high frequency welding fin tube

High frequency welding spiral fin tube is a new kind of heat transfer material which has the feature of wearing resistance and high efficient. And it is a kind of high efficiency and energy saving heat transfer element.

 

It adopts high frequency welding spiral technology, the national patent technology with high frequency power supplies as the heat source to heat the steel strip, steel pipe at the same time, yo make its welded together as a whole. This technology has the characteristics as high in thermal efficiency, large heat dissipation area, long service life, range adaptation temperature, high pressure, etc.

 

Widely used in waste heat recovery, petrochemical industry, power plant boiler, economizer, coaches, civil building heating, refrigerating, drying, medicine of wood drying, food drying system and other industries.


The advantages of high frequency welding spiral fin tube:

1. The simple and economic installation

The maximum length of high frequency welding spiral finned tube can reach 6 meters, that reduces the join points, making the installation more economic, efficient, and also reduces the leakage probability of joints.

2. Easy maintenance

After installation, high frequency welding spiral fin tube needs no longer to be maintained.

3. High efficiency

The heat dissipation area of high frequency welding spiral fin tube is more than 8 times of the light tube.The internal is smooth, so the internal flow resistance is small.

4. Long service life

Fin and pipes with high mechanical strength, so the tensile strength is more than 200 mpa. Both inside and outside of the tube are all made of hot dip galvanized processing.

Weldable fin material: carbon steel, stainless steel, alloy steel, corrosion resistant steel.

 

Spiral fin tubes with serrated fin are major components of economizers, heat recovery boilers and many other industrial heat exchanger applications. They are available with solid/plain or serrated fins. All finned tube configurations are tailored to the customers’ specific requirements and flue gas characteristics: serrated fins are mainly used for clean applications such as natural gas firing and solid fins where dusty or abrasive conditions exist.

 

High-frequency welding finned tube is divided into two types:

Solid type and Serrated type. The weld strength of the fins on the tube is more than 90% of the fin thickness. High Frequency Resistance Welded Fin Tubes is widely used in the recovery of waste heat from boiler flue gas.

Backed by years of industry experience, we are engaged in offering a premium quality range of Fin tubes.

Can be used for practically any heat transfer application, and is particularly suited to high temperature, high pressure applications with high fin-side temperatures. In general, the serrated fin configuration is said to transfer heat more efficiently than solid fin since the serrated fin segments allow some lateral (cross-fin) flow of fluid along the tube axis, which serves to increase turbulence, thereby breaking up the thermal boundary layer and increasing heat transfer efficiency.

 

Manufacturing process

The fin strip is welded continuously and spirally wound onto a polished bare tube. And the tube and fins are bonded together by using high frequency resistance welding technique.

 

Applications:

The HFW Finned Tubes find the preference in the following industrial sectors:

1. Fired heaters; 2. Heat exchangers; 3. Boilers; 4. Economizers;5. Pre-heaters;6. Coolers;7. Heat pipes; 8. Heaters.

 

Base tube diameter         16mm-273mm

Base tube wall thickness          2.0mm-15.0mm

Fin thickness    0.5mm-3.0mm

Fin pitch   3.0mm-30.0mm

Fin height          8.0mm-35.0mm

Base tube material: Stainless steel, Carbon steel, Alloy, Nickel etc.

Fin material: Carbon steel, Stainless steel, Alloy etc.

 

High frequency welded spiral finned tube is one of the most widely used finned tubes. It is a plain type fin, made by helically winding the fin strip on edge around the tube. The fin is continuously welded to the tube by a high frequency electrical resistance welding process which leaves the tube essentially unchanged metallurgically. The width of the weld is always greater than 90 percent of the thickness of the fin, assuring a strong bond between the fin and the tube for efficient heat transfer and long life. Solid fins are preferred in fouling applications. The finished finned tube is extremely strong mechanically and has greater resistance to bursting pressure than the bare tube due to the reinforcing effect of the fin. Because of its excellent strength and resistance to deformation, this tubes are well suited for applications where severe abuse is expected in service.

Our Welded Helical finned tubes consist of steel fins wrapped helically around steel pipe, and continuously welded using the GMAW process.  The fins may be either solid or serrated.

For Welded Helical Solid and Welded Helical Serrated finned tubes, the fin and tube materials can be any combination that can be welded together using the GMAW (gas-metal-arc-welding) process.

For Welded Longitudinal finned tubes, the fin and tube materials can be any combination that can be resistance welded together.

 

What Type of Fin Should I Use?

The choice between Aluminum L-foot and the welded finned tubes (helical and longitudinal) is usually clear -- aluminum L-foot finned tubes are generally used in air-cooled applications with service temperatures below 400 degrees F.  Within the aluminum L-foot category, the choice between solid fin and perforated fin is less clear, and depends upon whether you want to take advantage of the improved heat transfer efficiency claimed for perforated fin.

Within the welded fin types, our experience with customers indicates that the choice between helical fins and longitudinal fins generally depends on the direction of fluid flow across the fins, with the objective of having the fluid pass between the fins, rather than across the fins.  For example, in the case of a tank heater, fluid flow is caused by convection currents within the tank -- as the fluid next to the finned tube is heated, it rises vertically, and the colder fluid near the top of the tank drops vertically.  Therefore if a tank heater is to be installed with the finned tubes oriented vertically, Longitudinal Finned Tube may be the best choice, since the rising fluid will pass in a direction parallel to the longitudinal axis of the tube, and between the fins.  However if the heater is to be installed horizontally, helical fins may be the best choice, since the fluid flow would be perpendicular to the axis of the tube, and between the helical fins.


If the choice is for welded helical finned tubes, a further decision is required -- Helical Solid or Helical Serrated? ...

- For some tube/fin configurations, helical serrated gives greater surface area than solid, and for other tube/fin configurations the reverse is true.  A comparison of surface area may be made by using the tables included in Design Info.

- A definite advantage of helical serrated is that for a given pipe size, a greater fin height can be used for serrated than for solid.  This is because the serrations, or cuts, in the fin strip allow a greater fin strip width to be formed around a given size tube without significant deformation of the fin.

- It has been claimed that helical serrated offers an advantage over helical solid, particularly for lighter fluids, in that the serrated segments allow some lateral (cross-fin) flow of fluid along the tube axis, which serves to increase turbulence, thereby breaking up the thermal boundary layer and increasing heat transfer efficiency; and also slows the formation of fouling deposits between fins.

The decision which type of fin to use is yours -- Metalli stands ready to provide any type of finned tube you need.

 

Why Use Finned Tubes?

Finned tubes are used in applications involving the transfer of heat from a hot fluid to a colder fluid through a tube wall.  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.  In the case of a bare (unfinned) tube, where the outside surface area is not significantly greater than the inside surface area, 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 (for example steam inside and oil outside), the overall heat transfer rate can be greatly improved by increasing the outside surface area of the tube.  In mathematical terms, the product of heat transfer coefficient for the outside fluid multiplied by outside surface area is made to more closely match the  product of the inside fluid heat transfer coefficient multiplied by tube inside surface area.

So the whole concept of finned tubes is to increase outside surface area.  As an example, a common finned tube configuration of 2" (nominal) pipe with 3/4" high welded helical solid fins of 12 gauge thickness with 6 fins per inch has an outside surface area of 8.23 sq. ft. per linear foot; whereas the same bare pipe has an outside surface area of only 0.62 sq. ft. per linear foot.  (See Design Info for extensive tables of surface areas and fin weights.)

The advantage of finned tubes is that by increasing overall heat transfer rate, the total number of tubes required for a given application is reduced, thereby also reducing overall equipment size and decreasing 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.

 

What Materials Are Used for Finned Tubes?

For Aluminum L-Foot finned tubes, the fin material is aluminum, either 1100-0 or 5005.  The tube material is generally carbon steel, stainless steel, or brass; however the tube can be of any material.

For Welded Helical Solid and Welded Helical Serrated finned tubes, the fin and tube materials can be any combination that can be welded together using the GMAW (gas-metal-arc-welding) process.

For Welded Longitudinal finned tubes, the fin and tube materials can be any combination that can be resistance welded together.

The materials chosen for a given application are a function of service temperature, corrosive environment, and/or erosive environment.  Common tube materials used for our welded product lines include: carbon steel, carbon moly, chrome moly, stainless steel, Inconel, and Incoloy.  Common fin materials include: carbon steel; stainless steels of types 304, 310, 316, 321, 409, and 410; Nickel 200, and Inconel.

 

High Frequency Welding Serrated Fin Tube

TS offers the widest variety of sizes available in the industry. All of our products are domestically sourced, developed, and produced, which means our customers have immediate access to exactly the products they need for their particular application. And you are assured of the highest quality and manufacturing standards and a local, concerned, customer service presence.

The strong connection between fin and base tube prevents loosening of fin because of heat stress, oxidization, corrosion etc., use at very high temperatures possible. This welded steel finned tubes configuration can be used in practically any heat transfer applications, and particularly suited for high temperature, high pressure applications. The important features of this configuration are efficient, effective bond of fin to tube under any conditions of temperature and pressure, and ability to withstand high fin-side temperatures.

These tubes are used with a wide range of material such as carbon steel, low alloys steel and stainless steel for corrosive flue gas or high temperatures. The finned tube can supply these tubes shaped in hairpin, with extremities bevelled.

As the fin strip is formed around the tube its outer (serrated) edge spreads, opening the segments like petals of a daisy. A continuous weld is applied at the point where the fin strip first begins to bend around the tube diameter using Vulcan’s unique gas metal arc welding process. This welding process creates the strongest fin to tube attachment in the industry, excellent heat transfer characteristics, low fin-side pressure drop and little to no change in grain micro structure and physical characteristics even when 3%-9% chromium tubes are used. For a given pipe or tube size, the desired heat transfer surface area per unit length of tube can be obtained by specifying the appropriate fin height and/or number of fins per inch of length. The following table shows Vulcan’s manufacturing capabilities for helical serrated finned tube:

Tube/Pipe Size  1.00″ to 15.75″ OD, Fin Height: 0.3mm to 49.50mm

Fin Segment Width: 5/32″or 5/16″,Fin Thickness: 0.8 mm ~ 4.0 mm, Fin Pitch: 1 to 20 fins per inch

Materials: Carbon Steel, Alloy Steel, Stainless Steel and Corrosion-resistance Steel.

Application: Heat Transfer Equipment including Heat Exchangers, Boilers, Economizers, Super Heaters, Fired Heaters, HRSG, Waste Heat Recovery Systems etc.

Services   In addition to finning and tube bending we offer tubing, pipe, cutting, beveling, return bends, elbows, crating, freight and economizer consulting.

In general, the fin configuration is said to transfer heat more efficiently than solid fin since the serrated fin segments allow some lateral (cross-fin) flow of fluid along the tube axis, which serves to increase turbulence, thereby breaking up the thermal boundary layer and increasing heat transfer efficiency.

 

As per type “WOS” but fins are serrated. Advantages Higher heat coefficient. For the same pressure drop compared with “WO” fin.

 

Serrated Finned tube Used in boilers, furnaces and fired heaters for efficient heat recovery.

A continuous helical fin is attached to the base tube by high frequency electric resistance welding in order to give an efficient and thermally reliable bond. Fins can be either solid or serrated (segmented).

TUBE AND PIPE SIZES AVAILABLE:

Tube OD: 25.4 / 31.8 / 38.1 / 50.8 / 63.5 and 76.0 mm

Pipe OD: 26.7 / 33.4 / 42.2 / 48.3 / 60.3 / 73.0 / 88.9 / 101.6 / 114.3 / 141.3 / 168.3 and 219.1 mm

TUBE/PIPE THICKNESS:

Minimum 2.13mm for solid fin, Minimum 1.9mm for serrated fin, Minimum thickness is also dependent on the fin thickness and tube/pipe OD.

FIN HEIGHT RANGE: Solid Fin: 6.3mm - 31.8mm; Serrated Fin: 12.7mm - 38.1mm

 

Fin Height is dependent on the fin type (solid or serrated) tube OD, fin thickness and material.

Fin Thickness is dependent on the fin material, height of fin and tube OD. usually between 1.0mm and 3.4mm.

 

Fin Density is dependent upon fin type (solid or serrated) tube OD, fin height, fin thickness and fin material. Density is generally between 1 fin/inch and 7 fins/inch.

 

Materials for both tube/pipe and fin can be a combination of carbon steel, low alloy steel and stainless steel.


FOR A RAPID QUOTATION PLEASE SPECIFY:

Number of pieces, Pipe/tube: Diameter, thickness, length and material specification. Fins: material specification, type (solid or serrated), height, thickness, spacing, finned length and unfinned sections. Weld prep details if required. Delivery period required.

 

Welded Helical Serrated Finned Tubes are produced in the same manner as solid fin, except that before the fin strip is formed around the tube, the fin strip is cut (or “serrated”) crosswise from one edge (which will become the outer edge of the fin segments) to within 1/4″ of the other edge, leaving an uncut portion that will become a continuous base for the fin segments.  The interval between cuts (which determines the segment width after the strip is formed around the tube) may be specified as either 5/32″ or 5/16″.   After being cut, the fin strip is held under tension and confined laterally as it is formed around the tube, thereby ensuring forceful contact with the tube surface.  As the fin strip is formed around the tube its outer (serrated) edge spreads, opening the segments like petals of a daisy. A continuous weld is applied at the point where the fin strip first begins to bend around the tube diameter using gas metal arc welding (GMAW) process. This welding process creates the strongest fin to tube attachment in the industry, excellent heat transfer characteristics, low fin-side pressure drop and little to no change in grain microstructure and physical characteristics even when 3%-9% chromium tubes are used.

 

This serrated fin configuration can be used for practically any heat transfer application, and is particularly suited to high temperature, high pressure applications with high fin-side temperatures. In general, the serrated fin configuration is said to transfer heat more efficiently than solid fin since the serrated fin segments allow some lateral (cross-fin) flow of fluid along the tube axis, which serves to increase turbulence, thereby breaking up the thermal boundary layer and increasing heat transfer efficiency.


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