Finned Tubes and their applications
Finned tubes are commonly used in applications where heat needs to be transferred from a hot fluid to a cooler one across the tube wall. The rate at which heat is transferred depends on several factors, such as the temperature difference between the two fluids, the heat transfer capacity of the fluids and the tube wall, and the surface area exposed for heat exchange.
Table of contents
- What is finned tube?
- Different types of finned tubes
- Why Finned Tubes are made of Aluminum?
- Finned tube heat exchanger working principle
- Low fin tubes dimension
- Uses Of Helical solid finned tubes
- Advantages of Using Fin and tube heat exchangers
- G Type Finned Tube Features
- Quality Control for Stainless steel finned tube
- Size Range Of G Type Fin Tube
- Classification of Finned tubes based on process and fin shape
- High fin tubes Vs Low fin tubes
- What can Cause Leakages in Low Fin Tubes?
- What Affects the Heat Transfer in a Low Fin Tube?
What is finned tube?
Finned tubes are elongated tubes with small fins attached to their outer surface, acting as heat exchangers. These fins enhance the heat transfer process by increasing the surface area, allowing heat to flow more efficiently between the inside and outside of the tube. They are essential components in heat exchangers and are used to transfer heat between thermally efficient fluids that carry heat effectively.
View different types of fin tubes for heat exchangers
The table below provides an overview of the main types of fin tubes used in heat exchangers. It will help you choose the right type for your specific application and understand the functions it is best suited for.
Different types of finned tubes
| Fin Type | Icon | Tube Material | Fin Material | Fin Height | Fin Thickness | Tube Diameter |
|---|---|---|---|---|---|---|
| Plain Finned |  |
Carbon steel, stainless steel, copper, aluminum | Aluminum, copper, stainless steel | 6-25 mm | 0.2-0.6 mm | 12.7 mm (1/2") to 63.5 mm (2.5") |
| L-Finned |  |
Carbon steel, stainless steel, copper | Aluminum, copper, stainless steel | 6-19 mm | 0.3-0.5 mm | 15.9 mm (5/8") to 38.1 mm (1.5") |
| G-Finned |  |
Carbon steel, stainless steel, alloy steel | Aluminum, copper | 6-15 mm | 0.3-0.5 mm | 15.9 mm (5/8") to 50.8 mm (2") |
| Extruded Finned |  |
Aluminum, copper | Aluminum | 8-16 mm | 0.4-1.2 mm | 12.7 mm (1/2") to 31.8 mm (1.25") |
| U-Tube Finned |  |
Carbon steel, stainless steel, alloy steel | Aluminum, copper, stainless steel | 6-25 mm | 0.3-0.5 mm | 15.9 mm (5/8") to 38.1 mm (1.5") |
| Studded Finned |  |
Carbon steel, stainless steel, alloy steel | Carbon steel, alloy steel | 10-50 mm | 6-12 mm | 25.4 mm (1") to 114.3 mm (4.5") |
| Helical Finned |  |
Carbon steel, stainless steel, copper, aluminum | Aluminum, copper, stainless steel | 8-16 mm | 0.3-0.5 mm | 12.7 mm (1/2") to 76.2 mm (3") |
Refer sizes and uses of finned aluminum tubing
Finned aluminum tubing is widely used in refrigeration systems, air conditioning, and industrial processes that require heating or cooling. Its high heat transfer capacity and durability make it a preferred choice over other types of heat exchangers.
Why Finned Tubes are made of Aluminum?
Aluminum finned tubes typically range in size from 3/8" to 1 1/2".
Aluminum is popular for manufacturing finned tubes due to its key properties:
- Excellent thermal conductivity
- Lightweight
- Corrosion resistance
- Ductility and malleability
- Cost-effective
Finned tube heat exchanger working principle
Finned tube heat exchangers are primarily used to transfer heat between two fluids through the tubes. The fins significantly improve the efficiency of the heat transfer process.
Low fin tube has a fin of about 1/16th in height
A low fin tube is a standard tube with a small fin, approximately 1/16th of an inch in height. The fin is integrated into the tube wall and is commonly used in liquid-to-liquid or liquid-to-gas applications such as coolers, chillers, and condensers.
Low fin tubes dimension
| Description | Size dimension |
|---|---|
| Tube Outside Diameter | Min. 12.7mm / Max. 31.75mm |
| Tube thickness (plain section) | Min. 1.245mm / Max. 3.404mm |
| Fin pitch | 19 – 26 – 27 – 28 – 30 – 36 fins per inch |
| Fin height | Max. 1,40mm |
| Tube length | Max. 25000mm |
Welded Helical solid finned tubes widely used in petrochemical industry
These tubes offer excellent resistance to corrosion, high pressure, and extreme temperatures, making them ideal for use in the petrochemical industry and industrial boilers. They are also used to heat, cool, or recover heat from industrial exhaust systems.
Uses Of Helical solid finned tubes
- Petrochemical industries
- Natural gas processing
- Blast furnace and converter system
- Power generation
- Waste incinerators
- Air conditioning
- Compressor coolers
Advantages of Using Fin and tube heat exchangers
- Increases heat transfer rate
- Improves heat transfer coefficient
- Reduces equipment size
- Enhances cost efficiency
- Expands the external surface area
G Type Finned Tube Features
- High fin stability
- Superior heat transfer efficiency
- High operating temperature capability
- Strong temperature resistance
- Excellent thermal shock resistance
Quality Control for Stainless steel finned tube
- Chemical composition analysis
- Dimensional inspection
- Flatten test
- Non-destructive testing
- Hydrostatic test
- Mechanical property testing
- Expansion test
- Surface quality check
Size Range Of G Type Fin Tube
| Base Tube Specification | Fin Specification | |||
|---|---|---|---|---|
| Outside Diameter (mm) | Wall Thickness (mm) | Height (mm) | Thickness (mm) | Pitch (mm) |
| 15.88-50.8 | 1.0-3.0 | 6.35-25.4 | 0.4 | 2.1-6.0 |
| Material | Material | Length | ||
| SS, CS, Alloy Steel, Copper | CS, Aluminum, Copper | ≤ 15m | ||
Classification of Finned tubes based on process and fin shape
| Tube Outside Diameter | Fin Thickness | Fin Height | Fins per Pitch |
|---|---|---|---|
| 5/8 | .015 / .016/ .020 | 3/8,1/2 | 6, 7, 8, 9, 10, 11, 12 |
| 3/4 | 5/8,1/2 | ||
| 1 | 5/8,1/2 | ||
| 1 1/4 | 5/8,1/2 | ||
| 1 1/2 | 5/8,1/2 |
Finned tubes generally use air to cool or heat fluids such as water
Finned tubes significantly increase the surface area of the tube, leading to more effective heat transfer with air. Using air for heating or cooling is beneficial because it is readily available, cost-effective, and eliminates the need for complex heating equipment or labor-intensive operations.
High fin tubes Vs Low fin tubes
| Features | High Fin Tubes | Low Fin Tubes |
|---|---|---|
| Fin Density | It has higher fin density | It has low fin density |
| Heat Transfer Efficiency | Due to higher fin density it provides superior heat transfer efficiency | It exhibits lower heat transfer efficiency compared to High Finned Tubes |
| Surface Area-to-Volume Ratio | Surface area-to-volume ratio is high due to fin density | Surface area-to-volume ratio is low due to modest fin density |
| Maintenance and Cleaning | Requires more maintenance and cleaning due to closely spaced fins | With more spaced-out fins, low maintenance is required compared to high fin tubes |
| Cost Considerations | It is costly due to complex manufacturing processes and materials | Low finned tubes are cost-effective |
What can Cause Leakages in Low Fin Tubes?
- Scale buildup: This narrows the inner diameter of the tube, leading to pressure build-up and eventual leakage.
- Thermal shock: Rapid temperature changes in the tube can cause cracks or ruptures.
- Improper installation: Proper installation and regular maintenance can prevent leakage.
- Tube corrosion: Corrosion increases the risk of leakage.
What Affects the Heat Transfer in a Low Fin Tube?
Several factors influence the effectiveness and efficiency of heat transfer in these tubes:
- Fluid properties
- Fin arrangement
- Number of fins
- Dimensions of the fins
- Surface finish
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