ASME SA179 L-Type Fin Seamless Tube For air coolers,heat exchanger

What is L-type finned tubes?

• An L-type finned tube is a finned tube with an L-shaped cross-section. Its feature is that fins are installed on one or both sides of the pipe to enhance heat transfer. The fins are usually made of aluminum or copper and are continuously spirally wound around the outer surface of the base pipe under tension.

What is manufacturing process of L-type finned tubes?

Material Selection

• Base Tube Material:Commonly used materials include carbon steel, stainless steel, and copper. The choice of material depends on the specific application requirements, such as thermal conductivity, mechanical strength, and corrosion resistance.
• Fin Material:Typically, aluminum or copper is used for the fins due to their excellent thermal conductivity and corrosion resistance

Fin Preparation

• Shaping: The fin material is shaped into an L-shape using precision machinery. This L-shape is crucial for the mechanical bonding and heat transfer performance.

Winding Process

• Winding: The L-shaped fins are helically wound around the base tube under tension. This process ensures a tight fit and uniform spacing of the fins along the length of the tube
• Tension Control: Advanced numerical control (CNC) machines are used to maintain the optimal tension during winding, ensuring that the fins are securely attached to the base tube.

Tube Surface Preparation

• Knurling: The base tube is knurled to create a textured surface. This increases the contact area between the fin and the tube, enhancing the mechanical bond and heat transfer efficiency

Fin Attachment

• Mechanical Bonding: The foot of the L-shaped fin is securely knurled into the grooves of the base tube. This mechanical bonding process ensures a strong and durable connection, which is essential for high-performance heat transfer.
• End Fixation: The fins are attached at both ends to prevent unwinding, ensuring the structural integrity of the finned tube.

Quality Control

• Dimensional Accuracy: The finned tubes are checked for dimensional accuracy, including fin spacing, fin height, and tube diameter. Tolerances are typically ±0.5mm for fin spacing and ±0.5% for tube diameter.
• Surface Finish: The surface of the finned tube is inspected for smoothness and the absence of defects such as oxide scale or rust. Appropriate surface treatments, such as coating or galvanizing, are applied to enhance corrosion resistance.

Testing and Inspection

• Pull-Off Test: A pull-off test is conducted to ensure the bonding strength between the fin and the tube. The pull-off force should be greater than 200 MPa or result in the tearing of the tube material.
• Bending and Hammering Tests: The fins are subjected to bending and hammering tests to ensure their mechanical stability and resistance to deformation.

Final Assembly and Packaging

• Assembly: The finished finned tubes are assembled into the final heat exchanger or cooling system components.
• Packaging: The finned tubes are carefully packaged to prevent damage during transportation and storage.

Chemical Composition:

Mechanical Properties:

In which areas are L-type finned tubes applied?

• Power Generation: Air coolers and air heaters.
• Petrochemical: Heat exchangers and air coolers.
• Paper Industry: Air coolers and air heaters.
• Tobacco Industry: Air coolers and air heaters.
• Building Heating: Air heaters.
• Food Industry: Air heaters for spray drying systems of plant protein powder, starch, etc.

What is advantages of L-type finned tubes?

• Easy to manufacture and cost-effective.
• High heat transfer efficiency with a high fin ratio.
• Protects the base pipe from air erosion.