The Difference Between L-fin Tubes and KL-fin Tubes

Datang is the professional of the technical specifications for L-fin tubes and KL-fin tubes:

The KL type solves the contact thermal resistance and high temperature loosening problems of the L type through the base tube knurling and double fin design, achieving higher heat transfer efficiency and structural stability

‌Core Features of L-Fin Tubes‌

1. ‌Structure & Manufacturing‌

   • ‌Mechanical Wrapping‌: Metal strips (steel/aluminum) are cold-spiraled onto base tubes via mechanical force, forming L-shaped crimped roots at the fin base.
   • ‌Knurled Design‌: Surface knurling enhances airflow turbulence, improving thermal efficiency (heat dissipation area ‌3–5× larger‌ than bare tubes).

2. ‌Performance Parameters‌

   • ‌Material Compatibility‌: Carbon/stainless steel base tubes (Φ50–89 mm); aluminum strips (thickness: 0.2–0.5 mm) typically used for fins.
   • ‌Temperature Tolerance‌: Aluminum fins ≤70°C; steel fins ≤350°C.
   • ‌Precision Control‌: Fin height tolerance ±0.5 mm; fin spacing adjustable (2.3–8 mm; min. spacing ≥2.3 mm).

3. ‌Limitations & Improvements‌

   • Higher contact thermal resistance; prone to loosening at elevated temperatures (aluminum fin bond strength degrades >70°C);
   • Corrosion protection relies on surface treatments (painting or hot-dip galvanizing; electroplating obsolete).

‌KL-Fin Tubes Technical Features‌

1. ‌Structural Innovation‌

   • ‌Double L-Fin Design‌: Dual-layer aluminum strips form an LL-shaped structure, enhancing rigidity and bond stability.
   • ‌Tight Fin Spacing‌: Minimum spacing of ‌2.3 mm‌ increases heat transfer area per unit length by ‌30%‌ vs. standard L-fins.

2. ‌Performance Advantages‌

   • ‌Anti-Collapse‌: Dual-fin configuration reinforces mechanical strength, resisting deformation during transport/high-velocity airflow.
   • ‌Media Compatibility‌: Preferred for stable fluids (hot water/coolant); limited suitability for steam/thermal oil applications.

‌Industrial Applications Comparison‌

‌Selection Guidelines‌

1. ‌Prioritize KL-Fin Tubes when‌:
   • Requiring fin spacing ≤3 mm for high-efficiency heat transfer;
   • Operating in clean environments with temperature fluctuations <50°C (avoids fouling).
2. ‌Avoid L-Fin Tubes when‌:
   • Handling steam (>150°C loosens fins);
   • Exposed to highly corrosive flue gas (requires additional coatings).

‌Industry Trend‌: High-frequency welding progressively replaces traditional wrapped L-fin tubes to eliminate contact thermal resistance.