Low Heat Transfer Efficiency? — H and L Fin Tubes Combine to Boost Surface Area by 30%

In many heat exchangers and boiler economizers, low heat transfer efficiency often results from insufficient effective surface area and poor contact between fins and base tubes. Over time, this leads to higher fuel consumption, reduced system performance, and frequent maintenance. To overcome these limitations, Zhongyue Metallurgy integrates the structural advantages of H-type welded fin tubes (H Fin / HH Fin Tube) and L-type fin tubes (including perforated and wheel-type L fins) to significantly increase the heat exchange surface area and improve overall system efficiency.

The H-type finned tube features flat, rectangular fins welded directly to the base tube using full-penetration welding technology. This process ensures high mechanical bonding strength and excellent thermal conductivity. The H-shaped design expands the heat exchange area on both sides of the tube, improving heat transfer by up to 20–30% compared with traditional spiral fin designs. Its in-line configuration allows gases to pass evenly between the fins, minimizing turbulence loss while maintaining uniform temperature distribution—ideal for high-pressure boilers, economizers, and waste heat recovery systems.

Complementing the H-type structure, the L-type fin tube uses a helical wrapping or wheel-like fin arrangement that further enlarges the external surface. The perforated L fin design introduces microturbulence in the airflow, disrupting laminar layers and improving heat dissipation. When combined with the H-type geometry, the mixed-fin configuration maximizes contact area while enhancing convective heat transfer on both sides of the tube. This hybrid approach yields an overall 30% increase in effective surface area, resulting in faster heat exchange and improved thermal uniformity.

All fin tubes are available in carbon steel, alloy steel, or stainless steel materials such as A106, A179, 20G, TP304, and TP316L. Fin dimensions are customizable, with thicknesses ranging from 1.5–3.5 mm, pitch spacing down to 10 mm, and tube lengths up to 18 meters. Zhongyue’s advanced finning machines ensure precise welding, tight tolerances, and consistent geometry across every production batch.

To further enhance performance, the tubes undergo surface treatment with red oxide zinc phosphate primer externally and VCI (volatile corrosion inhibitor) protection internally, ensuring long-term corrosion resistance even under humid or acidic gas conditions.

By combining the efficiency of H-type welded fins with the aerodynamic benefits of L-type or wheel-shaped fins, Zhongyue provides a high-performance solution that boosts heat transfer efficiency, reduces energy loss, and extends equipment lifespan. This innovation makes H & L Fin Tubes the preferred choice for industries seeking energy-saving, durable, and low-maintenance heat transfer equipment.