Fintube

A fintube is a heat exchanger tube fitted with fins to extend its external surface area and improve heat transfer between the tube contents and the surrounding gas. By increasing the area in contact with air, fintubes enable higher thermal efficiency in compact footprints. They are commonly used in air-cooled condensers, evaporators, and other air-to-fluid heat transfer applications.

Construction and materials: Fins are typically made of aluminum, copper, or stainless steel and are attached to the outside of the tube by mechanical crimping, brazing, or welding, or sometimes formed integrally by extrusion. Fin patterns may be straight, staggered, or helical, and fin density is specified as fins per inch (or per millimeter).

Design considerations: Key parameters include fin height, thickness, pitch, and the number of tube passes. These influence heat transfer, pressure drop, and fouling propensity. Fin coatings and protective barriers extend corrosion resistance in aggressive environments. Fintube geometry is chosen to match the fluids, temperatures, and flow rates of the application.

Applications: Fintubes are widely used in air-cooled condensers and evaporators, process air coolers, and some boiler or refrigeration equipment. They are favored in installations where compactness and high surface area are required, or where free-air cooling is available rather than liquid cooling.

Manufacturing and standards: Manufacturers produce fintubes in a range of tube diameters, fin heights, and materials, with quality control and testing to ensure bond integrity and performance. Designs follow industry practices and customer specifications, and performance is validated through thermal testing and pressure ratings.

See also: finned tube, heat exchanger.