The Integral Finned Tube has been applied successfully to a wide range of heat transfer applications to assure the highest efficiency with long life and reliable service. The continuous helical fins are radially extruded from thick-walled base tubes in a cold rotary process. The result is an extended surface that has no fin attachment, no dissimilar metal joints and no possibility of fins becoming loose or losing heat transfer capability. As well, the liner is protected against oxidation and galvanic corrosion in the presence of water, air and air borne impurities at the fin-to-tube interface.
The liner material that may be utilized are copper, copper alloys, steel, stainless steel, titanium or any variety of special metals to handle specific aggressive environments. The finned portion is as corrosion resistant as the alloy from which it is produced. Bimetal type hifin tube is classified as an «interference fit» finned tube. There is more than an ordinary mechanical engagement between the liner tube wall and the fin tube base. There is, in fact, an elastic deformation of both metals to maintain intermetallic heat transfer contact by virtue of the contact pressure. Thermofin finned tube is further unique in that it provides a continuous sheath or «muff» at fin material over the liner tube.
As fabricated, our finned tube has an extremely high contact pressure at the interface liner tube and outer finned tube. It is this pressure that permits the Bimetal Tube to operate safely at elevated temperature without loss of heat transfer capability. Where extreme temperatures are encountered, heat transfer design safeguards are used to ensure design conditions are continuous met.
The superior qualities of our finned tubes are readily apparent from operating experience. The results of in-service evaluation comparing Integral Bimetal Hifin to other type of extended surface confirm that only the integral finned tube could retain heat transfer capability very near the original design requirement. The embedded type and the helically wrapped type suffered serious corrosion conditions between fins and liner tube and as result were unable to maintain thermal capability.
The mechanical process of manufacturing an integral finned tube make that the fins are more rigid and can withstand high impact without losing their form. This ensures good efficiency that is expected when using an extended surface for heat transfer.