G-Fin Tube is used for high temperature services with a maximum design temperature of 450º C. A helical groove is cut into the finned tubes, the fins are peened to push the displaced metal back into the fin to form a strong mechanical bond. The fin density is 157 fins/meter to 512 fins/meter (4 fins/inch tp 13 fins/inch) and fin height is 6.35 mm to 20.5mm (0.25 inch to 0.807 inch), any available metal tube can be finned, up to 12.2 meter long. Tube diameter – 14.29mm OD to 50.8mm OD.
L-Fin Tubes are used for moderate temperature service with a maximum design temperature of 150º C. The fin strip is formed into an ‘L’ shape and the tension wound onto the base tube. The feet of the fins cover the whole surface between the fins, affording considerable corrosion protection of base tubes for lower temperature or intermittent operation. Tubes may be of any available metal and fin density, height and length limitations are the same as G-Fin. The cost of L-base tube is about the same as G-Fin for steel tube, but is cheaper for higher cost tube as G-fin requires a gauge thicker tube to have the same wall thickness under the fin.