Patent ID: 7086153

Claim:
A method of manufacturing a plurality of heat exchanger tubes each having a predetermined length, the method comprising: providing a strip material having a specified width; forming a plurality of cutting grooves in the strip material, each cutting groove extending entirely across the specified width and being spaced by the predetermined length, each cutting groove including at least two thin parts separated by a thick part; rolling the strip material into a tubular shape to form a continuous tube; separating the continuous tube at each cutting groove by applying external force to parts of the continuous tube; wherein applying the external force to parts of said continuous tube comprises passing said continuous tube between at least four rollers arranged into two groups so as to have one group of rollers offset in a movement direction of the strip material from one other group of rollers, and set to a distance between the two groups of rollers slightly smaller than a short diameter of said continuous tube so as to make said continuous tube undulate between said two groups of rollers.