Abstract: The invention is concerned with a system for monitoring the feed rate of a cut strip which is to be applied to a rotating tube for use in the production of fin tubing and includes a dancing roll to monitor the feed rate of the strip in response to the tension applied by the strip to the dancing roll as it is fed from a direct hydraulic drive during application to the rotating tube, the tension in the strip being maintained essentially constant throughout.

Abstract: A series of thin-walled, heat exchange tubes are soldered to return bends of similar materials so as to complete a flow path through the tube bundle by a process which comprises press-fitting the return bends to the tubes, preheating the return bends and portions of the tube adjacent the bends to a temperature, the average of which is approximately the soldering temperature, soaking the preheated portion in a liquid which will equalize the temperature of the various preheated portions, and ultrasonically soldering the return bends to the tubes.