Using induction heating for brazing the pipe bends to heat exchanger standpipes is ideal because it offers a great deal of flexibility. In the example shown, the pipe elbows are being brazed to a copper heat exchanger’s standpipes. The individual pipe elbows are assembled with preformed solder rings into the standpipes, and are soldered within approximately 6 seconds. For this procedure the coaxial transformer with inductor is fixed to a robot arm, which stops at each pipe elbow of the heat exchanger.

Unit description:
HF-Generator
Eldec Type HFG 10 igbt

Brazing of pipe bends of heat exchangers can effectively accomplished using HF generators such as the Eldec HFG 10 igbt. In order to prevent the pipe bend from melting through (which can easily be caused by different contact feeds to the standpipe, forward heat, different melting of the solder rings, etc.), a pyrometric control of the generator output is used. Thus the generator goes up to the set nominal output with high power, and remains there for a preset time until the solder is flowing and binding completely. Due to its small dimensions, the generator can directly be attached to the robot, so that no additional space is required.