Water heater with heat exchanger and non-circular coiled exchanger tube with decreasing grasp between coils

摘要

The heat exchanger has a combustion chamber (9) containing a coiled tubing heat exchanger (2) around a burner (5). The tube (3) has a non-circular esp. pear-shaped cross section. The gaps (11) between the individual coils of the tubing decrease in width from the side facing the burner to a minimum, in a radial outward direction.