Water heating boiler has a spirally wound heat exchanger with corrugated section walls through which the burner waste gases are fed to preheat the water

摘要

The burner (B) is surrounded by a horizontal spiral double walled heat exchanger (3) through which water is passed and the wall surfaces are lengthened by being wave shaped to improve heat transfer. Condensate is collected at the base and the flue gases (G) exit (70) after passing over the heat exchanger.