Central heating boiler unit - has heat exchanger built up of figure-of-eight shaped tubes in adjacent configuration

摘要

The boiler comprises a heat exchanger built up of a number of figure-eight-shaped tubes (2,3) one behind the other. A burner is mounted in the chamber enclosed by the bottom parts of the tubes, while near their tops is an outlet for the combustion gases. On the outside of the tubes there can be strips joining together so as to form a casing, open only at the bottom. These strips (20) can be on the inside of the vertical runs of the tubes.