HEAT EXCHANGER

摘要

A condensing heat exchanger of the kind having a primary heat exchanger and a secondary heat exchanger connected downstream of and in series with the primary heat exchanger. The secondary heat exchanger is arranged to at least partially condense combustion gases discharged from the primary heat exchanger. The primary heat exchanger comprising a drum having a longitudinal axis and the secondary heat exchanger comprising a plurality of small diameter tubes arranged by the side of the drum and extending parallel with the longitudinal axis of the drum.