Steel boiler with cast iron heat exchanger - has steel insert in neck of exchanger welded to inner face of steel casing

摘要

The boiler has a steel casing (2) forming a combustion chamber on one side with a water jacket (8) on the other side. A cast iron heat exchanger (7) projects into the combustion chamber and has a neck (17) fixed to an opening in the steel casing to give a communication from the exchanger into the waterjacket. An annular steel insert (33) is screwed into an annular threaded hole tapped axially into the neck of the heat exchanger. The insert projects beyond the neck and is welded (35) to the inside of the steel casing.