Firetube economizer

摘要

A firetube is mounted in a body of liquid to transmit heat to the liquid. A burner of fluid fuel is attached to one end of the firetube to discharge products of combustion into the firetube. The cooled products are discharged from the other end. The last portion of the firetube in the liquid bath has a series of tubes mounted through its walls. Liquid of the bath passes through the tubes and is heated by the products of combustion in contact with the tubes from within the firetube.