Patent ID: 7422429

Claim:
A heat exchange furnace comprising: a combustion furnace module adapted to burn fuel such that combustion gases are generated therein; a passageway module including an annular surrounding plate disposed around said combustion furnace module so as to define an annular heat exchange space therebetween, a top annular plate connected removably to said combustion furnace module and having an outer peripheral portion connected fixedly to an upper end of said surrounding plate for sealing an upper end of said heat exchange space, a bottom annular plate connected removably to said combustion furnace module and having an outer peripheral portion connected fixedly to a lower end of said surrounding plate for sealing a lower end of said heat exchange space, and at least one conduit unit including a plurality of conduit sets that are disposed within said heat exchange space and around said combustion furnace module and that have upper ends extending sealingly through said top annular plate, and lower ends extending sealingly through said bottom annular plate; and a gas-guiding unit including an upper guiding module disposed removably on and above said top annular plate and formed with a gas outlet unit for permitting the exhaust of the combustion gases from said heat exchange furnace therethrough, and a lower guiding module disposed removably on and under said bottom annular plate and cooperating with said upper guiding module so as to limit a direction of flow of the combustion gases through each of said conduit sets such that said conduit sets as well as said upper and lower guiding modules constitute cooperatively a serpentine gas flow path for the combustion gases, said gas-guiding unit guiding the combustion gases to flow from said combustion furnace module to said gas outlet unit via said serpentine gas flow path.