PURPOSE: To improve of a rate of thermal recovery by a simple means by a method wherein a plurality of metal plates are arranged so as to be extended along a flow of fluid flowing outside of a plurality of metal pipes of manifold type recuperator with being adjacent thereto.
CONSTITUTION: When the manifold type recuperator is installed in a chimney 1 of a heating furnace to pre-heat a combustion air, two sets of a plurality of metal pipes 2 crossing with the chimney 1 are arranged vertically, both the air suction duct 3 and the discharge duct 4 are provided at each of the upper ends of the metal pipes. The lower end is connected by the connection duct 5, the combustion air flowing from the suction duct 3 into the pipe 2 is fed to the discharge duct 4. The metal plate 6 is arranged adjacent to each of the metal pipes 2, their both ends are fixed to each of the ducts 3W5. The metal plates 6 are positioned between the pipes 2 equally spaced apart at frontward, backward, leftward and backward directions with respect to a flow of the discharged gas in the chimney 1 and further arranged to show its width being in parallel with a flow of the discharged gas.