PURPOSE: To permit to supply hot air to a blast furnace continuously by a method wherein high-temperature gas is flowed through primary path, defined by a partitioning plate, heat is transferred to the heat accumulating disc of refractory bricks, exposed to the inside of the path, and the heat accumulating disc is rotated to expose it to secondary path.

CONSTITUTION: When the high-temperature gas is flowed into a direction, shown by an arrow sign (a) in the diagram, through the primary path 17, the high-temperature gas flows under contacting with the heat accumulating disc 8 and transfers the heat thereof to the heat accumulating disc 8. When high-temperature pressurized air is flowed through the secondary path 18 into the direction of an arrow sign (b), the air moves from the primary path 17 to the secondary path 18 contacts with the exposed heat accumulating disc 8 and is heated, thereafter, the air flows out of the secondary path. According to this operation, the heat exchanger may transfer the heat of the high-temperature gas to the air to be heated continuously by the rotation of the heat accumulating disc 8.