| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to generate a high temperature, strong circulating flow and ensure a large amount of high temperature circulation with a low power. SOLUTION: A heat source burner 3 for effecting combustion with forming flame within a furnace 2 and an outside-of-furnace circulation line 4 for extracting combustion gas of the furnace 2 out of the furnace 2 and recirculating the gas into the furnace 2 through another portion are provided. The outside-of-furnace circulation line 4 has thermal storage bodies 5A, 5B provided in in-furnace gas outlet and inlet portions 9A, 9B located in a vicinity of a furnace 1 and a circulating fan 6. A flow passage switching device 7 is provided for changing gas flow direction relatively with regard to the thermal storage bodies 5A, 5B by selectively connecting a suction side and a discharge side of the circulating fan 6 to either one of the thermal storage bodies 5A, 5B, and a heat extracting means 8 is provided for extracting or diluting heat to change gaseous properties of the gas flow in the outside-of-furnace circulation line 4 between the two thermal storage bodies 5A, 5B. By alternately firing the heat source burner 3, a high temperature strong circulating flow 10, in which flow direction of the gas flow is periodically reversed in tune with firing of the heat source burners 3, is formed within the furnace 2. |
