| 摘要 |
PURPOSE:To cause cooling air to pass through cells of a drum of a heat exchanger to rob the drum of heat thereby to prevent after heating after the fire extinguishment of a burner by forming the drum of the heat exchanger into a honeycomb structure using ceramics, and directing the cells of the honeycomb structure toward the direction of a combustion gas flow. CONSTITUTION:Heat is supplied from a flame or a high-temperature combustion gas to the inner surface 20 of a drum 3, and is transmitted to a corrugated sheet 13. Upon this occasion, cooling air 17 robs a planar sheet 14 and the corrugated sheet 13 of heat. However, since the corrugated sheet has a large surface area, the quantity of heat taken away by the cooling air passing through cells 16 is large. Further, since the cell walls around the peripheries of cells 16 are constituted by a heat insulating material such as ceramics, the bouyancy of cooling air is sufficiently utilized and the cooling effect is large cut the temperature rise of the outer surface of the drum is small. For this reason, it is possible to shorten the distance between the heat exchanger and an outer shell and to ministurize the water heater.
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