| 摘要 |
PURPOSE:To prevent the generation of an after-boiling phenomenon and noises and also of drain on the front flow side of circulating water by a method wherein a heat absorbing pipe of the fin type heat exchanger is made gradually smaller in diameter from the front flow side of the circulating water and heat absorbing fins of the heat absorbing pipe located at the side part of the front flow of a combustion gas are made gradually shorter in length. CONSTITUTION:The diameter of the heat absorbing pipe 1 is made gradually shorter as shown by d1, d2, d3 and d4 as the pipe extends from the front flow side to the rear flow side of the circulating water and lengths l1, l2, l3 and l4 of the heat absorbing fins 2 located below the heat absorbing pipe 1 are made gradually shorter. The distance of heat transfer of the combustion gas flow A under the heat absorbing fins 2 with respect to the heat absorbing pipe 1 is larger on the front flow side of the circulating water so that the temperature of the gas is kept high without dropping below the dew point of the gas to thereby prevent the generation of drain. Further, the quantity of the water stored in the heat absorbing pipe 1 at the time of suspension of a hot water supply is larger on the front flow side than on the rear flow side and the temperature of the water is considerably low so that the rise in temperature due to the maintenance of the heat exchanger is not so high and so the after-boiling phenomenon scarecely takes place. Further, as the flow velocity of the circulating water on the rear flow side of the heat absorbing pipe 1 are accelerated on the rear flow side, the overheating and boiling of the water in the heat absorbing pipe 1 are checked by the agitating action of the water, to thereby prevent the generation of noises. |
