| 摘要 |
PURPOSE:To reduce the pressure loss of a revolving flow of hot air, to suppress the rise in the temperature of a heat exchanger and to make uniform the hot air blow-off temperature by allowing the contor of fins in the vicinity of a burner which are provided around the outer periphery of a heat exchanger to assume one which is curved to the rotational direction of a hot air flow so as to constitute a guide portion. CONSTITUTION:An exhaust gas is generated in a combustion chamber 2 of a burner 1, and a revolving flow of hot air within a blast passage 19 due to a hot air fan 6 is guided to an outer wall 16 in the vicinity of the wall of a casing 11 by a guided portion 18 made of fins 15 the contor of which is curved in the rotational direction of the hot air fan 6. Thereafter, the hot air flow passes fins 17 axially provided at a height the same as that of the fins 15. Thus the rise in the temperature of an outer wall 16 in the vicinity of the combustion chamber 2 is suppressed, and the flow component along the wall of the casing 11 is reduced, thus making uniform the temperature of hot air flow. Further, the hot air flow comes into collision with a guide portion 18, whereby a turbulence is created and the heat exchange efficiency is improved. |
