| 摘要 |
PURPOSE:To reduce the blast noise of a fan and to enhance heat exchanging efficiency by uniformizing the velocity distribution of air passing through the respective parts cf a heat exchanger in the circumferential direction thereof by changing the distance between the leading end surface of a bell mouth and the lower end of the fan along the circumferential direction of the fan. CONSTITUTION:A shroud 9 constituted so that the distance DELTAa between the upper end part 16 of the shroud 9 and the leading end part 14 of a bell mouth becomes large gradually on the 1/2 outer circumference of a circle of a fan inserting opening part and becomes small gradually on the other 1/2 outer circumference of a circle thereof is provided to the upper surface of a unit. Since the distance DELTA between the leading end part 14 of the mouth and the lower end surface 13 of a fan 7 changes in the circumferential direction of the fan, the area of a heat exchanger element 2x changes in inverse proportion according to the distance DELTA to act so as to uniformize the velocity distribution of air in the circumferential direction of the respective parts of a heat exchanger 2. As a result, since heat exchange efficiency is increased and the max. value of air velocity becomes low, the air passing resistance of the heat exchanger is reduced and blast noise is reduced with the reduction in the load of the fan. |
