| 摘要 |
PURPOSE:To maintain virtually constantly a total flow rate of air flowing through a flow passage by changing freely a cross sectional opening area of a branch flow passage and hence varying the flow rate of air based on the application of a damper which changes the flow rate of air flowing into each branch flow passage. CONSTITUTION:The shape of branch flow passages 25 and 26, the size of a humidifier 11, flow passage resistance and the like are determined so that the resistance against the air current flowing through the two flow passages 25 and 26 may be virtually identical with each other. At the same time, an orifice 28 is installed to an opening section 22 on the end of the branch flow passage 26 on the downstream side. Therefore, when an attempt is made to reduce the opening cross sectional area of the branch flow passage 25 which introduces air 18 to a humidifier 11 by sliding a damper 27 for example, the flow rate of air to be supplied to the humidifier 11 will be reduced, which results in a reduction in the quantity of humidification. At the same time, the opening cross sectional area of the branch 26 which introduces the air 18 to an opening section 22 will be increased, which increases the quantity of air flowing through the opening section 22. As a result, the flow rate of the air 18 flowing through a flow passage 24 in a duct member 21 remains almost unchanged. |
