| 摘要 |
PURPOSE:To reduce a wind velocity distribution in an air duct measuring part due to outflow and inflow of heat through a drum of an air duct, by providing a bush which is connected to an upper-steram end of the measuring part, and is expanded and opened into the contracted flow part. CONSTITUTION:In case when a temperature difference has been generated in the upper part and the lower part by the influence of sunlight or an ambient temperature, etc., a temperature difference is generated in the inside wind flow, too. In case when the temperature of the upper layer part of the wind is high, and that of the lower layer part is low, the upper part of the inside of the drum is accelerated. In the upper layer part of an air duct, that is to say, in the inlet part of a contracted flow part 5, a high- temperature and accelerated wind flow which has come between the contracted flow part 5 and a bush 11 flows to an opening part 12 opened to the contracted flow part 5 whose resistance is small, instead of flowing toward a measuring part 7, is exhausted to the outside of the drum. In case of the lower layer part, since the opening part 12 has been provided, the wind flows easily, therefore, the upward flow flows in the corrected direction, and also an eddy flow is annihilated. On the contrary, in case when the temperature of the lower part is higher than that of the upper part, the opposite phenomonon occurs. |
