| 摘要 |
PURPOSE:To compact a back flow part, and also, to realize a flow rate detecting device by which it is unnecessary to change an external form even by a use flow rate range, by providing a straightening vane in a passage, in a revolving ball type flow rate detecting device. CONSTITUTION:A sphere 3 turning in the vertical direction against a flow is provided immediately behind a fixed impeller 2 for bringing a fluid to an axial turn, and on its upper part, a rotation detecting device 7 for detecting a rotation of this sphere 3 is provided. Also, on the back flow part of this sphere 3, a straightening vane which is curved toward the flow direction, and has formed passages 8a, 8b in the center part and the peripheral part is provided. By changing an area of the passage 8b of this peripheral part, a flow rate range which can obtain a stable rotational area of the sphere 3 can be changed. That is to say, when an area of the passage 8b is made small, the upper limit of the flow rate by which the sphere 3 turns stably is limited, and on the contrary, when said area is enlarged, the upper limit of said flow rate is widened. Accordingly, a usable flow rate area rises as a whole.
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