| 摘要 |
PURPOSE:To execute observation with excellent responsiveness, by measuring an optical pulse signal which is emitted from plural phototransparent parts provided on the rotary body which rotates in accordance with movement of a fluid. CONSTITUTION:For instance, a counting disk 3 made of aluminum is provided on the other end of a rotary shaft of the sensitive part 1 for detecting a movement of air or an air lump. Plural small holes 5 are made on this disk 3, and on the center axis of these small holes 5, a light emission part 6 and a photodetecting part 7 are placed through the disk 3 to be put between them, so as to be opposed. And, an optical pulse signal which is emitted from the photodetecting part 7 is counted by the counter 8, and a time for counting a prescribed number of optical pulse signals is measured. A moving speed of air or an air lump is derived by this measured time. According to such a constitution, since the whole system can be lightened easily, the inertia is made small easily, and an excellent response characteristic is obtained. Moreover, even in case when a moving speed is very slow, observation is made without containing an error. |
