| 摘要 |
PURPOSE:To obtain a non-contact type flowmeter free from maintenance etc., by determining change of flow by irradiating into the liquid surface a light beam of strong directional property, such as a laser beam and change of received magnitude of the reflected beam. CONSTITUTION:When a liquid level at the max. allowable flow is assumed to be S0, a light receiving apparatus 7 is so arranged that, when the level reaches S0, a reflected laser beam L' with the beam width d0 becomes wholly incident to a light receiving unit 7'. Namely, at the liquid level of S0, the laser beam reflected at the part identified with a symbol A0 becomes wholly incident to the light receiving unit 7'. However, when the liquid level drops down to S1 and further to S2, only the reflected laser beam (beam corresponding to beam widths d1, d2 respectively) from the part identified with symbols A1 and A2 becomes incident to the light receiving unit 7'. |
