| 摘要 |
PURPOSE:To always measure the boundary level of liquid-like spongy sediments by separating light into reflected light and transmitted light through a half mirror and measuring first and second transmitted light quantities, and then, finding the boundary level from the ratio between both light quantities. CONSTITUTION:Laser light La from a laser oscillator 41 is separated into transmitted light (reference light Lb) and reflected light La through a half mirror 42 and the reflected light La is made incident on a cylindrical long object 52 through an exit window 49a and entrance window 49b after the light La is reflected by a reflecting mirror 48a. The laser light attenuated through the object 52 is made incident on a photodetector 46 after the light is reflected by a reflecting mirror 48b. On the other hand, the reference light Lb is made incident on another photodetector 44 after the light La is attenuated through an attenuation filter 43 and the signal of the photoreceptor 44 is outputted as an output signal Oa through an amplifier 45. The signal of the photodetector 46 is outputted as an output signal Ob through another amplifier 47. The gains of the amplifiers 45 and 47 are adjusted in advance so that the signals Oa and Ob can become Ob/Oa=1. An arithmetic section calculates the Ob/Oa and a comparator section finds the boundary level of sediments by comparing the Ob/Oa with a target value previously stored in a setting section. |
