| 摘要 |
A device for detecting the presence or absence of liquid in a translucent vessel or tube which consists of a light source (11) and a light sensor (12) adjustably mounted on a platform (16) on which a tube (10) through which a fluid substance is to pass, is located. If the tube (10) contains no liquid then the sensor (12) receives the light beam and produces a signal for indication. However, if the tube (10) is filled with a translucent or opaque liquid, the light beam is deflected by refraction or scattered to prevent it from activating the sensor (12). |
