Liq. level detector for capillary tube - uses internal wall as cylindrical mirror illuminated by laser beam whose reflection is detected for determination of level of liquid

摘要

The process is used to detect the presence of a liquid (18) at a certain level (20) in a transparent tube (10), such as a capillary tube. The inner surface of the tube (10) is used as a cylindrical mirror. The tube (10) is lit, at the level (20) at which the liquid (18) is to be detected, by a narrow light beam (12) such as a laser beam. The reflected light (14) is detected by a light detector (16). When the liquid (18) reaches the level (20) lit by the light beam (12) the tube (10) stops reflecting light to the detector (16). The process can be adapted to detect liquids at several levels in several tubes. The tube is capillary of the capillary type.