Test liq. level monitoring device - light beam from two nearly coaxial bars is passed through liq. to photoreceiver

摘要

The test liq. level is monitored and measured within a test vessel. The light beam (6) is produced by two nearly coaxial light conducting bars (2, 3) whose end faces (8, 9) are immersed in the liquid. End face (8) of the light conducting bar (2) nearer to the light source is inclined to the direction of light propagation, while the end face (9) of the other bar (3) is normal to this direction. The photoreceiver (5) can be a photodiode or cell. The light source (4) is pref. a l. e. d. and the bars (2, 3) of glass of the same optical thickness.