Author: L. A. Kivioja
Co-Author: J. Merrick Penicka, Horst Friedsam
A New Hydrostatic Leveling System
This new Hydrostatic Leveling System uses a free upper surface of a liquid (distilled water) as an optical reflector. A thin pencil of light is sent into the liquid container through an optical window. After a total reflection from the upper free liquid surface, the light hits a spot on a linear or a two-dimensional Optical Position Sensor at the bottom of the liquid container. When the liquid level changes, the reflected light moves to another spot on the sensor. Changes in liquid levels can be measured with better than one micron (0.001 mm) accuracy. Prototypes were built and tested. The humidity of the gas above the liquid surface is never a problem. The gas pressure above the liquid is shared in all liquid containers by inter-connected gas tubes. It can be a closed system without vents. All containers are also inter-connected by liquid tubes in the traditional manner, and the same equipotential surface of the free upper liquid surface is present in all liquid containers.