Types of Level Instruments in Process Control

Tuning fork level controls
(form of echo level sensing)

In many industrial processes, the measurement of level is critical. Depending on the nature of the material being measured, this can be a simple or complex task. Several different technologies for sensing level are briefly explained here.




Sight Glasses or Sight Gauges
A very simple type of level measurement device for direct visual measurement of level in a tank or vessel. A sight gauge is usually a clear glass or plastic tube connected to the a vessel at the top and bottom of the level range needing to be viewed. As long as interface (different fluids with different densities floating on each other) the fluid level inside the vessel will be at the same hight as the level in the tube.