Which principle does a bubbler level control system operate off?

A bubbler level control system operates based on the principle of differential pressure. In this system, a tube is submerged to a specific depth in a liquid, and air is forced through this tube. As the liquid level changes, the pressure at the bottom of the tube also changes, resulting in a differential pressure that can be measured. This differential pressure corresponds to the height of the liquid column above the tube's opening.

By measuring the changes in pressure caused by the varying liquid level, the bubbler system can accurately determine the level of the liquid and control the corresponding processes, such as filling or draining tanks. This method is particularly useful because it provides continuous level measurements and is not affected by changes in liquid density, making it an effective choice in various applications.