Liquid Layers: Measuring Overall Level and Interface Points
By Denny Nelson, Emerson Automation Solutions |
Accurate interface level measurement is crucial to optimizing separation processes. Today’s guided wave radar technologies make it possible to measure thin liquid layers with greater accuracy than ever
A bottle of salad dressing can illustrate a challenging level measurement application. Like the situation with oil and vinegar separation, engineers may be called to determine the individual volumes of multiple immiscible products in a single vessel. Measuring the interface level in tanks or vessels is a common and vital objective across many process industry applications where immiscible products, like salad dressing, form distinct layers. Examples include oil over water, or low-dielectric organic solvents over acid.
Some liquids do not mix due to different molecular polarity or differences in specific gravity. When stored together, they separate into defined layers due to gravity. Accurately measuring the interface level between such products can be challenging, and if inaccurate, can lead to cross contamination, which can prove extremely costly. Newer technologies provide solutions.
Guided wave radar (GWR) is effective and widely applied for interface level measurement (Figure 1), but it requires…