Interface level detection - what to consider

摘要

Compared to a standard level measurement in liquids, the detection and measurement of interfaces have their own particular challenges, leaving many applications without reliable level measurements. Most popular today are the electronic or non-mechanical solutions with no moving parts which offer higher long term stability, and little or no maintenance. Ideally, an interface would be a clear separation between two media with different densities. In practice however, a transition or emulsion layer often exists between the two media. This creates multiple interfaces if one considers the transition from the first medium to the emulsion layer, and then from the emulsion layer to the second medium. The addition of each new medium creates two new interfaces. For example, in oil/water separation during crude oil extraction, there is a sedimentation layer at the bottom, consisting of sand and other heavy substances, followed by a liquid/solid interface to the water layer.