E-Zine February 2011
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Level measurements can be used to keep tanks in the plant within reasonable operating limits.
Tanks that become empty can potentially upset production due to the inability to feed the downstream process.
They can also cause a lack of flowing material that can damage equipment, such as pumps.
On the other hand, tanks that overflow can potentially create environmental hazards.
Level measurements may be used to manipulate the flow of material through the plant, such as in a sewage treatment plant where a high level in the primary collection tank would increase the flow through the entire treatment plant.
Level measurements may be used to determine the interface between two materials.
In some applications, the location of a liquid/liquid interface can be important to ensure that the separation occurs properly.
Most level measurement applications may seem routine but they can become relatively difficult to implement when additional factors are considered. For example, there are many level measurement systems that can be used to measure the level of a liquid in a vessel. However, the number of viable measurement systems decreases significantly when the vessel is agitated and operates at 200ºC and 40 bar. Foaming and the effects of filling and emptying the vessel can further limit the viability of many level measurement technologies. Level measurement applications are rarely “cookbook” and typically require careful engineering.
Excerpted from The Consumer Guide to Non-Contact Level Gauges