Application advice: Pressure sensors for water treatment

Life in water treatment applications is tough on sensors. Baumer offers pressure and level sensor designs that can take it.

Peter Welander

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While working with water may sound easy, water treatment applications can place high demands on pressure and level measuring instruments. Wastewater is difficult with aggressive elements and suspended solids. Desalination of seawater is highly corrosive. For these applications, Baumer offers sensors designed for high-vibration environments and aggressive media. For example, sensors made of Hastelloy C or Monel with a ceramic sensing element are available for desalination plants. Flush mount versions are offered for sewage applications.

Baumer says that pressure and level measuring devices for water treatment applications have to be extremely robust. This extends beyond material selections for corrosion resistance into other aspects of those environments. For example, devices have to be highly resistant against continuous vibrations generated by volumetric pumps. That vibration resistance has to be tested according to the EN 60068-2-6 standard for verification. There are additional challenges caused by high pressures involved with reverse osmosis processes, along with the formation of foam, suspended solids, and condensation in tanks.

Baumer offers units with a wide range of process connections and galvanically isolated output signals. They are resistant against shocks and vibration, and feature high temperature resistance, accuracy, and long-term stability. The company suggests specific products for water treatment plants:

• Submersible probe ED752 for hydrostatic depth measurement;
• Modular PB series pressure transmitters;
• TED digital pressure switch;
• FlexLevel switch; and
• Ultrasonic sensors UNAR and UFAR.
These applications are growing in importance as the number of desalination plants grows and more sophisticated wastewater treatment processes such as ultra-filtration gain wider deployment.

-Edited by Peter Welander, process industries editor, PWelander@cfemedia.com
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