Proven Technology and Still State of the Art: The Ultrasound Cleaning System

Ten years ago, in 2002, WTW (Germany) introduced an advanced ultrasound cleaning system for its optical on-line sensors VisoTurb (turbidity) and ViSolid (TSS).

The permanently emitted ultrasound signal focused to the measuring windows, in combination with smooth and hard sapphire glass windows efficiently prevents the development of all kinds of fouling regardless of the application. The ultrasound vibration also prevents any accumulation of air bubbles in the area of the measuring window that might cause measuring errors.

This highly efficient cleaning technology reduces the need for manual cleaning and maintenance to an absolute minimum. No tear or wear parts nor any replacement service, e.g. of sealings, are needed, unlike with mechanical wiper systems. There is no sensor downtime, hence saving operation costs.

The photos show WTW optical sensors used at BASF’s Ludwigshafen wastewater plant. The VisoTurb worked four and the ViSolid for six weeks before they needed a manual cleaning.

Now WTW’s unique ultrasound cleaning technology has been integrated in the new spectral sensors family CarboVis, NitraVis and NiCaVis. These sensors can measure parameters such as nitrate, COD, BOD, TOC and TS directly in the wastewater process.

WTW’s ultrasound technology is well proven and still the state of the art in effective cleaning of process sensors.