Level Measurements Under Water? Balluff Has the Answer

Dec. 22, 2008
Balluff Introduces SMARTLevel Capacitive Sensors

The first thing you learn when measuring heavily foaming or dipolar liquids with a standard capacitive sensor is that setup procedures for such applications are difficult, time-consuming, error-prone and, sometimes, flat-out impossible.  Then you learn that these sensors are unreliable on foamy liquids or those that create film or material buildup on the walls of their containers. You have to readjust the sensors constantly. In order to get reliable and dependable sensing results, you have to use a trim potentiometer to adjust the signal sensitivity according to the application requirements.

These frequent readjustments offer only short-term results, and the overall operational reliability of these conventional capacitive sensors is unsatisfactory.

Now Balluff has come to the rescue with its new, patented SMARTLevel capacitive sensors that the company says eliminate all the problems associated with standard capacity level sensor technology.  SMARTLevel sensors accurately sense correct levels of aqueous or highly conductive liquids through glass or plastic walls up to 12 mm thick.  The SmartLevel technology allows these sensors to distinguish automatically between non-metallic tank walls, possible interferences from foaming of material build-ups and the true level in the tank.

Bjoern Schaefer, product manager at Balluff, explains how the SMARTLevel sensors work: “Let’s say we’re making cookies. We have a cookie slurry with chocolate chips in it that leaves a residue on the sides of the tank. The SMARTLevel sensor automatically sees only the true level, not the residue.”

SMARTLevel sensors work with a special high-frequency oscillator whose amplitude is correlated with two independently acting sensing electrodes that continuously try to force themselves into a balanced state. That’s why, unlike standard capacitive sensors, the sensor independently measures the capacitance of the container wall without ground reference and the capacitance of the conductivity of the liquid with ground reference.

SMARTLevel sensors also readjust themselves when confronted with changing container compositions during checking procedures or changes in liquids during different production runs. They never require any maintenance cleaning procedures. This means that for the first time, a capacitive sensor can operate accurately for an indefinite amount of time, regardless of debris buildup and/or in the presence of heavy foam, without any downtime or production lost.  

SmartLevel sensors are suitable for all water-based liquids and other highly conductive liquid compositions, such as acids, detergents and organic wastes. Common applications include filling situations, storage and mixing stations, and general process monitoring in chemical, medical and water/wastewater environments.

SMARTLevel sensors offer an unprecedented simplicity during the setup routine, since they do not require any individual adjustments to the specific container wall. They also do not falsely recognize material build-up, foaming or filming in the application, providing an extraordinary level of reliability and safety.

SMARTLevel sensors provide cost-effective, reliable and easy-to-use point-level monitoring for a wide array of industries and applications. Balluff offers this technology exclusively in a wide array of sensor configurations to accommodate a full range of applications and environments. Standard sensor housing materials include PVC, PBT, POM and stainless steel. Advanced housing materials, such as complete PTFE and polypropylene, are available.

SMARTLevel sensors are “an extremely significant breakthrough product because of the value they bring to companies,” says Schaefer. “You don’t have to clean the tank, stop production and remove all the film, etc., in order to make the sensor work. This saves much more than the total cost of the sensor. They give a huge productivity boost.” 

For more information, contact Bjoern Schaefer at 800.543.8390, x 3317 or go to