Pulsar Process Measurement, Malvern, UK, has supplied a non-contacting ultrasonic measurement system to the Barry, South Wales, plant of Cabot Carbon to provide accurate monitoring of levels of fumed silica in an 11m high silo. This product has a bulk density of around 30g/l. It is used as a thickening agent in everything from gel batteries to non-drip paint, as a light-scattering agent in cosmetics and a toothpaste abrasive. However, a material as light as this presents significant difficulties in bulk measurement.  Cabot Carbon had tried a number of approaches to measure the contents, including radar, but all had failed because of the lightness and absorbency of the product. 

 

Pulsar’s approach was to supply its highest power transducer, the dB50, along with an Ultra 5 ultrasonic control unit. The dB50 is designed to measure up to 50m, so was putting a great deal of ultrasound energy into the measurement. Even so, the signal that returns to the transducer from the extremely absorbent silica is very small. Pulsar’s latest generation DATEM echo processing software identifies and dynamically tracks the material level, maintaining a link to the true material level even as it changes. www.pulsar-pm.com 

 

 

Light and powdery fumed silica with (inset) Pulsar’s 50m dB50 transducer and Ultra 5 controller