BM 100A: Measuring carbon black level in a silo

BM100A blows up a storm in carbon black process
KROHNE's BM 100A has performed well where rival products have failed on a notoriously difficult application measuring carbon black.

The customer is a manufacturer of carbon black, a burnt oil residue with a very fine talc-like consistency used as a colourant. In the application, the carbon black powder is cycloned into a silo which is a vertical cylinder with a conical bottom. The hot powder is blown in from the top and settles to the bottom from where it discharges to process. In the middle of the silo, a drive shaft with agitator blades ensures that the powder continues to flow freely through the silo.
The application is particularly problematic for measuring instruments. Only the settled product needs to be measured, but most measuring instruments are confused by the cloud of carbon powder and unable to differentiate it from the settled dust to reliably determine the level of product.
Following unsuccessful attempts to use a competitor's non-contact method, KROHNE's BM 100A meter was installed through the roof of the silo, descending some 3 metres into the vessel to just above the agitator blades. The BM 100A is able to differentiate between the air-borne powder and the settled powder due to the greater dielectric strength of the settled product compared to the dust cloud. The BM 100A can measure down to lower dielectric strengths than competitive units.

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