Berthold Technologies GmbH & Co. KG Bad Wildbad, Germany:

D. Mörmann, Dr., Head of Technologic Department, dirk.moermann@berthold.com

J. Schmid, Eng., Engineer for software and hardware

Ergolines Lab s.r.l., Trieste, Italy:

S. Spagnul, Head of Researcher

In recent years the dominant radiometric mould level measurement has been supplemented by electromagnetic or eddy current methods. These typically provide faster response to level changes with a higher level resolution while not being influenced by mould powder addition. Yet, eddy current instruments available on the market are limited by temperature drifts, incompatibility with electromagnetic brakes, stirrers and mould coatings. We present recent technological progress and a comparison of both the radiometric and eddy current mould level measurement methods. It has to be noted that both the radiometric and the eddy current methods have their specific strengths and weaknesses. The radiometric systemis an extremely mature, stable and reliable measurement method, hardly — if not at all — influencedby temperature, electromagnetic stirrers or breaks. Due to its high adaptability it has found application for all casting formats and shapes. On the other hand, it has a rather noisy signal due to the statistical nature of radioactive decay and the measurement is influenced by slag and mould powder on top of the steel bath. While the firstissue has been addressed to some degree by introducing advanced signal filtering and optimizing the activity distribution along the rod source, the second remains a real limitation of the method.

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3. König, T.; Steinböck, A.; Kugi, A.; Mörmann, D.: Continuous mould level measurement based on adaptive filtering, Proc. 7th European Continuous Casting Conference (ECCC) 2011, 27 June — 1 July 2011, Düsseldorf.

4. www.berthold.com/process-control