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Mould level measurement - Measuring the steel level

Mould level measurement - Measuring the steel level
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Mould level measurement - Measuring the steel level - 1

Measuring the steel level in continuous casting MOULD LEVEL MEASUREMENT

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Introduction Radiometric based mould level measurement is the dominating technology for measuring the steel level in continuous casting. This technology has been available for more than 50 years and now with more than six thousand systems deployed. In this article performance, statistical variation, influencing factors and source selection are discussed. Furthermore, the recently developed possibility of continuously measuring the thickness of the casting powder layer is discussed. Process description Continuous casting plants enable the improvement of the steel qualities produced and...

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Radiometric mould level measurement radioactive source ■ scintillation counter (Detector) A ■ An evaluation unit The source emits gamma radiation that hits the detector that transforms the gamma radiation first to light and then to electrical pulses. The detector outputs the pulses to the evaluation unit that in turn converts the information into a mould level value, using the recorded, stored, and active calibration curve. The standard calibration curve for a radiometric mould level system is usually a calibration curve retrieved reading the 0 % (empty mould) and the 100 % (mould filled...

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Time constant and system response time influencing the size of the fluctuation is possible only through change in the impulse rate or in the time constant. An increase of the impulse rate with the given geometry can be achieved by increasing the source activity or the detector sensitivity. The limits of the source activity are given from the maximum allowed dose rates outside the mould cover and the amount of room available and the therefore, possible size of the lead or tungsten shield. An increase in the time constant is only possible on a limited basis for control technical reasons....

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This conveys that both an extended time constant (τ) and increased source activity or impulse rate (N) improve the precision of the measurement. Including the total measuring range (Lt), the casting set point (Lsp), and using the empty mould count rate (Nempty), yields the following formula for the system standard deviation at casting set point in millimeters. Applying this expression, for quite some normal conditions, for a small cross section caster Nempty = 10 000 counts per second τ = 0.8 s Lsp = 112.5 mm (75 % of the total measuring range, Lt) Lt = 150 mm conveys the statistical...

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Radioactive source Activity optimized source In former times a linear system response curve was almost a prerequisite for a well working measurement system. With modern electronics almost any shape of a monotonous response curve can easily be handled. This fact has enabled a source design called Activity Optimized Source (AOS) which allow for one of the following two features: precision at unchanged source activity source activity at unchanged precision Improved precision at unchanged source activity: This is achieved by changing the activity distribution from the lower part of the source...

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Berthold Technologies stands for excellent know-how, high quality and reliability. The customer is always the focus of our solution. We know our business! Using our varied product portfolio, our enormous specialized knowledge and extensive experience, we develop suitable solutions together with our customers for new, individual measurement tasks in a wide variety of industries and applications. Berthold Technologies is specialised in radiometric process measurements for 70 years. This is our core competence with state-of-the-art and cutting edge products and solutions covering a vast range...

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