LIQUID LEVEL DETERMINATION METHOD AND APPARATUS

摘要

The method and apparatus involves directing a beam of radiation from a first emitter (9a) at a vessel (7) containing a liquid, and detecting by means of a first detector (9b) whether the beam is deflected by the upper surface of the liquid. This gives information concerning the level of the liquid. A second emitter (10a) and a second detector (10b), at a higher location than the first emitter (9a) and detector (9b), may be used to give additional information.