FIELD: metallurgy, in particular, equipment for detecting inflow of molten metal from metallurgical vessel. SUBSTANCE: method involves detecting luminescent objects; forming image of zone defined between two planes by means of one light source; forming image of luminescent object; converting light flux of this image into electric signal delivered to outer circuits as functional information. Apparatus has optical light detection system having objective with adjustable focal distance, photoelectric converter, converter, comparator, buffer cascade, power unit and light source. EFFECT: increased efficiency, simplified construction and provision for precise data. 15 cl, 6 dwg
