Bleed out detector for direct chill casting

Casting apparatus for direct chill casting of molten metal comprising:

• a mold having an inlet to receive molten metal, a side wall and an outlet for withdrawal of a casting from the mold;
• metal delivery means for delivery of molten metal into the inlet of the mold;
• cooling water spray means positioned to direct cooling water sprays which impinge directly onto an outer surface of the casting emerging from the outlet, thereby to cool said surface;
• and
• an infra-red detector positioned adjacent a region in which said water sprays are directed onto the outer surface of the casting being withdrawn from the outlet of the mold, the detector being exposed to radiation from said region as the casting is cooled by the water sprays, so as to essentially detect cooling water temperature,
• whereby any molten metal bleeding out from the casting in said region immediately exposes the infra-red detector to high temperature radiation, so as to produce a response dependent on a difference between cooling water temperature and molten metal temperature.