Sensor and method for measuring the surface level of a liquid phase metal

A sensor for measuring a level of a surface of a liquid phase metal for a continuous casting plant that includes an ingot mold having an upper face into which an opening, into which the liquid metal is fed, leads, the sensor comprising:

• an air excitation coil perpendicular to the upper face of the ingot mold, powered by a current to create a magnetic field whose field lines are propagated along upper field lines which move away from the ingot mold and along lower field lines which cover the upper face of the ingot mold and the molten metal surface,
• a lower air reception coil parallel to the excitation coil in which an induced voltage is generated by action of the lower field lines, the latter being modified by a variation of the level of the molten metal surface, and
• an upper air reception coil parallel to the excitation coil, and directly superposed on the lower reception coil, and with geometry and characteristics identical thereto, in which an induced voltage is generated by the action of the upper field lines, the latter being substantially free of disturbances generated by the molten metal surface,
• wherein the sensor is designed to be positioned on the upper face of the ingot mold in proximity to the opening.