Measuring sensor, system and method and casting machine

Sensor for detection of at least one physical quantity selected between:

• temperature of at least one portion of a crystallizer of a mould of a casting machine of a liquid metal;
• position of a meniscus or level of said liquid metal within said crystallizer;
• in which the sensor is intended to be installed inside the mould, the sensor comprising a case provided with a chamber comprising a closing cover in which the cover is placed at a detection face, the cover bearing internally to the chamber at least one first series of ultrasonic elements which are placed reciprocally vertically spaced according to a development direction in length of the sensor, which is parallel with respect to a development direction in length of walls of the crystallizer, wherein the first series of ultrasonic elements comprises at least one first ultrasonic element, a second ultrasonic element, a third ultrasonic element, each ultrasonic element being alternatively configurable as transmitter of transmission ultrasonic waves and as receiver of reception ultrasonic elastic waves, which are return ultrasonic waves from the crystallizer comprising echoes of reflected waves of the transmission ultrasonic waves of the same ultrasonic element, in which the sensor includes attenuation elements, the attenuation elements being made of a material with attenuation effect on acoustic waves characterized in that wherein each ultrasonic element is placed on the cover according to an orthogonal orientation with respect to the development direction in length of the sensor for orthogonal incidence of transmission ultrasonic waves with orthogonal incidence with respect to the crystallizer, the attenuation elements being positioned sideways with respect to the cover in correspondence with each ultrasonic element for attenuation of echoes from directions other than the orthogonal direction, the attenuation elements being longitudinal elements with development in length along an orthogonal direction with respect to the development direction in length of the sensor, the attenuation elements being made of material with a surface with sawtooth ridges and recesses for the increase of the absorbing and attenuating effect.