Method, device and use for the device for quantitatively determining the concentration or particle size of a component of a heterogeneous material mixture

A method for quantitative determination of a number and size of particulate components contained in a flowing molten metal medium in a container including a wall, wherein ultrasonic waves are coupled into the molten metal flowing medium, are reflected at least partially by the particulate components and reflected ultrasonic waves are detected as ultrasonic time signals which are used for the quantitative determination, comprising steps of:

• acoustically coupling the ultrasonic waves into the molten metal flowing medium with an ultrasonic transducer including a waveguide having at least a part of the waveguide immersed in the molten metal flowing medium with at least one portion of the acoustically coupled ultrasonic waves being reflected by the wall of the container containing the molten metal flowing medium or a reflector within the container to provide echo-ultrasonic time signals which are assignable to a wall region or the reflector and are used to provide a calibration reference, the ultrasonic waves being coupled into the molten metal flowing medium flowing through the container in a main direction of propagation at an angle relative to a direction of flow of the molten metal flowing medium, the ultrasonic waves flowing in the molten metal flowing medium being focused at a focal point located along the main direction of propagation of the molten metal flowing medium which is located either before or after the reflector or the wall of the container with the ultrasonic waves propagating along the main direction of propagation impinging orthogonally or at an angle on the container and are reflected;
• detecting the reflected ultrasonic waves at a location of coupling of the ultrasonic waves into the molten metal flowing medium;
• determining at least one amplitude threshold value function for establishing an amplitude threshold value for the detected reflected ultrasonic time signals with the at least one amplitude threshold being based on at least the calibration reference;
• detecting amplitude values associated with individual ultrasonic time signals which are greater than the at least one amplitude threshold value for the reflected ultrasonic time signals;
• and
• processing the detected amplitude values to provide a number and size of the particulate components.