Electromagnetic measurement of quantities in connection with electrically conducting liquid material

An arrangement for electro-magnetic measurement at high temperature of at least one parameter of a liquid electrically conducting material contained in a container, comprising:

• an AC power supply for supplying a transmitter signal,
• at least one transmitter coil arranged to be supplied with a transmitter signal from the AC power supply for producing an alternating magnetic field,
• at least one receiver coil arranged to sense the alternating magnetic field and to generate a receiver signal in dependence thereon,
• said coils being arranged in association with a wall of said container so that the alternating magnetic field sensed by a receiver coil varies in accordance with said parameter, means connected to said at least one receiver coil for detecting said receiver signal to produce a measurement signal,
• wherein said coils are coreless transmitter and receiver coils which are essentially freely positionable and have at most a relatively few number of turns,
• at least two signal channels, each of said signal channels being arranged to transfer one of said transmitter and receiver signals, and at least one of said signal channels including signal processing means for adjustment of at least one parameter of the signal transferred by the signal channel to balance the transferred signal and remove disturbing signals,
• and means for producing counteraction between the signals transferred by the signal channels so that when the liquid electrically conducting material is in a basic position and when said signal processing means are properly adjusted the basic measurement signal obtained is at least substantially balanced with regard to disturbing and unbalance signals.