metal can be achieved in fact when for example each of the inductors 13 and 14 is energized by currents of the same level in phase the forces created in the annular zones 15 and 16 operate together to return the liquid metal via the extendable channels thus at the same time heating and transferring operations are performed conversely if each of the inductors 13 and 14 is energized by currents of the same voltage but phase shifted by 180 u00b0 the magnetic fields created are directed from one core to the other core which prevents the buildup of the forces in a given direction thus the device can be limited to the heating and mixing operations of the liquid metal fig2 shows an operating diagram of the installation when the inductors 13 and 14 are operated with an alternating current of the same voltage but phase shifted by 180 u00b0 in this case the magnetic field lines 19 originating from the cores 11 and 12 are elongated toward each other so that the transfer forces are eliminated and besides the heat effect a movement of the liquid perpendicular to the axis of the channels 4 and 6 and hence a mixing effect will be.