Patent ID: 7669517

Claim:
An appliance for preparing a froth from milk or a milk-based liquid, comprising: a tank for receiving the liquid that is to be frothed, in which liquid a rotatable stirrer is positioned, the tank having a median vertical axis and a bottom; a stand associated with the tank; a mechanism for driving the stirrer, a heating device associated with the tank for heating the liquid in the tank and a first controller for activating the heating device during stirring, an electrical power supply for electrically powering the driving mechanism; wherein the driving mechanism and the stirrer are configured in such a way that the stirrer is driven by the driving mechanism through a magnetic drive effect in order to generate the froth, without a mechanical connection member intruding through the wall of the tank; and at least one disturbance member comprising a magnetic driver that produces at least one magnetic field that is offset with respect to the median vertical axis of the tank, and means for positioning the stirrer along an axis of rotation that is offset with respect to the median vertical axis of the tank to enable magnetic engagement of the stirrer along this rotational axis, and a controller configured in such a way as to drive the magnetic driver to thereby magnetically drive the stirrer at a speed that is sufficiently high to convert the liquid into the froth as it is being heated, wherein the disturbance member breaks or prevents symmetric circulation of the liquid about the median vertical axis of the tank.