Abstract: The method of monitoring the level of filling of a ball mill which is fed with material to be pulverized and is provided with a drum mounted to rotate on two bearings which are relatively far apart, consists in measuring the weight of the drum using strain gauge weight sensors (11-16) under the bearings supporting the drum of the ball mill and comparing the measured weight to a predefined set point value to regulate the feeding of material to be pulverized to the ball mill. In addition, before the comparison step, the measured weight is corrected by a first weight value (Fv) representative of the vertical component of the force created by the torque driving rotation of the drum.

Abstract: A device for continuously measuring the quantity of coal inside a ball grinder including an ultrasound wave or electromagnetic wave emitter and a wave receiver. The emitter and the receiver are disposed so that the wave passes through at least part of the interior of the grinder. The receiver is associated with an electronic circuit for deducing the quantity of coal by comparing the signal received with data obtained from previous calibration measurements.

Abstract: The present invention concerns a device for monitoring a ball grinder having a cylindrical casing containing a mass of balls which, when the grinder is rotating at its nominal speed, takes up a position between two generatrices (1.sub.b, 1.sub.b') spaced by an angle between a minimal angle .alpha..sub.min and a maximal angle .alpha..sub.max and a mass of coal which, when the grinder is rotating at its nominal speed, takes up a position between two generatrices (1.sub.c, 1.sub.c') spaced by an angle .beta.. An electromagnetic wave emitter is disposed inside the grinder and at least one wave receiver is disposed outside the grinder. The receiver is associated with an electronic circuit for determining at least one parameter of the grinder selected from the quantity of balls, the quantity of coal and the wear of the cylinder.