Roller mill and method for controlling a roller mill
AssigneeABB Schweiz AG
InventorsMartin Pischtschan, Hans-Ulrich Hirt
Life of this patent
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Abstract
The subject matter of the invention is a roller mill comprising two rollers which are arranged in parallel, are pressed one against the other and rotate in opposite directions, wherein one of the rollers can be displaced orthogonally with respect to the axial direction of this roller, and two drives, which drives are each assigned to one of the two rollers, and each have an electric motor, a master of the electric motors predefines for the electric motors a setpoint value for the rotational speed of the torque as a reference, and a reference of a follower electric motor of the electric motors comprises the actual value of the torque or of the rotational speed of the master electric motor multiplied by a load distribution factor.
Claims6
A roller mill for milling materials including ores and cement, comprising
- two rollers which are arranged in parallel, are pressed one against the other and rotate in opposite directions during operation in order to mill the material between the two rollers, wherein
- one of the rollers can be displaced orthogonally with respect to an axial direction of the one of the rollers,
- a master electric motor and a follower electric motor, the master electric motor driving one of the rollers and the follower electric motor driving another of the rollers,
- a first controller of the master electric motor configured to receive a setpoint value for a rotational speed or a torque as a first reference for a control of the master electric motor, the first reference being a target value of the control,
- a multiplier configured to multiply an actual value of the torque or of the rotational speed of the master electric motor by a load distribution factor, the load distribution factor being a variable value selected for influencing a wear difference of the two rollers, and
- a second controller of the follower electric motor configured to receive a second reference for a control of the follower electric motor, the second reference being a target value of the control, the second reference being based on a value which arises as a result of multiplication of the multiplier,
- wherein the load distribution factor is different from 1 at least part of the time such that the torque or the rotational speed of the master electric motor and the follower electric motor are different from each other and the wear caused by the material milled between the two rollers is varied.
A roller mill for milling materials including ores and cement, comprising
- two rollers which are arranged in parallel, are pressed one against the other and rotate in opposite directions during operation in order to mill the material between the two rollers, wherein one of the rollers can be displaced orthogonally with respect to an axial direction of the one of the rollers,
- a master electric motor and a follower electric motor, the master electric motor driving one of the rollers and the follower electric motor driving another of the rollers,
- a first controller of the master electric motor configured to receive a setpoint value for a rotational speed or a torque as a first reference for a control of the master electric motor, the first reference being a target value of the control,
- a multiplier configured to multiply an actual value of the torque or of the rotational speed of the master electric motor by a load distribution factor, the load distribution factor being a variable value selected for influencing a wear difference of the two rollers, and wherein the actual value of the torque or of the rotational speed of the master electric motor multiplied by the load distribution factor with the multiplier is compared with a corresponding actual value of the follower electric motor via a subtraction with a subtraction unit;
- and
- a second controller of the follower electric motor configured to receive a second reference for a control of the follower electric motor, the second reference being a target value of the control, the second reference being based on a value which arises as a result of the subtraction with an addition of the first reference,
- wherein the load distribution factor is different from 1 at least part of the time such that the torque or the rotational speed of the master electric motor and the follower electric motor are different from each other and the wear caused by the material milled between the two rollers is varied.
Dependencies are inferred from the claim text.