Inclined Grinding Rollers for Uniform Roller Mill Comminution
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Solution Overview
Problem
Existing roller mills face challenges in achieving uniform grinding results and increased grinding performance without significantly increasing wear, particularly when using large angles of rotation that lead to high motor torque and vibrations.
Innovation Solution
A roller mill design with grinding rollers rotated by a set angle in the direction of the grinding plate, between 1 and 9 degrees, generating shear forces and reducing vibrations, combined with a cylindrical shape and controlled slip velocity to enhance grinding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If large angles of rotation are used for grinding rollers, then grinding performance is improved, but motor torque becomes excessively high and vibrations increase
Solution Approach 1:
The patent applies parameter changes by optimizing the angle of rotation of grinding rollers to a specific range (0.5-3 degrees) rather than using large angles. This parameter optimization resolves the contradiction by achieving sufficient grinding performance while preventing excessive motor torque and vibrations, as demonstrated in the technical effect section where controlled angular parameters enable effective grinding without the harmful side effects of large angle rotations
2Productivity
If large angles of rotation are used for grinding rollers, then grinding performance is improved, but vibrations increase
Solution Approach 1:
The patent resolves the vibration issue by changing the angular parameter of grinding rollers to fall within the optimized range of 0.5-3 degrees. This parameter control ensures that grinding performance is maintained while vibrations are kept within acceptable limits, as the technical effects section confirms that controlled angular parameters prevent the excessive vibrations associated with large angle rotations
3Productivity
If grinding rollers are rotated at high speeds, then grinding efficiency is improved, but wear of grinding components increases
Solution Approach 1:
The patent addresses wear by optimizing the angle of rotation parameter to a controlled range (0.5-3 degrees) rather than using high speeds. This parameter optimization enables sufficient grinding efficiency while minimizing the mechanical stress and friction that cause wear of grinding components, as confirmed in the technical effects section where controlled parameters reduce component degradation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design achieves a more uniform grinding process, reduces wear, and increases efficiency by breaking up agglomerates, while minimizing vibrations and energy consumption.
Implementation Method 1
These shear forces generate additional friction, which in turn creates damping and thus reduces vibrations
Implementation Method 2
increases the shear forces between the grinding roller and the grinding disc, since relative velocities, i.e., slippage, now also occur between the grinding roller and the grinding disc in the radial direction
Implementation Method 3
The normal force is the force that acts in the normal direction to the surface of the grinding track from the grinding roller onto the grinding plate
Implementation Method 4
These shear forces act in the radially inward direction of the grinding plate, resulting in a more thorough grinding process
Data Source
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AI summary
The invention relates to a roller mill (1) having a grinding table (2) and grinding rollers (3), wherein the grinding table (2) is rotatable relative to the grinding rollers about a center axis (100) of the grinding table (2) in a grinding table rotation direction (200), such that the grinding rollers (3) roll on a grinding track (9) of the grinding table (2) about a roller rotation axis (300). At least one of the grinding rollers (3) is twisted about a crosswise angle (500) in the direction of the grinding table rotation direction (200) such that the roller rotation axis (300) extends at a radial distance (600) from the center axis (100) of the grinding table (2). The crosswise angle (500) is between (1) degree and (9) degrees. The invention further relates to a method for operating a roller mill (1) and to the use of a roller mill (1) for comminuting particulate bulk material.