Roller Mill Table Wear Reduction via Velocity Matching
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Solution Overview
Problem
In roller mills, uneven circumferential velocities between the roller and the rotary table lead to differential wear patterns, making table repair more frequent and complex, while roller repair is relatively easier. To minimize table wear and reduce repair frequencies, the design must address these velocity disparities.
Innovation Solution
The roller mill is configured with a first contact position where the roller's circumferential velocity equals the table's velocity located further inward, and a constant roller curvature, with a dam ring to manage fuel discharge and an adjustment mechanism to maintain grinding efficiency as wear progresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the roller and table are designed with conventional contact positioning, then the grinding function is maintained, but uneven wear occurs on the table requiring frequent repair
Solution Approach 1:
The patent applies local quality by creating a non-uniform circumferential velocity distribution on the table surface through variable radius curvature design. Different regions of the table have different radii of curvature, which creates zones with different linear velocities at the contact point with the roller. This localized variation in velocity characteristics allows specific regions to experience reduced wear rates, thereby improving overall table wear resistance and reducing repair frequency.
Solution Approach 2:
The patent implements parameter changes by modifying the geometric parameters of the table surface, specifically the radius of curvature, as a function of position. The radius of curvature varies along the circumferential direction, which directly changes the linear velocity parameter at different contact points. This parameter variation strategy transforms the uniform wear pattern into a controlled non-uniform wear pattern that extends table service life.
2Reliability
If the roller circumferential velocity is increased to match table velocity at all positions, then wear is uniform, but the roller design becomes complex
Solution Approach 1:
The patent applies asymmetry by designing the table with non-uniform radius of curvature, creating an asymmetric velocity distribution pattern. Instead of attempting to make the roller velocity match the table velocity at all positions (which would require complex asymmetric roller design), the solution asymmetrically modifies the table geometry to create favorable velocity zones that reduce wear without requiring complex roller modifications.
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
This configuration reduces table wear, decreases repair frequencies, and maintains grinding efficiency by distributing wear uniformly and preventing fuel accumulation issues, thus extending the service life of both the roller and the table.
Implementation Method 1
a roller (13) that rotates about a rotating shaft (21) by being pressed against a grinding surface (12c) of the rotary table (12) and grinds the solid fuel along with rotation of the rotary table (12)
Data Source
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AI summary
Provided is a roller mill that is provided with: a rotary table (12); a raw coal adding tube that supplies solid fuel to the rotary table (12); and a roller (13) that rotates about a rotating shaft (21) by being pressed against a grinding surface (12c) of the rotary table (12) and grinds solid fuel along with rotation of the rotary table (12). In such a roller mill, a position (P1) where an outer peripheral surface (13a) of the roller (13) and the grinding surface (12c) of the rotary table (12) come into contact with each other and a circumferential velocity of the outer peripheral surface (13a) equals a circumferential velocity of the grinding surface (12c) is located further to an inner circumferential side of the rotary table (12) than a position (P2) where the outer peripheral surface (13a) and the grinding surface (12c) come into contact with each other at a center position in a width direction of the roller (13).