Roller Grinding Mill Distributed Drive Radial Force Management

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Solution Overview

Problem

Modern roller mills face challenges with drive system maintenance, as issues in one component require complete drive removal, leading to long procurement times for replacement parts and inefficiencies in multi-motor drive concepts due to torque overshoots and reduced availability.

Innovation Solution

The roller mill design features a grinding table driven by multiple distributed drives around its circumference, with grinding rollers mounted on rocker arms for individual removal and adjustable angular positions to minimize radial forces, allowing for decoupling of drives and compensation by remaining rollers to maintain capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single drive is deactivated for maintenance, then maintenance availability is improved, but a large radial force component acts on the grinding table bearing

Engineering Contradiction:
Improvemaintenance availabilityVSAvoidradial force component on bearing
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The invention makes the angular position of the drives adjustable around the center of the mill. When a drive is deactivated for maintenance, the angular position of the remaining active drives can be dynamically changed to optimize the force distribution. This dynamic adjustment allows the system to adapt to the reduced number of active drives, minimizing the radial force component on the bearing while maintaining maintenance availability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the operational parameters by allowing adjustment of the angular positions of the drives. By modifying the angular position parameter, the system can compensate for the deactivation of a single drive, ensuring that the resultant radial force on the bearing remains minimal even when maintenance is performed on one drive.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If multiple distributed drives are used around the grinding table, then maintenance availability and radial force minimization are improved, but device complexity increases

Engineering Contradiction:
Improvemaintenance availabilityVSAvoiddrive system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention divides the drive system into multiple independent drives distributed around the grinding table. Each drive can be independently deactivated and maintained without affecting the others, improving maintenance availability. The segmentation allows one drive to be taken offline while the others continue operation, reducing system downtime.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The adjustable angular position mechanism adds dynamic capability to the drive system. This allows the system to adapt its configuration based on operational needs, such as optimizing force distribution when drives are deactivated for maintenance. The dynamic adjustment capability resolves the complexity issue by providing flexibility that simplifies maintenance operations.

Inventive Principle:
Principle #15Dynamics

3Ease of repair

If grinding rollers are mounted on rocker arms for individual removal, then ease of repair is improved, but device complexity increases

Engineering Contradiction:
Improvegrinding roller accessibilityVSAvoidmounting mechanism complexity
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The invention segments the grinding roller mounting system by attaching each roller to an individual rocker arm. This segmentation allows each roller to be independently manipulated and removed without affecting other rollers. The modular rocker arm design simplifies repair operations by providing easy access to individual rollers while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of fixing the grinding rollers rigidly to the grinding table, the invention inverts the approach by mounting rollers on rocker arms that can swing outward. This inversion of the mounting concept allows rollers to be easily accessed and removed by swinging them outward on the rocker arms, significantly improving ease of repair with minimal structural complexity.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP2252403B1Roller grinding mill
Publication Date: 2014.07.02 GEBR PFEIFFER SE
  • EP2252403B1 patent drawingFigure 1
  • EP2252403B1 patent drawingFigure 2a~2d
  • EP2252403B1 patent drawingFigure 3a~3d

AI summary

The invention relates to roller grinding mills comprising a grinding plate (1), grinding rollers (M), and at least two drives (A) acting upon the grinding plate (1), and to a method for operating such a roller grinding mill. At least one grinding roller and simultaneously at least one matching drive (A) can be disengaged during operation. Thus only small radial forces are created that effect the radial bearing of the grinding plate (1).