Roller Mill Mode Switching via Independent Motor Speed Control

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Solution Overview

Problem

Conventional roller mills face challenges in efficiently switching between different operating modes due to fixed speed ratios, leading to increased production and operating costs, as they require stopping and reorienting rollers to change modes, which is cumbersome and energy-intensive.

Innovation Solution

The roller mill design incorporates two electrical machines with different power ratings and frequency converters, allowing for adjustable speed control during operation, enabling seamless transitions between modes without stopping, and utilizing a power coupler to optimize energy usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional roller mills use fixed speed ratios with a common motor, then the device complexity is reduced, but the adaptability between operating modes (cutting-cutting and back-back) deteriorates

Engineering Contradiction:
Improveadaptability between operating modesVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The common motor is segmented into two separate motors, each independently controlling one roller. This allows independent speed adjustment of each roller, enabling flexible switching between cutting-cutting and back-back operating modes without increasing overall system complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from fixed speed ratios to dynamic, independently adjustable speeds. Each motor can be controlled to provide different rotational speeds to each roller, allowing the system to adapt to different operating requirements and grain types in real-time

Inventive Principle:
Principle #15Dynamics

2Productivity

If roller mills require stopping and reorienting rollers to change operating modes, then the device complexity remains low, but the productivity and loss of time increase

Engineering Contradiction:
ImproveproductivityVSAvoidloss of time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The roller mill can switch between cutting-cutting and back-back operating modes while continuing to grind grain. The independent motor control allows seamless transition between modes without stopping the rollers, maintaining continuous productive action and eliminating downtime

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system uses dynamic speed adjustment through independent motors to change operating modes during operation. By varying the rotational speeds of individual rollers, the system can transition between modes without mechanical reorientation or stopping, thus avoiding time loss

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If roller mills use a common motor with fixed transmission ratio, then the manufacturing cost is reduced, but the ease of operation and speed adjustment capability deteriorate

Engineering Contradiction:
Improveease of operationVSAvoidease of manufacture
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The single common motor is segmented into two separate motors with independent control. Each motor can be independently adjusted to provide optimal speeds for different grain types and operating modes, significantly improving ease of operation despite the additional manufacturing component

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system enables continuous parameter changes in rotational speed for each roller independently. This allows operators to easily adjust speeds to optimize grinding performance for different grains, making the system more versatile and easier to operate across various applications

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3127614B2Roller mill with cutting cutting operating type and back back operating type
Publication Date: 2020.11.18 ING STEFAN KASTENMULLER GMBH
  • EP3127614B2 patent drawingFigure 1a~1b
  • EP3127614B2 patent drawingFigure 2
  • EP3127614B2 patent drawingFigure 3a~3b

AI summary

The invention relates to a roller mill (10) with a first corrugating roller (12) having a plurality of first corrugating edges (32) and first corrugating backs (34), and with a second corrugating roller (14) having a plurality of second corrugating edges (36) and second corrugating backs (38). The roller mill can be operated in an edge-to-edge mode, in which the first edges and the second edges are brought close together, and in a back-to-back mode, in which the first backs and the second backs are brought close together. A change between the edge-to-edge mode and the back-to-back mode can be effected during operation by changing the rotational speed of the first corrugating roller and/or a change in the rotational speed of the second corrugating roller.