Pivotable Grinding Tool for Whirlpool Mill Foreign Body Impact

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Solution Overview

Problem

Whirlpool mills experience high downtimes and risk of grinding tool breakage due to foreign objects and material abrasion, leading to increased operating costs and safety risks.

Innovation Solution

A pivotable or oscillating grinding tool attached to the rotor with an inclined crushing surface, allowing it to pivot out of its working position when encountering hard foreign bodies, reducing impact and converting impact energy into sliding motion, and using materials like ceramic or stainless steel depending on the material being ground.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the grinding tool is fixed rigidly to the rotor, then the grinding efficiency is improved, but the risk of tool breakage and damage increases when encountering foreign bodies

Engineering Contradiction:
Improvegrinding efficiencyVSAvoidrisk of tool breakage
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The grinding tool is designed to be pivotably mounted on the rotor instead of being rigidly fixed. The pivot axis is arranged substantially perpendicular to the rotation axis of the rotor. During normal operation, centrifugal force keeps the tool in its working position for effective grinding. When a foreign body is encountered, the tool can pivot away from its working position to avoid damage, thus resolving the contradiction between maintaining grinding efficiency and preventing tool breakage.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the grinding tool is made detachable or pivotable, then the risk of damage from foreign bodies is reduced, but the device complexity increases

Engineering Contradiction:
Improverisk of damage from foreign bodiesVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The mounting structure provides a simple pivot mechanism with a pivot axis perpendicular to the rotor rotation axis. This dynamic mounting allows the tool to automatically adjust its position in response to foreign bodies without requiring complex control systems or multiple components. The simplicity of the pivot mechanism minimizes the increase in device complexity while achieving the reliability benefit.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The angle of the crushing surface relative to the radial plane is optimized to balance grinding performance and foreign body avoidance. By carefully selecting this geometric parameter, the tool achieves effective material processing while maintaining the ability to pivot away from damaging impacts, thus reducing the need for additional protective mechanisms.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the crushing surface is inclined at a larger angle, then the impact energy from foreign bodies is better converted to sliding motion, but the grinding efficiency decreases

Engineering Contradiction:
Improveimpact energy conversionVSAvoidgrinding efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The angle of inclination of the crushing surface relative to the radial plane is optimized within a specific range. This parameter optimization ensures that impact energy from foreign bodies is effectively converted into sliding motion, reducing tool damage, while maintaining sufficient grinding efficiency for effective material processing.

Inventive Principle:
Principle #35Parameter changes

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 design reduces the risk of grinding tool breakage and damage, allowing for safer operation and lower maintenance costs by enabling the mill to be shut down before further damage occurs, and optimizing material usage with a separate, simpler fastening section.

Implementation Method 1

the material to be ground is fed in from above and centrifuged outwards in a gap between the rotor and a cover of the housing

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

it has surprisingly turned out that despite the high speeds and peripheral speeds that are usual in cyclone mills, destruction can be avoided by pivoting the grinding tool out of its working position and thereby being able to avoid hard foreign bodies

Methodology Applied
Scientific EffectImpact force: Impact Force

Implementation Method 3

part of the impact energy is converted into a sliding movement along the angle of inclination and thus into friction

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2052778B1Whirlpool mill and grinding tool and grinding ring for same
Publication Date: 2015.07.01 LEHIGH TECH INC
  • EP2052778B1 patent drawingFigure 1~2
  • EP2052778B1 patent drawingFigure 3
  • EP2052778B1 patent drawingFigure 4~5

AI summary

The grinding tool (201) has a mill gap for mounting at a rotor and the mill gap is defined between a stator and the rotor. A refractive surface (203) is provided that points towards the rotational direction. The grinding tool is fastened around swivel axis swiveling at the rotor and parallel to the rotational axis of the rotor. An independent claim is included for a grinding ring for receiving a grinding tool and for attachment at a rotor of a whirlpool mill with a grinding gap defined between a stator and the rotor.