Attritor Mill Rotor Layout for Organic Waste Grinding Flow

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Solution Overview

Problem

Existing attritor mills are inefficient in processing organic waste, plastics, and fibrous materials due to suboptimal material flow and pebble/ball movement within the grinding chamber.

Innovation Solution

The attritor mill design includes a rotor with radially extending arms of varying lengths, supporting protrusions on the bottom wall, and blades to enhance material flow and pebble/ball movement, along with adjustable outlet actuators for optimized granulometry and easy maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional attritor mill design is used, then structure is simple, but material flow efficiency is poor

Engineering Contradiction:
Improvematerial flow efficiencyVSAvoidrotor structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The rotor is segmented into multiple arms of varying lengths arranged at different radial positions, with each arm having specific grinding bodies attached. This segmentation creates multiple impact zones and flight paths for the grinding bodies, significantly improving material flow efficiency and grinding effectiveness while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The rotor arms are designed with asymmetric length configurations, where arms at different radial positions have different lengths. This asymmetry creates varied impact trajectories and energy distribution patterns, enhancing material processing efficiency by preventing uniform wear and optimizing the grinding action across different zones of the chamber.

Inventive Principle:
Principle #4Asymmetry

2Productivity

If traditional attritor mill design is used, then device is simple, but pebble/ball movement is insufficient

Engineering Contradiction:
Improvegrinding kineticsVSAvoidgrinding chamber structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Supporting protrusions are pre-installed on the chamber floor at strategic positions to guide and enhance pebble/ball flight paths. These protrusions are positioned to intercept grinding bodies mid-air and redirect them toward optimal impact zones, preliminarily shaping the movement trajectories before the grinding action occurs.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The supporting protrusions act as intermediary elements between the rotating grinding bodies and the material on the chamber floor. These protrusions mediate the energy transfer by controlling the flight paths of pebbles and balls, ensuring they reach the material with optimal velocity and angle, thereby enhancing grinding kinetics without requiring complex chamber structures.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If traditional attritor mill design is used, then structure is simple, but material processing efficiency is low

Engineering Contradiction:
Improveprocessing efficiencyVSAvoidrotor and grinding chamber configuration
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Different regions of the grinding chamber are optimized with local quality variations. The rotor arms are positioned and dimensioned to create specific impact patterns in different radial zones, while supporting protrusions are strategically placed on the chamber floor to enhance material flow in specific areas. This localized optimization ensures efficient processing throughout the chamber without requiring complete structural complexity.

Inventive Principle:
Principle #3Local quality

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

Improves the efficiency of material processing by ensuring uniform particle size and enhanced pebble/ball flight, facilitating easier evacuation and reducing wear, thus enhancing the overall processing capacity and productivity.

Implementation Method 1

agitating the material to be treated and the plurality of grinding free bodies (19) by making the rotor (11) rotate on itself

Methodology Applied
Scientific EffectRotational motion:

Implementation Method 2

its first (15) and second arms (17) strike the grinding free bodies (19) and at least a part of said grinding free bodies (19) bounce against the walls of the grinding chamber (7) and other grinding free bodies (19), and/or strike the material to be treated

Methodology Applied
Scientific EffectImpact force: Impact Force

Implementation Method 3

at least one supporting protrusion (23) is provided on the bottom wall (21), each of which is configured for deviating mainly upwards the grinding free bodies (19) that strike the protrusion (23) itself

Methodology Applied
Scientific EffectMechanical deviation:

Implementation Method 4

the rotor (11) comprises one or more blades (25) each of which configured for cutting, mincing or chopping the material to be treated

Methodology Applied
Scientific EffectMechanical cutting:

Implementation Method 5

The attritor mill (1) can dry and dewater organic or other humid waste through squeezing the water contained in the waste under high pressure and vaporizing it tanks to the heat produced by friction in the grinding chamber

Methodology Applied
Scientific EffectFriction heating: Viscous Heating

Data Source

PatentEP4725610A2Attritor mill and process for processing a material therewith
Publication Date: 2026.04.15 ATTRITOR MILL LTD
  • EP4725610A2 patent drawingFigure 1
  • EP4725610A2 patent drawingFigure 2
  • EP4725610A2 patent drawingFigure 2A

AI summary

The attritor mill (1) according to the invention comprises a grinding container (5) and a rotor (11) comprises a plurality of arms (15, 17). The attritor mill (1) is configured for grinding, reducing, mincing or micronizing a material to be treated such as, for example, solid urban waste, food waste, mowing or pruning scraps, vegetable waste from agricultural activity, waste similar to urban waste, FOS ("dry organic fraction") of urban waste carrying out the following steps: D.1) mixing the material to be treated with a plurality of grinding free bodies (19) in the grinding chamber (7); D.2) agitating the material to be treated and the plurality of grinding free bodies (19) by causing the rotor (11)rotate on itself. At least one first arm (15) closest to the bottom wall (21) is shorter than at least one second arm (17) arranged above said first arm (15).