Curved Ceiling Grate Hammer Mill Ejection Efficiency

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Solution Overview

Problem

Existing hammer mills face issues with material accumulation on the top grate due to low kinetic energy particles and the risk of fire from hot metal pieces contacting deposits, particularly with flat top grates, which restricts their application in recycling processes.

Innovation Solution

The hammer mill features a curved ceiling grate with an inclination of at least 10°, a honeycomb structure, and a pivoting grate flap, ensuring efficient material ejection into the chute and preventing accumulation, along with an exhaust air extraction system and a detachable upper part for easy maintenance and component replacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a flat top grate is used, then the structure is simple and easy to manufacture, but material accumulates on the grate surface reducing ejection efficiency

Engineering Contradiction:
Improveease of manufactureVSAvoidejection efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The top grate is designed with a curved surface instead of a flat one. The curvature causes ground material pieces to roll off the grate surface more effectively toward the ejection chute, preventing accumulation and improving ejection efficiency while maintaining structural simplicity

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Productivity

If the top grate is curved to improve material ejection, then ejection efficiency improves, but the structural complexity increases

Engineering Contradiction:
Improveejection efficiencyVSAvoidstructural complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The top grate employs a curved surface geometry that leverages gravity and rolling motion to enhance material ejection. The curvature is designed to guide material flow naturally without requiring additional mechanical components, thus improving productivity while limiting the increase in structural complexity

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Productivity

If a curved ceiling grate is used, then material accumulation is reduced and ejection is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvematerial flow efficiencyVSAvoidease of manufacture
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The ceiling grate is formed with a curved surface that optimizes material flow and prevents accumulation. The curvature is designed to work with the natural motion of ground material, improving ejection efficiency while the manufacturing process is adapted to produce this curved geometry efficiently

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Productivity

If the top grate is inclined towards the ejection chute, then material ejection is enhanced, but the risk of hot metal pieces contacting deposits increases

Engineering Contradiction:
Improveejection efficiencyVSAvoidfire risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The curved surface of the top grate creates a rolling motion for material pieces as they move toward the ejection chute. This continuous motion reduces the residence time of hot metal pieces on the grate surface, minimizing the opportunity for contact with accumulated deposits and reducing fire risk while maintaining ejection efficiency

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

The solution enhances material ejection efficiency, prevents fire risks, and expands the hammer mill's application in recycling by ensuring consistent material flow and safe operation, while allowing for flexible configuration and easy maintenance.

Implementation Method 1

ejected pieces of the ground material which penetrate the ceiling grate always fall into the ejection chute under the force of gravity

Methodology Applied
Scientific EffectGravity: Gravitation

Implementation Method 2

The honeycomb structure improves the elasticity and stability of the ceiling grid

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3858488A1Hammer mill
Publication Date: 2021.08.04 ALBERT HOFFMANN GMBH
  • EP3858488A1 patent drawingFigure 1
  • EP3858488A1 patent drawingFigure 2a~2c
  • EP3858488A1 patent drawingFigure 3

AI summary

A hammer mill (1) is disclosed, comprising a feeding device (4) for feeding a working chamber (5) inside the hammer mill (1) with a material to be ground. The working chamber (5) is covered at one end by a grate (12) made of manganese steel, and a discharge chute (10) is connected to the grate for pieces of the material to be ground that are ejected from the working chamber (5) through the grate (12). A rotor with a plurality of movable hammers is rotatably mounted about a horizontal axis (7) in the working chamber (5), which crush the material to be ground and convey it through the working chamber (5). The grate (12) is curved towards the discharge chute (10). To extend the range of application of the hammer mill (1), it is proposed that the curvature describe a circular arc around an edge (14) of the working chamber (5).