Roller Mill Baffle for Particle Recirculation Control

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Solution Overview

Problem

Existing roller mills face inefficiencies due to the recirculation of oversized particles between the grinding chamber and classifier, which reduces mill capacity and increases noise, and existing solutions require complex and costly external return paths that are prone to clogging and non-uniform particle distribution.

Innovation Solution

A baffle is introduced within the mill housing to create a separate annular passage for oversized particles, directing them downward to the grinding mechanism while minimizing the influence of upward airflow, thereby reducing recirculation and ensuring a more uniform distribution around the grinding ring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If oversized particles are allowed to recirculate between grinding chamber and classifier, then particle separation is achieved, but mill capacity decreases and efficiency lowers

Engineering Contradiction:
Improveparticle separationVSAvoidmill capacity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the particle flow paths by introducing a baffle that divides the grinding chamber into separate zones. The baffle creates distinct flow channels for fine particles (upward through classifier) and oversized particles (downward to grinding rollers), preventing mixing and recirculation of rejected particles while maintaining efficient separation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The baffle acts as an intermediary element between the classifier and grinding chamber. It mediates the particle flow by providing a physical barrier that redirects oversized particles downward to the grinding rollers while allowing fine particles to continue upward to the classifier, thus eliminating harmful recirculation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If external return paths are used for oversized particles, then recirculation is reduced, but device complexity and cost increase

Engineering Contradiction:
Improverecirculation reductionVSAvoidreturn path structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges the return path function into the existing mill housing structure by using a baffle that is integrated into the side wall. This eliminates the need for separate external conduits and return paths, reducing structural complexity while still achieving the goal of directing oversized particles back to the grinding rollers.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The baffle structure serves multiple functions simultaneously: it acts as a flow separator, a particle redirector, and a structural component of the mill housing. This multi-functionality eliminates the need for additional dedicated return path components, simplifying the overall device structure.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If oversized particles are funneled through conduits, then return path is created, but particle distribution becomes non-uniform and clumping occurs

Engineering Contradiction:
Improvereturn path creationVSAvoidparticle distribution uniformity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The baffle creates locally optimized flow conditions at different positions within the grinding chamber. By strategically positioning the baffle and its openings, the patent ensures uniform particle distribution in the grinding zone while maintaining easy operation through the return path function.

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

This design enhances grinding efficiency by preventing the recirculation of oversized particles and maintaining a uniform particle distribution, leading to improved mill capacity and reduced noise, while avoiding the complexity and cost of external return paths.

Implementation Method 1

The classifier includes a rotor having a plurality of blades disposed within a classifier housing defining a classifying chamber. The rotor rotates to separate fine sized particles from oversized particles

Methodology Applied
Scientific EffectCentrifugal separation: Centrifugal Separation

Implementation Method 2

The outer annular passage receives and directs the oversized particles downward to the grinding mechanism of the mill

Methodology Applied
Scientific EffectGravitational flow: Gravitation

Data Source

PatentEP2222407B1Fine grinding roller mill
Publication Date: 2023.07.26 SCHENCK PROCESS LLC
  • EP2222407B1 patent drawingFigure 1
  • EP2222407B1 patent drawingFigure 2
  • EP2222407B1 patent drawingFigure 3~8

AI summary

A roller mill (40) is provided for crushing a material with a classifier (44) disposed on the mill (40) for separating the crushed material. The mill (40) includes a grinding mechanism (64, 66) that has a plurality of grinding rolls (64) and a grinding ring (66) that coact to pulverize material within a mill housing (48), which defines a grinding chamber (54). The classifier (44) is a centrifugal-type classifier having a motor-driven rotor (70) disposed within a classifier housing (74), which define a classifying chamber (80). The rotor (70) has a plurality of blades (72) that extend outwardly from the rotor (70). As the rotor (70) rotates within the classifying chamber (80), the blades (72) separate fine sized particles from oversized particles by passing the finer sized particles through the blades (72), and contacting and propelling the oversized particles against the classifier housing (74). The oversize particles fall downward through an outer annular passage (104) defined by a baffle (100) and the mill housing (48) back to the grinding mechanism (64, 66).