Rotatable Screen Cloth for Continuous Ball Mill Screening

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Solution Overview

Problem

Existing screening methods for dry source material in industrial scale and continuous processes face energy inefficiency due to repeated passes through ball mills and separators, and dust accumulation hampers further grinding.

Innovation Solution

A screening device with a rotatable screen cloth and declogging nozzles that allows continuous screening and removal of larger particles using compressed air, integrated within a ball mill, preventing clogging and enhancing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If dry source material is ground in a ball mill and separated using a separator, then fine particles and coarse particles can be separated, but energy is consumed excessively when material must pass through the ball mill and separator multiple times

Engineering Contradiction:
Improveenergy consumptionVSAvoidscreening efficiency
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The invention combines the ball mill and screening device into a single integrated system. The screening device is positioned inside the ball mill chamber, allowing simultaneous grinding and screening operations. This eliminates the need for separate passes through external separators and prevents dust accumulation by continuously removing fine particles during the grinding process, thereby reducing energy consumption while maintaining productivity.

Inventive Principle:
Principle #5Merging (Combining)

2Productivity

If a screen cloth is used to separate particles, then screening can be performed, but the screen cloth becomes clogged with dust accumulation preventing further grinding

Engineering Contradiction:
Improvecontinuous screening capabilityVSAvoidscreen cloth clogging
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention incorporates a reverse jet system that periodically blows compressed air through the screen cloth in the opposite direction of normal particle flow. This preliminary cleaning action prevents dust accumulation and clogging before they can impede the screening process, ensuring continuous operation and maintaining reliability of the screening function.

Inventive Principle:
Principle #10Preliminary action

3Ease of repair

If a cylindrical screen with high-pressure jets is used to remove clogged material, then screen cleaning is achieved, but the device complexity increases

Engineering Contradiction:
Improvescreen declogging capabilityVSAvoiddevice structure
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The invention uses compressed air jets directed through the screen cloth to remove clogged material. The pneumatic system provides effective screen cleaning without requiring complex mechanical scraping or reverse-rotation mechanisms. The compressed air is delivered through simple nozzle structures positioned on the interior of the screen, maintaining device simplicity while achieving reliable declogging capability.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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

Enables continuous screening without reprocessing, reducing energy consumption and dust accumulation, thereby improving the grinding process efficiency.

Implementation Method 1

a declogging nozzle (136, 137) configured to direct a flow of compressed air from the inlet (122) against the screen cloth (115)

Methodology Applied
Scientific EffectCompressed air flow: Jet

Data Source

PatentEP4265344B1Screening device, screening system and screening method
Publication Date: 2025.09.24 ECOUP OY
  • EP4265344B1 patent drawingFigure 1
  • EP4265344B1 patent drawingFigure 2
  • EP4265344B1 patent drawingFigure 3

AI summary

A screening device (100) is disclosed. The screening device comprises a screen cloth (115) for separating a screened fraction, a perforated support structure (110, 111) for supporting the screen cloth (115), an outlet (120) for the screened fraction and an inlet (122) for compressed air. The screening device further comprises a declogging nozzle (136, 137) and an air conduit (130, 131) extending between said inlet (122) and said declogging nozzle (136, 137) for blowing compressed air against the screen cloth (115). The perforated support structure (110, 111) and the screen cloth are rotatable in relation to the declogging nozzle (136, 137). Also a screening system and a screening method are disclosed.