Integrated Buffer in Closed-Circuit Grinding Plant

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Solution Overview

Problem

Circular grinding systems for brittle materials face challenges in emptying dead volumes without external buffers, leading to inefficient operation and high energy costs due to the need for complex and expensive switching mechanisms.

Innovation Solution

Integration of a buffer within the grinding circuit, known as a bunker, which is part of the control loop, allows for continuous filling and emptying without additional height, reducing the need for external buffers and energy consumption by modifying the feeding device of the roller press to an overflow design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an external buffer is used to empty the dead volume of the circulation grinding system, then the system can be emptied for maintenance, but the device complexity and cost increase due to complex switching mechanisms

Engineering Contradiction:
Improveability to empty system for maintenanceVSAvoidcomplexity of switching mechanisms
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the buffer function directly into the circulation grinding system by integrating it with the classifier structure. The classifier housing serves dual purposes: as a classification device and as a buffer for ground material. This eliminates the need for separate external buffers and complex switching mechanisms, resolving the contradiction between system emptiability and device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The classifier housing is designed to perform multiple functions simultaneously: it acts as both a classification device for separating ground material and as a buffer for storing ground material. This multi-functionality eliminates the need for dedicated external buffer systems and their associated switching mechanisms, thereby reducing device complexity while maintaining the ability to empty the system for maintenance.

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

2Reliability

If the circulation grinding system is run empty to empty the dead volume, then the system can be emptied, but the roller press shows insufficient shredding effect and the material flow collapses

Engineering Contradiction:
Improveability to empty dead volumeVSAvoidshredding effect of roller press
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The integrated buffer stores ground material in advance within the classifier housing. When maintenance is needed, the buffer can be emptied first, allowing the circulation system to be stopped and emptied without running the roller press at insufficient load. This preliminary storage action prevents the collapse of material flow and maintains productive shredding operation until the buffer is ready to be emptied.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If an external buffer is connected to the circulation grinding system, then the dead volume can be emptied, but additional height and space are required for the buffer and switching mechanisms

Engineering Contradiction:
Improveability to empty dead volumeVSAvoidheight of grinding system
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent combines the buffer function with the existing classifier housing structure. By utilizing the classifier housing as both a classification device and a buffer, the design eliminates the need for separate external buffers that would increase system height. The integrated buffer occupies space that would otherwise be unused or require additional vertical clearance.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The classifier housing is designed to utilize horizontal space more effectively by creating an integrated buffer zone within the existing classifier structure. This dimensional reorganization allows the buffer to be accommodated without increasing the overall vertical height of the grinding system, as the buffer volume is integrated into the classifier's footprint rather than requiring additional vertical clearance.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 solution eliminates the need for external buffers, reduces the overall height of the grinding system, and saves energy by integrating the buffer into the control loop, ensuring efficient operation and material flow without complex switching mechanisms.

Implementation Method 1

the feeding device for the roller press is designed as an overflow, whereby only as much regrind is fed into the feeding device per unit of time so that the fill level in the feeding device remains as constant as possible

Methodology Applied
Scientific EffectOverflow:

Implementation Method 2

The milled material remaining when maintaining the filling state then runs through an overflow in the feeding device and falls from there next to the roller press and a deagglomeration device arranged underneath into a bunker

Methodology Applied
Scientific EffectAccumulation:

Data Source

PatentEP2582455B1Closed-circuit grinding plant having an integrated buffer
Publication Date: 2014.03.19 KHD HUMBOLDT WEDAG GMBH
  • EP2582455B1 patent drawingFigure 1

AI summary

The invention relates to a closed-circuit grinding plant for comminuting material to be ground, in which at least one comminution apparatus (RP) and at least one apparatus for separating comminuted material (8, 10) are connected to each other and keep the brittle material to be ground in the grinding circuit until it is removed from the grinding circuit by the separating device (10) on account of the level of comminution, wherein a control loop controls the feed of fresh material to be ground into the circuit, and also relates to a corresponding method for operating such a closed-circuit grinding plant. According to the invention, a buffer (2) for the material to be ground is present in the grinding circuit. The integration of the buffer (2) enables a reduced overall height of the closed-circuit grinding plant, which saves energy costs. The filling level of the integrated buffer (2) is suitable for controlling the closed-circuit grinding plant.