Bulk Density Determination in Mobile Crusher Conveyors

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Solution Overview

Problem

Existing methods for determining bulk material weight and volume on a conveyor belt in mobile crushers are sensitive to environmental conditions, leading to unreliable measurements due to disruptions like dust and temperature changes, requiring frequent calibration and a constant bulk material density for accurate long-term operation.

Innovation Solution

The method continuously records bulk material weight and volume, determining bulk density as their quotient, using it as a control and correction value, and outputs an interference signal when deviations occur, allowing for real-time adjustment and correction of measurements, even when environmental conditions change.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional belt scales are used for direct weight measurement, then weight can be measured directly, but the system requires frequent calibration due to changing environmental conditions

Engineering Contradiction:
Improveweight measurement accuracyVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent introduces bulk material density as an intermediary parameter to bridge volume measurement and weight determination. Instead of directly measuring weight with prone-to-drift scales, the system measures volume optically and uses density (determined from initial calibration runs) as a mediator to calculate weight, thereby avoiding frequent scale recalibration while maintaining measurement accuracy

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical belt scale system with an optical scanning system for volume measurement combined with density-based calculation. This substitution eliminates the mechanical sensors that are sensitive to environmental conditions like temperature and vibration, replacing them with optical methods that are more stable and require less frequent calibration

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If volume determination is used to calculate weight, then direct weight measurement is avoided, but volume determination is sensitive to environmental conditions like dust and water droplets

Engineering Contradiction:
Improveweight determination accuracyVSAvoidmeasurement reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements feedback by continuously monitoring bulk material density and comparing it against reference values established during calibration runs. When density deviations exceed a threshold, the system generates disturbance signals and switches to alternative calculation methods, thereby compensating for environmental interference and maintaining measurement reliability

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs beforehand cushioning by conducting calibration runs before normal operation to establish reference density values and detection thresholds. This preparatory step creates a buffer that allows the system to detect and correct for environmental disturbances during operation, preventing measurement errors rather than merely reacting to them

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Device complexity

If bulk material density is assumed constant for long-term measurement, then measurement simplicity is maintained, but reliable long-term measurement values cannot be obtained when density varies

Engineering Contradiction:
Improvemeasurement system complexityVSAvoidlong-term measurement reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent transitions from a static density assumption to a dynamic density determination approach. The system continuously calculates bulk material density from measured volume and weight data, allowing density to vary over time while maintaining measurement reliability. This dynamic adaptation enables accurate long-term measurements even when material properties change

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent performs preliminary calibration runs to establish baseline density values and detection thresholds before normal operation begins. This preliminary action creates reference data that enables the system to detect density variations during operation and switch to alternative measurement methods when needed, ensuring long-term reliability without excessive complexity

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4150304B1Method for determining the bulk density of bulk material in a mobile breaker
Publication Date: 2024.10.09 RUBBLE MASTER HMH GMBH
  • EP4150304B1 patent drawingFigure 1
  • EP4150304B1 patent drawingFigure 2

AI summary

The invention relates to a method for determining the bulk density of bulk material (2) in a mobile crusher, the bulk material volume of bulk material (2) delivered onto a conveyor belt (1) being determined. According to the invention, in order to configure a method of the above-described type such that the bulk material weight can be determined reliably over a relatively prolonged operating period of a mobile crusher, even with varying bulk material density, both the bulk material volume and the bulk material weight of a conveyor belt section (3) are sensed in successive time steps, and the bulk density is determined from the quotient of the bulk material weight and the bulk material volume.