Passive Acoustic Particle Size Analysis via Constant Flow Energy Control
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Solution Overview
Problem
Existing passive acoustic methods fail to provide representative measurement results for real-time grain size distribution analysis of granular materials across a wide range of grain sizes, from micrometers to decimeters, in various industrial conveying streams.
Innovation Solution
The method involves controlling the flow energy of the conveying stream to maintain constant speed and concentration of solid particles, allowing them to collide with an impact body, generating acoustic signals that are processed using a piezoelectric acceleration sensor to determine grain size distribution without requiring Fourier analysis transformations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If passive acoustic methods are used to measure grain size distribution in conveying streams, then real-time measurement capability is achieved, but measurement precision deteriorates because existing methods do not provide representative measurement results across a wide range of grain sizes
Solution Approach 1:
The patent changes the parameter of flow energy by controlling it to remain constant during measurement. This is achieved by regulating the conveying stream conditions so that particles impact the probe with consistent energy levels, enabling accurate grain size differentiation across a wide size range while maintaining real-time measurement capability
Solution Approach 2:
The patent uses a piezoelectric acceleration sensor that detects only the relevant portion of the impact signal - specifically the high-frequency components generated by particle collisions. By focusing on this partial signal rather than processing the entire acoustic spectrum, the system achieves precise grain size measurement while maintaining real-time operation
2Difficulty of detecting and measuring
If acoustic signals are processed using Fourier analysis transformations, then signal processing capability is enhanced, but device complexity increases
Solution Approach 1:
The patent replaces complex Fourier analysis transformations with a simpler signal processing approach based on piezoelectric sensor output interpretation. The system directly correlates sensor voltage signals with grain size parameters through calibrated relationships, eliminating the need for computationally intensive frequency domain transformations while maintaining measurement accuracy
Solution Approach 2:
The piezoelectric acceleration sensor inherently provides the necessary signal characteristics for grain size determination through its natural response to particle impacts. The sensor's electrical output directly reflects impact energy, which correlates with grain size, allowing the system to self-determine grain size distribution without requiring external complex processing systems
3Ease of operation
If the flow energy of the conveying stream is not controlled, then ease of operation is maintained, but reliability deteriorates because signal quality and reproducibility are insufficient
Solution Approach 1:
The patent implements flow energy control through a feedback mechanism that monitors conveying stream conditions and adjusts parameters to maintain constant impact energy on the probe. This feedback loop ensures that particles of different sizes impact with consistent energy levels, producing reproducible acoustic signals that reliably indicate grain size distribution
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 approach enables reliable, real-time grain size analysis across a wide grain spectrum in any type of flow, improving signal quality and reproducibility by ensuring constant flow energy and optimal sensor alignment for accurate acoustic signal detection.
Implementation Method 1
the electrical signals from the acceleration sensor are used for determining the grain size distribution
Implementation Method 2
granules... collide with at least one impact body set up as a waveguide and generate acoustic signals which appear in each impact body as structure-borne sound waves
Data Source
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AI summary
The invention relates to a passive acoustic method for continuously determining the particle size distribution of granular material in a delivery flow. Said granular material consists of solid particles of different particle sizes that are delivered in a delivery flow in a delivery device, collide with at least one impact element in the form of a waveguide and produce acoustic signals that propagate as solid-borne sound waves in each impact element. In order to devise a passive acoustic method for determining the particle size distribution of granular material which allows representative results when measuring the particle size distribution in real time, the flow energy of the delivery flow is controlled such as to maintain it constant and the solid particles in the delivery flow collide at a constant flow energy with the impact element of the measuring device. The specific control of the flow energy allows a particle size analysis of granular material in real time for a very broad particle size range of some micrometers up to several decimeters in any type of delivery flows, and on the basis of a passive acoustic method. The invention also relates to a device for carrying out the method.