Optical Aerosol Particle Analysis With Upstream Centrifugal Separation
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Solution Overview
Problem
Existing aerosol measurement technologies can only determine the optical size of particles based on scattered light signals, which is insufficient for distinguishing between particles with different refractive indices, forms, and densities, leading to inaccuracies in size determination.
Innovation Solution
A method and device that utilize a separator upstream of the optical sensor unit to separate particles based on size and/or mass, using a centrifugal separator to apply centrifugal force, allowing for the determination of aerodynamic diameters and improved separation of fine dust fractions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If optical measurement is used to determine particle size, then measurement speed is improved, but measurement precision deteriorates because particles with different refractive indices, forms, and densities cannot be distinguished
Solution Approach 1:
The measurement process is segmented into multiple channels (up to 256 channels) that record scattering signals at different angles or wavelengths. This segmentation allows the system to capture multiple characteristics of each particle simultaneously, enabling differentiation between particles with different optical properties while maintaining high measurement speed through parallel processing
Solution Approach 2:
The invention transitions from single-dimensional optical size measurement to multi-dimensional characterization by recording scattering signals across multiple channels. This adds dimensions of measurement (different scattering angles, wavelengths, or temporal characteristics) that provide additional information about particle refractive index, form factor, and density, thereby improving measurement precision without sacrificing speed
2Measurement precision
If a separator is added to the device for size- and/or mass-sensitive separation, then particle separation efficiency is improved, but device complexity increases
Solution Approach 1:
The separator is integrated within the existing aerosol measurement device structure, with the aerosol flow path passing through the separator before reaching the optical measurement channels. This nesting approach allows the separator to be incorporated without requiring a completely separate system, thereby improving particle separation efficiency while minimizing the increase in overall device complexity
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 accurate determination of fine dust fractions by separating particles according to size and mass, overcoming inaccuracies in optical measurement by determining aerodynamic diameters and improving separation efficiency.
Implementation Method 1
individual particles are counted on the basis of a signal generated by light scattering on them
Implementation Method 2
a separator for size- and/or mass-sensitive separation of particles is arranged upstream of the sensor unit
Data Source
AI summary
In order to achieve improved determination of fine dust particles, a method is provided for determining particles of an aerosol whereby, in a first measuring step, aerosol is fed to an optical aerosol measuring device without being influenced by a controllable centrifugal separator, at least in a further measuring step aerosol is guided to the optical measuring device while being influenced by the centrifugal separator rotating at least at a speed deviating from the speed 0, and properties of the particles of the aerosol are determined from the received measurement signals of the optical measuring device in the first and in at least one further measuring step. A device is also provided, which has an optical sensor unit forming the measuring volume for recording particles, and is designed such that a separator for size- and/or mass-sensitive separation of particles is arranged upstream of the sensor unit.