Volatile Particle Detection via Heating and Dilution
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Solution Overview
Problem
Current methods for measuring suspended particles in waste gases are inefficient, particularly for small and volatile particles, as they either overcomplicate the measurement process or fail to accurately characterize particle noxiousness, and existing devices are large, expensive, and not suitable for compact applications like local traffic offices or garages.
Innovation Solution
A device and method that separates volatile suspended particles by heating the aerosol to evaporate volatile constituents and then diluting the aerosol with a particle-free carrier gas to reduce vapor pressure, ensuring only solid particles are measured, and a dilution unit that adjusts dilution based on waste gas volume flow to maintain accurate particle concentration measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional gravimetric methods are used to measure particle mass, then the measurement device is simple, but small and middle-sized particles are attributed low weight which does not reflect their actual noxiousness
Solution Approach 1:
The invention changes the measurement parameter from particle mass (gravimetric) to particle number concentration. This is achieved by using condensation nucleus counters that detect particles based on their ability to act as condensation nuclei, rather than measuring their mass. This parameter change allows small particles to be properly weighted according to their number, accurately reflecting their noxiousness while using relatively simple measurement principles.
Solution Approach 2:
The invention employs phase transitions (condensation and evaporation) as the core measurement mechanism. Condensation nucleus counters utilize the condensation of vapor onto particles to detect and count them. The phase transition approach enables detection of particle number rather than mass, providing accurate noxiousness characterization without complex gravimetric measurement systems.
2Measurement precision
If full flow dilution is used to measure particle concentration, then the concentration measurement is accurate, but the device becomes very large, complicated and expensive
Solution Approach 1:
The invention extracts only the essential function of dilution (reducing particle concentration to measurable levels) and implements it in a simplified manner. Instead of complex full flow dilution systems, the patent uses straightforward dilution techniques combined with sensitive particle counters. This extraction of the core dilution function eliminates unnecessary complexity while maintaining measurement accuracy.
Solution Approach 2:
The invention replaces complex mechanical dilution systems with alternative approaches. Rather than using large mechanical dilution devices, the patent employs electrical and optical measurement systems (condensation nucleus counters, light scattering instruments) that can accurately measure particle concentrations with minimal or no mechanical dilution, thereby reducing device complexity and size.
3Measurement precision
If volatile suspended particles are included in measurements, then the total particle mass is captured, but the measurement does not accurately reflect respiratory noxiousness since volatile particles are less harmful
Solution Approach 1:
The invention uses phase transitions (evaporation and condensation) to separate volatile from non-volatile particles. By heating the aerosol sample, volatile particles evaporate and can be distinguished from solid particles that remain. This phase transition-based separation allows measurements to focus on non-volatile particles that are more relevant to respiratory noxiousness, without requiring complex separation apparatus.
Solution Approach 2:
The invention changes the temperature parameter to differentiate between volatile and non-volatile particles. By controlling temperature and observing phase changes, the measurement system can selectively detect or exclude volatile particles. This parameter change approach provides a simple method to characterize respiratory noxiousness by focusing on persistent solid particles rather than transient volatile components.
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 allows for reliable, compact, and cost-effective measurement of solid particle concentration, reducing the impact of volatile particles and handling changing volume flows, providing more accurate characterization of aerosol noxiousness and particle number measurements.
Implementation Method 1
the volatile suspended particles are heated in a heating path in such a manner that the volatile suspended particles change over into the gas phase
Implementation Method 2
in a dilution unit arranged downstream, the heated aerosol is diluted with particle-free carrier gas
Data Source
AI summary
Volatile suspended particles are eliminated from an aerosol by heating the aerosol to a temperature at which the volatile suspended particles evaporate and diluting the aerosol with a dilution gas. The sequence heating and diluting may be performed in any order. According to another aspect of the invention, dilution of the raw gas takes place such that raw gas is led to a measurement gas channel through which measurement gas flows, wherein the quantity of raw gas transferred per unit of time is dependent on the volume flow in the raw gas channel. According to a further aspect of the invention, in a condensation nucleus counter the number and intensity of scattered light pulses evaluated in order to be able to draw conclusions on the reliability of the measurement.