Quartz Crystal Sensor Airborne Particle Sampling
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Solution Overview
Problem
Existing instruments for sampling and measuring airborne particulate matter are cumbersome and lack accuracy, particularly for regulatory compliance measurements, as they operate at high flow rates and struggle to differentiate and measure particles in the PM10, PM2.5, and PM1.0 size ranges effectively.
Innovation Solution
A compact apparatus with a particle separator and quartz crystal sensor system that removes coarse particles larger than 10 μm, charges and deposits smaller particles on a quartz crystal sensor, maintaining the chamber at a temperature to prevent vapor condensation, allowing for precise measurement of particle mass concentration in the PM10, PM2.5, and PM1.0 ranges with a significantly lower airflow rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing instruments operate at high flow rates to sample airborne particulate matter, then sampling speed is improved, but measurement precision and accuracy deteriorate
Solution Approach 1:
The sampling system is segmented into distinct functional modules: a particle separator that divides particles by size (PM10, PM2.5, PM1.0), a corona discharge charger that separates charging functions, and a quartz crystal microbalance that measures mass. This segmentation allows each component to operate optimally at lower flow rates while maintaining high sampling efficiency through the combined system.
Solution Approach 2:
The patent replaces traditional mechanical filtration and gravimetric measurement systems with a quartz crystal microbalance that uses piezoelectric effects to measure particle mass directly through frequency changes. This substitution enables precise measurements at lower flow rates, resolving the contradiction between sampling speed and measurement accuracy.
2Adaptability or versatility
If existing instruments are designed for comprehensive particle measurement, then measurement coverage is improved, but device complexity increases
Solution Approach 1:
The particle separator serves multiple functions: it separates PM10, PM2.5, and PM1.0 particles through a single device using staged impaction, eliminating the need for multiple separate sampling systems. The corona discharge charger simultaneously charges particles of different sizes, and the quartz crystal microbalance measures mass across all particle sizes, providing comprehensive measurement coverage with a unified compact apparatus.
Solution Approach 2:
The patent merges the particle separation, charging, and measurement functions into a single integrated system. The particle separator and corona charger are combined in one chamber, and the quartz crystal microbalance integrates mass measurement with the sampling flow path, creating a compact instrument that reduces complexity while maintaining comprehensive measurement capabilities.
3Measurement precision
If existing instruments are designed for high accuracy measurement, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The quartz crystal microbalance automatically measures particle mass by detecting frequency changes as particles deposit on the crystal surface, eliminating the need for manual filter handling and gravimetric calculations. The system self-calibrates and provides direct digital readings of particle mass concentration, making high-precision measurement accessible and easy to operate without specialized training.
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
The apparatus provides accurate and easy-to-use measurements with a reduced flow rate, enabling precise determination of particulate matter concentrations in ambient air, suitable for regulatory compliance and scientific research, while maintaining the precision needed for mass and chemical analysis.
Implementation Method 1
Charging the particles of less than about 10 μm in equivalent aerodynamic diameter with ions generated in a corona discharge
Implementation Method 2
A chamber containing a quartz crystal sensor permits the particles that have passed through to deposit to create an output signal in response to the deposited particle mass
Implementation Method 3
The chamber is maintained at a temperature sufficient to prevent vapor condensation on the sensor
Data Source
AI summary
An apparatus and method for sampling and measuring air born particulate matter includes an inlet for the particulate containing gas to enter. A mechanism then removes coarse particles larger than a selected size while permitting filtered particles of less than the selected size to pass through. A chamber containing a quartz crystal sensor permits the filtered particles that have passed through to deposit to create an output signal in response to the deposited particle mass.