Ionic Wind Particle Sensor for Noiseless Airflow
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Solution Overview
Problem
Existing sensors for airborne particles larger than 10 nm face challenges in being noiseless, energy-efficient, and compact, with limitations in airflow generation and particle detection, especially in indoor environments where multiple measurement points are needed without significant environmental interference.
Innovation Solution
A sensor design utilizing a discharge electrode to generate unipolar ions creating an ionic wind for airflow, combined with a counter and screening electrode to charge and separate ions, and an electrostatic precipitation section for particle detection, along with an optional optical detection unit for larger particles, to provide efficient and low-resistance airflow and accurate particle measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a pump or ventilator is used to generate airflow through the sensor, then the airflow magnitude is determined by pump characteristics and pressure drop, but the device becomes more complex and energy-consuming
Solution Approach 1:
The sensor system generates its own airflow using the ionic wind produced by the discharge electrode and counter electrode combination. The ions generated between these electrodes create a self-sustaining airflow that moves particles through the sensing chamber without requiring external pumps or ventilators, making the system self-service for airflow generation
Solution Approach 2:
The patent replaces mechanical airflow generation systems (pumps, ventilators) with an electrostatic ionic wind system. The mechanical complexity of moving parts is substituted by an electric field-based ion generation mechanism that produces airflow through electrostatic forces acting on ions and neutral air molecules
2Speed
If thermal energy is supplied to induce airflow through thermal chimney effect, then airflow is generated, but energy consumption increases and vertical positioning is required
Solution Approach 1:
The patent replaces thermal energy-based airflow generation with an electrostatic ionic wind system. Instead of heating air to create convection currents, the system uses electric fields to generate ions that propel air molecules, eliminating the need for continuous thermal energy input and vertical positioning requirements
Solution Approach 2:
The patent changes the physical mechanism from thermal convection to electrostatic ion-driven flow. By altering the fundamental parameter from temperature gradient to electric field strength, the system achieves airflow generation without the limitations of thermal methods
3Adaptability or versatility
If multiple measurement points are deployed to monitor varying UFP concentrations in different rooms, then measurement coverage is improved, but cost per sensor needs to be low
Solution Approach 1:
The sensor's self-service airflow generation eliminates the need for external power-intensive components, reducing manufacturing complexity and cost. The ionic wind mechanism integrates airflow generation and particle detection in a single compact unit, making the sensor economical for widespread deployment across multiple measurement points
Solution Approach 2:
The sensor design integrates multiple functions (airflow generation, particle charging, and detection) into a single device that can be deployed universally across different environments. The compact, low-cost design allows the same sensor type to be used in various rooms and settings to monitor varying UFP concentrations
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 solution enables a noiseless, energy-efficient, and compact sensor that effectively measures airborne particles larger than 10 nm with minimal airflow resistance, providing accurate concentration and size data, and complements detection of fine particles beyond the ultrafine range, enhancing air quality monitoring.
Implementation Method 1
a discharge electrode for generating airborne unipolar ions in the passage
Implementation Method 2
The geometry of the air-pervious counter electrode is adapted to cause a downstream net flow of airborne ions substantially in the downstream direction of the passage such that the motion of airborne ions from the discharge electrode towards the counter electrode generates an ionic wind that can create and sustain an airflow through the passage
Implementation Method 3
The air-pervious screening electrode is adapted to subject airborne ions to an electrostatic force in a second direction, distinct from the downstream direction, for separating airborne ions from the airflow
Implementation Method 4
a particle sensing section for sensing electrically charged airborne particles in the passage
Data Source
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AI summary
A particle sensor is disclosed capable of sensing airborne particles larger than about 10 nm in an airflow passing through a passage inside the sensor. The sensor comprises a high- voltage discharge electrode for generating airborne unipolar ions that charge the airborne particles in the airflow. The generated ions are furthermore used to set-up an ionic wind between the discharge electrode and a counter electrode inside the sensor. The ionic wind is the driving force for maintaining the airflow through the sensor and allows sensor operation to occur free of audible noise. The presence of charged particles in the airflow is measured by an electrical current meter in the particle sensing section which measures the particle-bound charge that precipitates per unit time on the surface of a precipitation electrode after all airborne ions have been removed from air by a separate screening electrode positioned upstream of the particle sensing section.