Electrostatic Ion Wind Flow Sensor for Particle Monitoring
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Solution Overview
Problem
Existing fine particle monitoring apparatuses face challenges in maintaining reliable and efficient air flow generation with low energy consumption, particularly in environments with changing operational parameters, and are sensitive to disturbances and particle accumulation, which affects the accuracy of particle concentration measurements.
Innovation Solution
The method involves generating airborne unipolar ions using a discharge electrode and a counter electrode to create a net airflow, modulating the corona voltage/current and ion trap voltage to determine the volumetric flow based on the time response of the electrical charge concentration, and using a secondary passage for particle removal to prevent corona needle soiling and maintain a stable ion wind.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional flow generation methods (fans, pumps, compressed gas) are used, then sufficient air flow can be generated, but maintenance requirements increase and reliability decreases
Solution Approach 1:
The patent replaces mechanical flow generation systems (fans, pumps) with an electrostatic field-based ion wind system. A discharge electrode generates ions that are attracted to a counter electrode, creating a body force that drives air flow without moving parts, thereby eliminating mechanical maintenance and improving reliability
Solution Approach 2:
The patent employs periodic switching of the discharge electrode between different operational states (on/off or different voltage levels) to create time-dependent air flow patterns. This periodic action allows control of flow characteristics while maintaining the simplicity and reliability of the electrostatic system
2Measurement precision
If clean air is supplied continuously to maintain measurement accuracy, then measurement precision is improved, but energy consumption increases
Solution Approach 1:
The patent uses feedback control by continuously monitoring the air flow rate and adjusting the discharge electrode operation accordingly. The system determines actual flow rate based on ion generation characteristics and uses this information to modulate the discharge electrode, maintaining measurement accuracy while optimizing energy consumption
Solution Approach 2:
The patent implements dynamic control of the discharge electrode switching frequency and voltage based on real-time flow conditions. This dynamic adjustment allows the system to adapt to changing operational parameters and maintain measurement precision without continuous high energy input
3Stability of the object's composition
If the discharge electrode operates continuously to maintain stable ion wind, then air flow stability is improved, but particle accumulation on the electrode increases
Solution Approach 1:
The patent applies periodic switching of the discharge electrode between active ion generation and idle states. This periodic operation reduces continuous particle accumulation on the electrode surface while maintaining sufficient ion wind stability for measurement purposes by controlling the duty cycle and timing
Solution Approach 2:
The patent implements a recovery phase in the periodic cycle where the discharge electrode is deactivated or operated at reduced voltage, allowing particles to be cleared from the electrode surface before the next active phase, thereby maintaining electrode cleanliness and ion wind stability
4Productivity
If the air flow rate is increased to improve measurement speed, then productivity is improved, but measurement precision decreases due to disturbed flow
Solution Approach 1:
The patent uses dynamic modulation of the discharge electrode switching frequency to control air flow rate. By adjusting the switching parameters, the system can optimize the balance between flow rate (productivity) and flow stability (measurement precision), adapting to different measurement requirements
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 accurate and continuous determination of volumetric flow with low energy consumption, reducing maintenance needs and maintaining measurement accuracy even under changing conditions, while minimizing errors and maintaining a stable air flow for particle concentration monitoring.
Implementation Method 1
generating airborne unipolar ions with a discharge electrode
Implementation Method 2
create a net flow of airborne ions and thereby generating an airflow
Implementation Method 3
a counter electrode adapted to attract said airborne ions to cause a net flow of airborne ions
Implementation Method 4
determining the volumetric flow on the basis of the time response which switching or modulation creates to the concentration of airborne electric charge
Data Source
AI summary
Apparatus (1) for generating acknowledged flow (Q), comprising a first passage (2) with ends (3,4) for acknowledged flow (Q) inlet and outlet, a discharge electrode (5) for generating airborne unipolar ions (8) positioned inside the first passage (2), a counter electrode (6) adapted to attract said airborne ions (8), thereby being adapted to cause a net flow (7) of airborne ions (8) and thereby generating an airflow (Q) in the direction of the net flow of airborne ions (8), sensing element (12, 13), the output of which is a function of the concentration of the airborne electric charge (8, 11), means (17) for switching or modulating a parameter which affects the output of the sensing element (12,13) and means for determining the volumetric flow (Q) on the basis of the time response which switching or modulation creates to the sensing element (12,13) output. 11. Use of apparatus (1) as described in the previous claims for determining ultrafine particle concentration. Process for generating acknowledged flow.