Triboelectric Particle Sensor AC Signal Decoupling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing particle concentration sensors struggle to accurately measure particle concentration in fluid flows with variable flow velocities, as they are significantly affected by variations in particle velocity and require complex calibration procedures or expensive ultra-wide band electronic circuitry.
Innovation Solution
The method involves disposing a probe into the fluid flow to charge it electrically, measuring the induced electric signal, determining the magnitude of the AC component of the signal across its full bandwidth (5Hz to 50Hz), and calculating the particle concentration by correlating the AC component magnitude with the flow velocity, which is determined by the average frequency of the AC component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the DC component of the induced signal is evaluated to determine solid particle concentration, then the measurement is simple, but the measurement fails to accurately measure solid particle concentration in the presence of variable flow velocity
Solution Approach 1:
The patent changes the evaluation parameter from DC component to AC component of the induced signal. By evaluating the AC component (alternating current component) instead of the DC component, the system can accurately measure particle concentration while compensating for flow velocity variations through mathematical processing that separates concentration signal from velocity interference.
Solution Approach 2:
The patent incorporates flow velocity information as feedback to compensate for its interfering effect on the concentration measurement. By detecting flow velocity (through means such as hot wire anemometry or laser doppler velocimetry) and using this feedback to mathematically adjust the AC signal evaluation, the system eliminates the error caused by variable flow velocities.
2Measurement precision
If cross correlation is used to measure flow velocity with two triboelectric probes, then flow velocity can be measured, but the system cost and complexity increase significantly
Solution Approach 1:
The patent segments the measurement function by separating flow velocity measurement from particle concentration measurement. Instead of using two probes for both functions, it uses one triboelectric probe for concentration and a separate (simpler) velocity measurement system, dividing the complex task into two independent but coordinated measurements.
Solution Approach 2:
The patent introduces an intermediary mathematical processing stage that receives both the AC signal from the triboelectric probe and the flow velocity data, then combines them through mathematical operations (such as dividing the AC signal by the velocity measurement) to produce the final concentration result, thereby eliminating the need for a second triboelectric probe.
3Measurement precision
If mathematical compensation for flow velocity is performed without an additional probe, then particle concentration can be measured accurately, but the calibration procedures become complex and computationally intensive
Solution Approach 1:
The patent enables the single triboelectric probe system to self-compensate for flow velocity effects by mathematically processing the AC signal component in conjunction with velocity data. The system uses the AC signal's inherent characteristics (which contain velocity information) and combines it with external velocity measurements to automatically calculate concentration, eliminating the need for complex external calibration procedures.
4Measurement precision
If ultra-wide band electronic circuitry is used to distinguish individual particle interactions, then particle concentration can be measured, but the system becomes expensive and prone to electro-magnetic compatibility issues
Solution Approach 1:
The patent extracts the essential measurement function from the complex ultra-wide band circuitry by focusing on the AC component of the signal, which contains the necessary concentration information. By taking out only the AC component evaluation (rather than requiring full ultra-wide band processing), the system achieves accurate measurement with simpler, more cost-effective electronic circuits that are less susceptible to EMC issues.
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 accurate measurement of particle concentration in fluid flows with variable flow velocities, improving measurement reliability and reducing system complexity and cost, by effectively decoupling particle concentration from flow velocity variations.
Implementation Method 1
The probe is charged triboelectrically by the particles in the gas flow and the signal generated in the circuit is evaluated to give an output providing an indication of the particle flow.
Implementation Method 2
The alternating current (AC) component of the signal is evaluated in a frequency band between 0.1Hz and 2Hz.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method (200) of and a particle concentration sensor (100) for measuring particle (103) concentration in a fluid flow. The method comprises the steps of disposing (201) a probe in the flow, such that the probe is charged by particles in the flow; measuring (203) an electric signal induced by the charging of the probe; determining (209) the magnitude of an AC component of the signal; determining (211) the flow velocity; and calculating (213), from the magnitude of the AC component and the flow velocity, the particle concentration in the flow.