Particle Sensor Recirculation Loop for Detection Range
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Solution Overview
Problem
Current particle sensors struggle to detect low concentrations of particles in a practical timeframe and often saturate at higher concentrations, limiting their detection range and accuracy, especially for PM2.5 particles which are harmful and require precise monitoring.
Innovation Solution
A particle sensing apparatus with a recirculation loop and a force applicator that directs particles either into the recirculation loop for increased detection sensitivity or towards the outlet to prevent saturation, using readily available and low-cost components like heat, electromagnetic radiation, or sound to control particle flow, allowing for adjustable force application based on concentration thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If particles are recirculated through the sensor to increase detection sensitivity for low concentrations, then the detection limit is improved, but the sensor may saturate when higher concentrations are present
Solution Approach 1:
The system dynamically adjusts particle recirculation based on real-time concentration measurements. When low concentrations are detected, particles are recirculated through the sensor multiple times to enhance detection sensitivity. When high concentrations are detected, recirculation is reduced or stopped to prevent sensor saturation, thus adapting the detection process to current conditions
Solution Approach 2:
The system uses feedback from particle concentration measurements to control the recirculation process. The sensor continuously monitors particle concentration and adjusts the recirculation rate accordingly, creating a closed-loop control system that optimizes detection for varying concentration levels
2Adaptability or versatility
If the sensor operates continuously without recirculation to handle high particle concentrations, then the detection range is maintained, but the time to reach stable readings at low concentrations increases significantly
Solution Approach 1:
The system dynamically switches between recirculation and non-recirculation modes based on detected particle concentration levels. For low concentrations, recirculation is activated to reduce stabilization time. For high concentrations, recirculation is deactivated to maintain accurate detection range, thus adapting operation mode to current conditions
3Measurement precision
If a force applicator is used to direct particles into the recirculation loop for low concentration detection, then the detection sensitivity is enhanced, but the device complexity increases
Solution Approach 1:
The patent replaces complex mechanical particle manipulation systems with a force applicator that uses non-mechanical forces (such as acoustic, optical, or electromagnetic forces) to direct particles into the recirculation loop. This substitution reduces mechanical complexity while maintaining particle control capability
Solution Approach 2:
The force applicator is designed to perform multiple functions: it can direct particles into recirculation for low concentration detection, and can also be used for other particle manipulation tasks within the sensor system, reducing the need for separate specialized 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 significantly enhances the detection limit and range of particle sensors, enabling faster and more accurate measurement of low-concentration particles while preventing sensor saturation at higher concentrations, thereby improving air quality monitoring efficiency.
Implementation Method 1
a force applicator to apply a force to the particles entrained in the fluid such that the particles move relative to said flow, the force applicator being arranged to control the passage of the particles into the recirculation loop or to the downstream outlet
Implementation Method 2
They are typically based on the measurement of light scattered at the particles which are entrained by an air flow through a detection volume
Implementation Method 3
an inlet particle sensor for detecting an inlet concentration of particles in the fluid
Data Source
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AI summary
A particle sensing apparatus is provided for determining particle concentration in a fluid, e.g. air. The apparatus is based on fluid-flow passageway having an upstream inlet to receive the fluid and a downstream outlet to exhaust the fluid. It also includes a recirculation passageway in fluid communication with the fluid-flow passageway. Between them, the fluid-flow passageway and the recirculation passageway define a recirculation loop. A first particle sensor is located in the recirculation loop, and other sensors may also be present at other options. A force applicator is included in the fluid-flow passageway to apply a force to the particles entrained in the fluid. The force is used to direct some or all of the particles into the recirculation loop. This provides a choice between increasing the detection limit or the detection range. A processor determines the concentration of particles in the fluid based on the concentration of particles detected at the first particle sensor.