Particle Detector Flow Control via Segmented Fluid Paths
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Solution Overview
Problem
In particle detecting devices, maintaining a constant flow rate of fluid is crucial for accurate detection, but existing technologies face challenges in controlling and maintaining this flow rate, especially when detecting particles in fluids other than gases.
Innovation Solution
A particle detecting device with a chamber, introduction and discharge flow paths, flow meters, and a control unit that adjusts the total flow rate by combining the flow rates from the introduction and discharge paths to maintain a predetermined flow rate, using a suction unit and valve to regulate the flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a particle detecting device uses a simple flow path design, then device complexity is reduced, but flow rate control precision deteriorates
Solution Approach 1:
The flow path is divided into a particle-containing fluid introduction flow path and a particle-free fluid introduction flow path. This segmentation allows the particle-free path to serve as a dedicated reference for flow rate measurement without particle interference, while the particle-containing path maintains detection functionality. The division resolves the contradiction by creating specialized sub-systems that collectively achieve precise flow control without requiring complex overall design.
Solution Approach 2:
A particle-free fluid is introduced as an intermediary substance to establish a reference flow rate baseline. By comparing the particle-containing fluid flow against this particle-free reference, the system achieves precise flow rate control without requiring complex measurement mechanisms in the particle-laden path. The intermediary particle-free fluid acts as a mediator that enables accurate flow measurement indirectly.
2Ease of operation
If the flow rate of fluid is not kept constant, then ease of operation is improved, but detection accuracy deteriorates
Solution Approach 1:
The system employs feedback control by continuously measuring the flow rate of particle-free fluid through a flow meter and using this information to regulate the total flow rate. The control unit adjusts the flow based on the measured values, creating a closed-loop system that maintains constant flow rate automatically. This feedback mechanism resolves the contradiction by making flow rate control automatic and precise without requiring manual adjustment, thus maintaining both ease of operation and detection accuracy.
Solution Approach 2:
The particle-free fluid introduction system serves itself as a reference standard for flow rate measurement. By using the measured flow rate of particle-free fluid as the basis for calculating and controlling the total flow rate, the system performs self-regulation without external intervention. This self-service approach maintains constant flow rate automatically, ensuring detection accuracy while requiring minimal operational input.
3Measurement precision
If a flow meter is installed in the particle-containing fluid path, then flow rate measurement precision is improved, but the device complexity increases due to particle interference
Solution Approach 1:
The flow rate measurement function is extracted from the particle-containing fluid path and relocated to the particle-free fluid introduction path. By placing the flow meter in the particle-free path, the system eliminates particle interference with the measurement device while still obtaining the necessary flow rate data. This extraction resolves the contradiction by separating the measurement function from the particle-laden environment.
Solution Approach 2:
The system creates a copy of the fluid flow system using particle-free fluid that replicates the flow conditions without the harmful particles. This particle-free copy serves as a surrogate for measurement purposes, allowing accurate flow rate measurement to be performed on the copy rather than the original particle-containing fluid. The copying principle enables precise measurement without exposing the flow meter to particle damage or interference.
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 solution allows for easy maintenance of a constant flow rate, enhancing the accuracy of particle detection in fluids, including gases and liquids, by compensating for variations in flow rates, thereby improving the reliability of particle detection.
Implementation Method 1
If the gas contains microbial particles or non-microbial fluorescent particles, the particles illuminated by the excitation light emit fluorescence. This allows detection of the numbers and sizes of microbial particles and non-microbial fluorescent particles contained in the gas
Data Source
AI summary
A particle detecting device includes a chamber 30; a first introduction flow path 225 for introducing a particle-containing fluid into the chamber 30; a second introduction flow path 235 for introducing a particle-free fluid into the chamber 30; a light source 10 configured to illuminate fluid in the chamber 30 to detect particles contained in the fluid; a discharge flow path 260 for discharging fluid from the chamber 30; an introduction flow meter 245 configured to measure a flow rate of fluid flowing through the second introduction flow path 235; and a control unit 301 configured to perform control such that a fluid having a total flow rate obtained by adding a predetermined flow rate of fluid flowing through the first introduction flow path 225 to a flow rate of fluid flowing through the second introduction flow path 235, the flow rate being measured by the introduction flow meter 245, flows through the discharge flow path 260.