Flow Rate Detection Unit Noise Reduction via Accelerating Flow Path
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional thermal flowmeters experience instability in gas flow and noise performance due to the division of gas flow at the end of the flow path exposing unit, leading to suboptimal detection performance.
Innovation Solution
A physical quantity detection device with a plate-shaped chip package that protrudes from the flow path wall, featuring an accelerating flow path with a narrower cross-sectional area than the main flow path, a measurement surface, a non-measurement surface, and a separation flow portion to stabilize gas flow and improve noise performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the flow path exposing unit is used to detect flow rate, then the flow rate can be measured, but the gas flow becomes unstable and noise performance deteriorates due to flow division at the end of the flow path exposing unit
Solution Approach 1:
The invention divides the flow path exposing unit into multiple independent detection regions (first, second, third, and fourth flow rate detection units arranged in a matrix). Each region independently measures flow rate, and the results are averaged to obtain the overall flow rate. This segmentation eliminates the flow division problem at the end of a single flow path while maintaining accurate flow rate measurement capability.
2Measurement precision
If the flow path cross-sectional area is reduced to increase flow velocity, then detection sensitivity improves, but flow instability increases
Solution Approach 1:
The invention transitions from a single linear flow path to a two-dimensional matrix arrangement of multiple flow rate detection units. This dimensional change allows the system to maintain narrow cross-sectional areas for high flow velocity and sensitivity in each unit, while the overall matrix structure provides flow stability through multiple parallel measurement paths.
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 device stabilizes gas flow through the accelerating flow path and enhances noise performance of the flow rate detection unit, improving measurement accuracy and reliability.
Implementation Method 1
a flow rate detection unit that detects a flow rate of the measurement target gas
Data Source
AI summary
Provided is a physical quantity detection device capable of improving noise performance of a flow rate detection unit as compared with the related art. The physical quantity detection device 20 includes a plate-like chip package 208 that is arranged to protrude from the flow path of the measurement target gas and has a width W along the flow direction of the measurement target gas. The chip package 208 includes a flow rate detection unit 205, an accelerating flow path 208c, a measurement surface 208a, a non-measurement surface 208b, and a separation flow portion 208d. The cross sectional area of the accelerating flow path 208c is reduced, and the flow rate detection unit 205 is arranged. The separation flow portion 208d partitions the second sub-passage 234b into a measurement flow path facing the measurement surface 208a and a non-measurement flow path facing the non-measurement surface 208b. In the width direction Dw of the chip package 208, the end portion 208ce of the accelerating flow path 208c and the end portion 208de of the separation flow portion 208d are separated from each other.