Airflow Measuring Device Throttle Wall Surface Dust Redirection
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Solution Overview
Problem
Conventional airflow measuring devices fail to effectively protect sensors from damage caused by nonideal collisions with dust of varying shapes, as their throttle wall surfaces are designed assuming ideal collisions, leading to ineffective dust reentrance prevention.
Innovation Solution
The airflow measuring device incorporates a throttle wall surface with a normal vector including a vector component in the width direction, and angles between the normal and reference vectors ranging from 90 degrees to 180 degrees, effectively redirecting and preventing dust reentrance regardless of collision type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the throttle wall surface is formed assuming ideal collision, then the design is simple, but dust reentrance is not effectively prevented
Solution Approach 1:
The patent changes the geometric parameters of the throttle wall surface by introducing a specific angle range (45° to 135° relative to the dust movement direction) and creating a specific region with modified surface orientation. This parameter modification enables the surface to effectively redirect dust particles of various shapes, transforming the design from ideal-collision assumption to a more robust configuration that handles nonideal collisions while maintaining manufacturing feasibility.
2Device complexity
If the throttle wall surface is designed for spherical dust particles, then the collision model is simplified, but protection against various dust shapes is insufficient
Solution Approach 1:
The patent introduces asymmetry in the throttle wall surface design by creating a specific region with a distinct angle range (45° to 135°) that differs from the rest of the surface. This asymmetric configuration is specifically tailored to handle non-spherical dust particles effectively, providing enhanced protection against various dust shapes while maintaining a relatively simple overall structure.
3Measurement precision
If the normal vector of the throttle wall surface is perpendicular to the reference vector, then ideal collision reflection is achieved, but nonideal collision dust is not effectively redirected
Solution Approach 1:
The patent extends the solution from a single-point collision model to a distributed angular approach by defining a specific region on the throttle wall surface where the normal vector angle relative to the reference vector falls within 45° to 135°. This dimensional expansion from a single optimal angle to a range of effective angles enables the surface to handle the three-dimensional complexity of nonideal collisions effectively.
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 configuration significantly reduces dust reentrance into the sensor area, reliably protecting the sensor from damage by aligning the throttle wall surface geometry to manage both ideal and nonideal collisions, ensuring high-precision detection signals even under pulsating air conditions.
Implementation Method 1
the sensor being configured to conduct heat transfer with air received in the case and to send an electric signal according to a flow amount of air in the duct
Implementation Method 2
the first passage has a throttle at a downstream of a branch position where the second passage is branched from the first passage, the first passage is configured to exhaust air into the duct while throttling air at the throttle
Data Source
AI summary
A first passage has a branch position where a second passage is branched from the first passage to move air along a reference vector. The second passage accommodates a thermal sensor. The first passage has a throttle at a downstream of the branch position. The throttle has a throttle wall surface having a normal vector directed inwardly. A width direction is perpendicular to both a flow direction of air in the throttle and the reference vector. The throttle wall surface has a specific region, in which the normal vector includes a vector component in the width direction, and an angle θ between the normal vector and the reference vector is in a range of 90 degrees<θ<180 degrees.