Thermal Flow Sensor Sub-Passages for Thin Profile and Contaminant Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Thermal type flow measuring devices face challenges in achieving a thin shape with accurate flow measurement while protecting the sensor element from contaminants, as existing designs often result in increased thickness due to the placement of the sensor element and curved passages that fail to effectively divert soil substances and dust.
Innovation Solution
The device incorporates a sub passage configuration with a first and second sub passage portion forming layers on either side of a separation wall, a linear third sub passage portion extending across both sides, and communication passages that allow directional changes, enabling the sensor element to be positioned in a linear passage for improved protection and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor element is disposed in a curved sub passage to protect it from contaminants, then the protection against soil substances and dust is improved, but the thickness dimension of the device increases due to the curved passage configuration
Solution Approach 1:
The patent transitions from a planar curved passage configuration to a three-dimensional folded passage structure. The sub passage is configured to fold back on itself within the same plane, creating multiple directional changes without requiring additional thickness. This allows the sensor element to be positioned in a region protected from direct contaminant exposure while maintaining a compact thin-profile device geometry.
2Measurement precision
If the sub passage is configured with multiple directional changes to divert contaminants, then the flow measurement accuracy is improved, but the device complexity increases
Solution Approach 1:
The sub passage is segmented into distinct sections: an inlet section, a measurement section where the sensor element is disposed, and an outlet section. Each section serves a specific function, with the measurement section positioned to receive cleaned fluid after contaminants have been diverted in the inlet section. This segmentation allows for effective flow measurement while maintaining a relatively simple overall passage structure.
Solution Approach 2:
The patent employs curved passage sections to smoothly redirect fluid flow and contaminants. The curved geometry naturally directs heavier contaminants away from the measurement region through centrifugal effects, improving measurement accuracy without requiring sharp angles or complex mechanical components that would increase device complexity.
3Reliability
If the sub passage forms a loop of 360 degrees to protect the sensor element, then the protection against incoming water drops and soil substances is improved, but the thickness dimension increases when inlet and outlet openings are on perpendicular planes
Solution Approach 1:
The patent employs an asymmetric passage configuration where the sub passage does not form a complete symmetric 360-degree loop. Instead, the passage is designed with asymmetric folding that achieves contaminant diversion and sensor protection within a smaller angular range. The inlet and outlet openings are positioned asymmetrically to optimize both protection and compactness, avoiding the need for a full perpendicular loop configuration.
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 reduces the thickness of the device while effectively diverting contaminants away from the sensor element, enhancing flow measurement accuracy and protection against contamination.
Implementation Method 1
In the curved first section, soil substances (liquid droplet, oil droplet) which soil the sensor element, and dust and the like (solid particles) which has a high risk of breaking the sensor element are pushed away to a region on the outer side (outer peripheral side) of the first section by an inertial force (centrifugal force).
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A first sub passage portion and a second sub passage portion are configured so as to form layers on both sides of a separation wall, respectively. A linear passage portion of a third sub passage portion is formed so that a cross section thereof extends within a range across both sides of the separation wall in a direction perpendicular to a wall surface of the separation wall. The cross section is taken along a direction perpendicular to a flow direction of a fluid flowing through the linear passage portion. The separation wall separates the layer of the first sub passage portion and the layer of the second sub passage portion from each other. A first communication passage portion which allows the first sub passage portion to communicate with the third sub passage portion curves to make a directional change and connects a passage wall surface of the first sub passage portion to a side wall of the third sub passage portion by an inclined surface. The passage wall surface is defined by the separation wall. The side wall is located on a side of the second sub passage portion with respect to the separation wall. A through passage which passes through the separation wall is provided in a second communication passage portion which allows the second sub passage portion to communicate with the third sub passage portion.