Spherical Thermal Flow Sensor for Direction-Independent Sensitivity
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Solution Overview
Problem
Existing wind speed measurement systems using thermal flow sensors face challenges with directional sensitivity variations, requiring multiple temperature-sensitive elements that can lead to inconsistent sensor performance.
Innovation Solution
A flow sensor element with a spherical base body and a temperature-sensitive film pattern covering its entire surface, which changes electrical resistance with temperature, ensuring consistent sensitivity regardless of wind direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple temperature-sensitive elements are dispersively stuck on the surface of a casing, then wind speed measurement is enabled, but sensor sensitivity varies depending on wind blowing direction
Solution Approach 1:
The patent applies a spherical base body shape to eliminate directional sensitivity variations. The spherical geometry ensures uniform heat dissipation characteristics in all directions, allowing the temperature-sensitive film pattern to respond consistently regardless of wind direction. This curved surface approach resolves the contradiction by providing both measurement precision and directional independence simultaneously.
Solution Approach 2:
The patent merges multiple discrete temperature-sensitive elements into a single integrated temperature-sensitive film pattern that covers the entire spherical surface. This consolidation eliminates the directional sensitivity issues associated with discrete element placement while maintaining comprehensive wind detection capability across all directions.
2Area of stationary object
If a large number of temperature-sensitive elements are disposed on the surface, then coverage is improved, but disposition causes variation in sensor sensitivity
Solution Approach 1:
The patent combines multiple discrete temperature-sensitive elements into a single continuous temperature-sensitive film pattern that uniformly covers the spherical surface. This merging approach maintains full surface coverage while eliminating the sensitivity variations that arise from discrete element placement, thereby achieving both comprehensive coverage and uniform sensitivity.
Solution Approach 2:
The temperature-sensitive film pattern is designed to provide homogeneous sensitivity distribution across the entire spherical surface. This uniformity ensures that all regions of the sensor respond consistently to wind-induced heat dissipation, eliminating the non-uniform sensitivity problems associated with discrete element arrangements.
3Ease of manufacture
If discrete temperature-sensitive elements are used, then manufacturing is simplified, but sensor becomes directional and less accurate
Solution Approach 1:
The patent employs a thin film temperature-sensitive pattern that can be conformally deposited on the spherical surface. This thin film approach maintains manufacturing simplicity while achieving the directional independence and measurement accuracy required, as the continuous film structure responds uniformly to heat dissipation from all directions.
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 solution provides a non-directional, uniformly sensitive flow sensor element that improves detection accuracy of wind speed and reduces size while maintaining high responsiveness and minimizing air flow disturbance.
Implementation Method 1
temperature-sensitive elements receiving a thermal influence from outside air by performing heat exchange with outside air due to heat conduction
Implementation Method 2
temperature-sensitive elements receiving a thermal influence from outside air by performing heat exchange with outside air due to heat conduction
Implementation Method 3
temperature-sensitive film pattern that changes in electrical resistance value due to a change in temperature
Data Source
AI summary
An object is to provide a flow sensor element is non-directional and has an excellent sensor sensitivity. A flow sensor element includes a base body having a spherical shape, and a temperature-sensitive film pattern that is disposed over the entirety of a surface of the base body, and changes in an electrical resistance value due to a change in temperature. It is preferable that the temperature-sensitive film pattern be formed by trimming a temperature-sensitive film that has been formed on the surface of the base body. In the flow sensor element, the temperature-sensitive film pattern can be disposed over the entirety of the surface of the base body having a spherical shape. This enables a constant sensor sensitivity to be obtained regardless of a direction of a fluid, and the accuracy of detection of a flow rate can be improved.