Thermal Flow Sensor Heat Transfer Preventing Wall
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Solution Overview
Problem
Conventional thermal type flow sensors face accuracy issues in detecting fluid flow velocity or rate when installed in postures other than horizontal due to convection occurring between the temperature sensor and the heated fluid, limiting their usage.
Innovation Solution
Incorporating a heat transfer preventing wall between the temperature sensor and the heating element, along with a rectifying means like an orifice to prevent heated fluid from contacting the sensor and interrupt radiant heat, allowing accurate temperature detection regardless of posture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the flow path is arranged in a vertical direction with the temperature sensor positioned upward and the heating element positioned downward, then the device can be installed in narrow spaces, but convection is generated causing the heated fluid to rise and contact the temperature sensor, lowering detection accuracy
Solution Approach 1:
A heat transfer preventing wall is introduced as an intermediary component between the heating element and the temperature sensor. This wall blocks the direct thermal path and prevents heated fluid from contacting the temperature sensor, thereby eliminating convection-induced measurement errors while allowing vertical installation configurations
Solution Approach 2:
The flow path is segmented into distinct zones by the heat transfer preventing wall, creating a heated zone downstream and a measurement zone upstream. This segmentation isolates the temperature measurement from thermal interference, enabling accurate flow detection in vertical installations
2Measurement precision
If a heat transfer preventing wall is disposed between the temperature sensor and the heating element to prevent convection, then detection accuracy is improved, but the device complexity increases
Solution Approach 1:
The heat transfer preventing wall is implemented as a thin film or baffle structure that provides effective thermal blocking with minimal material and structural complexity. This thin-walled approach achieves the desired isolation while maintaining device simplicity and manufacturability
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
Enables reliable and accurate detection of fluid flow velocity or rate across various postures without size increase, enhancing detection accuracy by preventing convection and turbulence, and allowing flexible installation orientations.
Implementation Method 1
convection is generated accompanying rising of the fluid inside the flow path
Implementation Method 2
the fluid, which is heated at the downward location and undergoes a rise in temperature
Implementation Method 3
radiant heat from the heating element is interrupted
Data Source
AI summary
A measurement flow path is formed in a detector that makes up a thermal type flow sensor. A temperature sensor is disposed on an upstream side, and a heater is disposed on a downstream side in a fluid flow direction of the measurement flow path. Furthermore, a heat transfer preventing wall is disposed between the temperature sensor and the heater. Preferably, a rectifying means such as an orifice or the like is disposed on the downstream side of the heat transfer preventing wall, and between the temperature sensor and the heater.