Thermal Flow Sensor Pin Sleeve Geometry for Direction Detection
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Solution Overview
Problem
Conventional thermal flow measuring devices struggle to accurately detect flow direction and sensor drift, as they rely on simplistic geometries that fail to distinguish between different flow directions and are prone to measurement errors due to heat transfer changes with temperature.
Innovation Solution
A thermal flow measuring device with a metal sensor housing featuring a unique geometry, including multiple pin sleeves with heaters and temperature sensors, and a flow obstruction, allowing for direction detection and drift determination by leveraging the power coefficients of the heaters and temperature sensors, while maintaining optimal heat transfer and minimizing eigenfrequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional thermal flow measuring devices use simplistic geometries with two pin sleeves, then the device structure is simple, but the device cannot accurately detect flow direction and is prone to sensor drift
Solution Approach 1:
The sensor housing is segmented into multiple functional pin sleeves (at least three pin sleeves) with different geometries and heater arrangements. Each pin sleeve serves a specific function: some for flow measurement and others for flow direction detection. This segmentation allows the device to perform multiple measurement functions simultaneously while maintaining a manageable structural complexity.
Solution Approach 2:
The invention transitions from a two-dimensional arrangement (two pin sleeves) to a three-dimensional arrangement with at least three pin sleeves positioned at different spatial locations and angles. The pin sleeves are arranged with specific angular separations (e.g., 120 degrees) and different lengths, creating a three-dimensional sensor configuration that enables flow direction detection through spatial analysis of temperature distributions.
2Adaptability or versatility
If the sensor housing geometry is optimized for multiple functionalities, then flow direction detection and drift determination are enabled, but the device complexity increases
Solution Approach 1:
The sensor housing is designed as a universal structure that performs multiple functions: flow rate measurement, flow direction detection, and sensor drift determination. The at least three pin sleeves with different geometries and heater configurations enable the same basic sensor structure to execute diverse measurement tasks, eliminating the need for separate devices for each function.
Solution Approach 2:
The invention merges flow measurement and flow direction detection capabilities into a single integrated sensor housing. The multiple pin sleeves with heaters are combined within one housing structure, allowing simultaneous execution of flow rate measurement and flow direction detection without requiring separate sensor assemblies.
3Measurement precision
If pin sleeves are arranged to separate heat input from flow measurement planes, then measurement accuracy improves, but manufacturing complexity increases
Solution Approach 1:
Different regions of the sensor housing are assigned different functional qualities: some pin sleeves have heaters positioned to create specific flow patterns, while others are positioned to measure temperature in undisturbed flow regions. The pin sleeves have different lengths and angular positions, creating local variations in heat input and measurement characteristics that optimize overall measurement accuracy.
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 precise flow direction detection and sensor drift compensation, ensuring accurate flow measurement and reducing measurement errors by utilizing a geometric arrangement that separates heat input from flow measurement planes and employs a monolithic, seam-free construction for stable and efficient heat transfer.
Implementation Method 1
In the first pin sleeve, especially in the terminal section of this pin sleeve, a first heater is arranged
Implementation Method 2
in the second pin sleeve, especially in the terminal section of this pin sleeve, a temperature sensor is arranged for ascertaining the temperature of the medium
Implementation Method 3
the flow obstruction can be, for example, a flat web or also a cylindrical or prismatically embodied pin sleeve. The terminology, flow shadow, means a shed wake region and/or a recirculation region
Data Source
AI summary
A thermal flow measuring device comprising a sensor with a metal sensor housing, the sensor housing including at least a first and a second pin sleeve extending from a base, each pin sleeve having a longitudinal axis and an end face, the two pin sleeves defining a connecting axis, wherein in the first pin sleeve a first heater is arranged and in the second pin sleeve a temperature sensor is arranged, wherein the sensor housing includes at least a third pin sleeve, having a second heater, and a flow obstruction embodied such that the third pin sleeve is arranged in a first flow direction at least partially in the flow shadow of the flow obstruction, wherein the first flow direction extends at an angle of 80-100° to the connecting axis and lies on a plane perpendicular to the longitudinal axes of the first and second pin sleeves.