Airflow measuring system for a building having a sensor assembly mounted to a wall of an air conduit
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Solution Overview
Problem
Existing airflow measuring devices in buildings face accuracy limitations due to placement challenges near obstructions like dampers and louvers, impacting comfort and energy costs.
Innovation Solution
A U-shaped sensor assembly with extruded venturi legs and corner members, featuring a sensor housing and airflow sensor, is mounted in an air conduit to accurately measure airflow with minimal resistance and pressure drop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional airflow measuring devices are placed near obstructions like dampers and louvers, then placement flexibility is improved, but measurement accuracy deteriorates
Solution Approach 1:
The device is divided into multiple sections (first section with first and second chambers, second section with third and fourth chambers, third section with fifth and sixth chambers) connected by corner members and conduits. This segmentation allows the device to be placed in various positions within the air conduit while maintaining accurate airflow measurement through distributed pressure sensing chambers.
Solution Approach 2:
Multiple pressure ports and chambers are introduced as intermediary elements between the airflow and the measurement mechanism. These chambers (first through sixth chambers) with pressure ports capture pressure information at different locations, and the processor integrates these intermediate measurements to calculate accurate airflow values even when placed near obstructions.
2Measurement precision
If a complex sensor assembly is used to improve measurement accuracy, then airflow measurement precision is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The sensor assembly is designed as a universal device that can be placed in various positions within air conduits (upstream, downstream, near obstructions) and still provide accurate measurements. The multiple chambers and pressure ports serve multiple functions: pressure sensing, flow direction detection, and compensation for placement variations, reducing the need for multiple specialized devices.
Solution Approach 2:
The device utilizes changes in pressure parameters across multiple chambers and ports to determine airflow characteristics. The processor analyzes pressure differentials between various chambers (first-second, third-fourth, fifth-sixth chambers) to calculate airflow rate and direction, transforming complex physical flow patterns into measurable pressure parameter changes.
3Measurement precision
If a complex sensor assembly is used to improve measurement accuracy, then airflow measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The device is divided into modular sections (first section, second section, third section) that can be manufactured separately and assembled using corner members and conduits. This segmentation enables standardized manufacturing processes for each module, reducing overall manufacturing complexity and cost while maintaining measurement accuracy through the distributed chamber design.
Solution Approach 2:
The design uses repeated patterns of chambers and pressure ports across multiple sections (first through sixth chambers in three sections). This copying of functional units allows for efficient manufacturing through repetition of standardized components, reducing tooling costs and assembly complexity while providing redundant measurement capabilities for improved 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
The system provides accurate mass airflow measurement with reduced manufacturing costs and minimal disruption to airflow, enhancing comfort and optimizing HVAC system performance.
Implementation Method 1
a first pressure port in communication with the first chamber and a second pressure port in communication with the second chamber
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A mass airflow measuring system includes an air conduit and a sensor assembly including a first section (31) with inlet and outlet chambers and a wall separating the inlet and outlet chambers. A second section (32) has a third inlet chamber and fourth outlet chamber and a wall separating the third and fourth chambers. A third section (33) has a fifth chamber and a sixth chamber separated by a wall. The third section forms a conduit between said first and second sections. A first corner member (34) connects the first section to the third section and a second corner member (34) connects the second section to the third section to form a u-shaped assembly. Alternatively, L-shaped and horizontal configurations are also provided.