Venturi air flow sensor and control system
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Solution Overview
Problem
Existing air flow sensors in air duct systems, including those using Venturi housings, face inaccuracies in air flow determination due to clogging from lint and other airborne particulate matter, and fail to account for pressure variations across the diameter, resulting in low accuracy, typically no better than 5%.
Innovation Solution
A Venturi air flow sensor and control system with high and low pressure sensor tubes extending across the diameter of the Venturi housing, each with multiple downstream-facing openings, providing an average pressure reading and avoiding clogging by facing away from the air flow direction, thus improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If upstream openings are used for high pressure sensing, then air flow measurement is enabled, but clogging from lint and airborne particulate matter occurs
Solution Approach 1:
The patent inverts the conventional approach by using downstream-facing openings instead of upstream-facing openings for pressure sensing. This reversal prevents lint and particulate matter from entering the sensor tubes while still enabling accurate pressure differential measurement for air flow calculation.
Solution Approach 2:
The patent introduces an intermediary mechanism where the sensor tubes extend across the entire diameter of the duct and utilize the Venturi effect created by the housing geometry. This intermediary structure allows indirect pressure sensing that avoids direct exposure to clogging particles while maintaining measurement capability.
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 achieves significantly improved air flow determination accuracy, exceeding 2.75%, while preventing clogging from airborne particulate matter, by using sensor tubes that extend across the diameter and face downstream, providing a more reliable measurement.
Implementation Method 1
The Venturi air flow sensor typically has a high pressure section with a diameter that is sized compatibly with the system air ducts and a low pressure center section resulting from a reduced diameter of the Venturi housing
Implementation Method 2
The differential pressure between the high pressure tube and the low pressure tube is then used to calculate the air flow through the Venturi
Data Source
AI summary
A Venturi air flow sensor and control system includes a Venturi housing comprising with an inlet section, an outlet section, and a reduced diameter horn shaped center section connecting the inlet section to the outlet section with a damper. A high pressure sensor tube with downstream openings extends across the inlet section on the outlet section and a low pressure sensor tube with downstream openings extends across the reduced diameter horn shaped section. The pressure from the low pressure sensor tube and the pressure from the high pressure sensor tube are connected to a controller. From the high pressure and the low pressure the controller determines the air flow and based on air flow operates the damper.