Ecoair valve with pneumatic solenoid to provide auto zero function for air velocity pressure sensor
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Solution Overview
Problem
Airflow sensors in air ducts exhibit offset readings, leading to inaccurate measurements, especially at lower airflows, and these offsets can change over time, causing errors even after initial calibration.
Innovation Solution
An airflow sensor assembly with a pressure redirection device and a controller that pneumatically couples high and low pressure pickup devices to determine and adjust for offset values, allowing for periodic recalibration and providing accurate airflow measurements by subtracting the offset from the sensor readings and applying a gain value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a pressure redirection device is used to pneumatically couple high and low pressure pickup devices, then automatic calibration is enabled, but the device complexity increases
Solution Approach 1:
The pressure redirection device acts as an intermediary component that selectively connects the pressure sensor to either the high pressure pickup or low pressure pickup based on the calibration phase. This mediator enables automatic calibration functionality by facilitating the necessary pressure path switching without requiring complex external calibration equipment or manual intervention.
Solution Approach 2:
The system uses pneumatic principles to redirect pressure signals through the pressure redirection device, which switches between connecting the sensor to high pressure or low pressure pickups. This pneumatic switching mechanism enables automatic calibration functionality while maintaining a relatively simple device structure compared to alternative approaches that would require mechanical or electronic signal routing systems.
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 ensures accurate airflow measurements by automatically calibrating the sensor offset, reducing errors and maintaining precise readings over time, even at lower airflow conditions.
Implementation Method 1
The pressure redirection device is pneumatically coupled to the high pressure pickup device and the low pressure pickup device
Data Source
AI summary
An airflow sensor assembly for an air duct is provided. The airflow sensor assembly includes the air duct having an interior wall and an exterior wall, a high pressure pickup device, a low pressure pickup device, a pressure redirection device, and a pressure sensor. The pressure redirection device is fluidly coupled to the high pressure pickup device and the low pressure pickup device and includes a low inlet, a high inlet, and a common outlet. The pressure sensor is selectively fluidly coupled to the high pressure pickup device and the low pressure pickup device and includes a first inlet and a second inlet. The second inlet is fluidly coupled to the common outlet of the pressure redirection device.