Venturi Oxygen Regulator Pressure Measurement
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Solution Overview
Problem
Existing demand and dilution mask regulators for aircraft breathing apparatuses face challenges in accurately measuring oxygen flow rates due to turbulence in the mixing chamber, leading to a safety margin between required and supplied oxygen, which deviates from the minimum flow rate set by standards.
Innovation Solution
The use of a Venturi constriction to amplify and accurately measure the inhaled air flow rate, combined with a capillary duct for pressure measurement that does not disrupt airflow, allows for precise control of oxygen flow through electrically-controlled valves and an electronic circuit that calculates the required oxygen flow based on pressure and altitude data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is located near the mixing chamber to detect pressure drop, then the oxygen flow rate can be controlled, but turbulences in the mixing chamber disturb the pressure measurement reducing accuracy
Solution Approach 1:
The system is divided into separate measurement and mixing zones. The pressure sensor measures pressure in the dilution circuit away from the mixing chamber, while the Venturi constriction handles the mixing process. This segmentation isolates the sensitive pressure measurement from the turbulent mixing environment, eliminating measurement disturbances while maintaining flow control capability.
2Reliability
If a safety margin is maintained between required and supplied oxygen flow rates, then measurement inaccuracies are compensated, but the supplied oxygen deviates from the minimum standard flow rate
Solution Approach 1:
The system uses pressure sensors to continuously monitor pressure drops across the Venturi constriction and dilution circuit, feeding this information back to the electronic control circuit. The control circuit calculates the actual breath flow rate and adjusts the oxygen flow accordingly, eliminating the need for safety margins while ensuring precise compliance with minimum oxygen flow standards through continuous real-time feedback control.
Solution Approach 2:
The system replaces mechanical flow measurement methods with electronic pressure sensing and calculation. Instead of using complex mechanical flow meters that would be prone to turbulence interference, the system uses simple pressure sensors combined with electronic computation to accurately determine flow rates, achieving both reliability and precision.
3Measurement precision
If the Venturi constriction is used to amplify air flow rate measurement, then measurement accuracy improves, but the device complexity increases
Solution Approach 1:
The system employs a Venturi constriction, a well-established pneumatic device, to amplify and measure air flow rates. The Venturi effect creates a predictable pressure drop proportional to flow rate, which is easily measured by standard pressure sensors. This approach leverages proven pneumatic principles to achieve accurate flow measurement without requiring complex electronic sensors or sophisticated mechanical mechanisms.
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
This solution enables a more accurate and precise control of oxygen flow rates, bringing the supplied oxygen closer to the required flow rate, enhancing safety and compliance with standards by minimizing the safety margin and improving measurement accuracy.
Implementation Method 1
The Venturi constriction (41) amplifies the air inhaled breathe-in flow rate
Implementation Method 2
the pressure at the Venturi constriction is measured through the capillary duct
Data Source
AI summary
A demand and dilution mask regulator comprising an oxygen feed circuit and a dilution circuit for supplying air. The oxygen feed circuit and the dilution circuit are connected to a mixing chamber (35). In the dilution circuit, the inhaled breathe-in air flow rate is measured through a capillary duct (43) connected to a Venturi construction (41). A method of regulating the flow rate of additional oxygen uses flow rate data measured through the capillary duct (43) for controlling the oxygen flow rate to be supplied to the mixing chamber (35).