Respiratory Device Measurement System Atmospheric Pressure Determination
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Solution Overview
Problem
Existing Positive Airway Pressure (PAP) devices face challenges in accurately determining the pressure, flow, and total volume of breathable gas delivered to patients, with existing sensors enhancing accuracy but increasing device cost.
Innovation Solution
A gas delivery system comprising a pressure generator, pressure sensor, control valve, and processor that measures pressure difference and flow rate to determine atmospheric pressure or density correction factor, allowing for precise control of breathable gas delivery without the need for additional costly sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional sensors (such as barometric pressure sensors) are added to enhance measurement accuracy, then the accuracy of determining pressure, flow, and total volume of breathable gas is improved, but the device cost increases
Solution Approach 1:
The existing pressure sensor in the PAP device is made to perform an additional function: determining atmospheric pressure and air density. By controlling the flow rate to substantially zero while the pressure generator operates, the pressure sensor measures the pressure difference between the pressurized breathable gas and atmospheric pressure, allowing the system to self-determine atmospheric conditions without requiring separate barometric sensors.
Solution Approach 2:
The pressure sensor is designed to serve multiple purposes: monitoring the pressure of pressurized breathable gas during normal operation and determining atmospheric pressure when flow rate is substantially zero. This multi-functionality eliminates the need for dedicated barometric pressure sensors, reducing device cost while maintaining measurement accuracy.
2Measurement precision
If additional sensors are added to improve measurement accuracy, then the accuracy of determining pressure, flow, and total volume is improved, but the device complexity increases
Solution Approach 1:
The pressure sensor and control valve work together to enable the system to self-determine atmospheric conditions. The processor controls the control valve to bring flow rate to substantially zero, at which point the pressure sensor's measurement of pressure difference allows the system to calculate atmospheric pressure and air density without external sensors.
Solution Approach 2:
The system changes the flow rate parameter to substantially zero to enable atmospheric pressure determination. By dynamically adjusting the flow rate through the control valve, the system creates conditions where the pressure sensor can accurately measure atmospheric pressure, allowing calculation of air density using ideal gas law relationships.
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 enhanced accuracy in measuring and controlling breathable gas delivery, reducing device complexity and cost while improving patient treatment efficacy.
Implementation Method 1
The pressure sensor measures a pressure difference between the pressurized breathable gas and atmospheric pressure
Data Source
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AI summary
A gas delivery system (12) comprising a pressure generator (14), a pressure sensor (21), a control valve (20), and a processor (32). The pressure generator (14) pressurizes breathable gas (22) for delivery to a patient. The pressure sensor (21) measures a pressure difference between the pressurized breathable gas (22) and atmospheric pressure. The control valve (20) is disposed downstream from the pressure generator (14) and is constructed and arranged to control a flow rate of the pressurized breathable gas (22). The processor (32) controls the control valve (20) to bring the flow rate of the pressurized breathable gas (22) to substantially zero while the pressure generator (14) is operating and, when the flow rate is substantially zero, determines at least one of atmospheric pressure, an atmospheric air density, or a density correction factor based at least in part on the pressure difference between the pressurized breathable gas (22) and the atmospheric pressure.