Dual-Range Pitot Tube for Accurate Respiratory Flow Measurement
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Solution Overview
Problem
Existing fluid flow devices are optimized for specific flow rates and are not suitable for performing a range of respiratory tests, requiring multiple devices for accurate diagnosis and monitoring, which are costly and difficult to clean without damaging sensing equipment.
Innovation Solution
A device with a housing defining a flow channel, incorporating a first pitot tube with a port facing opposite to the flow direction for stagnation pressure measurement and a second port for static pressure measurement, using sensor assemblies sensitive to different pressure ranges to perform multiple respiratory tests, including spirometry and FeNO, with minimal pressure drop and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single Pitot tube design is used, then the device complexity is low, but the measurement precision deteriorates for different flow rates
Solution Approach 1:
The Pitot tube is divided into multiple sensing ports (first plurality and second plurality) positioned at different locations along the tube. Each port measures pressure at its specific position, allowing the system to capture pressure variations across different flow conditions. This segmentation enables accurate measurement across a broader range of respiratory flow rates without requiring multiple separate devices.
Solution Approach 2:
The patent implements dynamic selection of sensing ports based on the detected flow rate. The processor selectively uses different ports depending on whether the flow rate is high or low, optimizing measurement precision for each condition. This dynamic adaptation allows a single device to maintain high precision across varying respiratory conditions without increasing physical complexity.
2Measurement precision
If multiple Pitot tubes are used for different flow rates, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
Multiple sensing ports that would traditionally require separate Pitot tubes are merged into a single integrated tube structure. The first and second pluralities of sensing ports are positioned at different locations along one Pitot tube, combining the functionality of multiple devices into one unified structure, thereby maintaining measurement precision while reducing overall device complexity.
Solution Approach 2:
The single Pitot tube structure serves multiple functions by incorporating sensing ports that can measure pressure for both high and low flow rates. The processor selectively activates appropriate ports based on flow conditions, making the device universal for measuring various respiratory flow rates without requiring separate specialized tubes for each condition.
3Ease of operation
If the Pitot tube is positioned away from the patient interface, then the ease of operation improves, but the measurement precision deteriorates due to transducer isolation
Solution Approach 1:
The patent transitions from direct mechanical coupling to spatial separation with signal transmission. By positioning the transducer in a different location and using fluid-filled tubing to transmit pressure signals, the system achieves both ease of operation (flexible positioning) and measurement precision (maintained signal integrity) by operating in a different dimensional arrangement.
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 device accurately measures a wide range of flow rates, reducing the need for multiple devices and enabling thorough respiratory diagnosis and monitoring, while being cleanable without damaging sensors.
Implementation Method 1
Pitot tubes are traditionally used to measure fluid flow rates
Data Source
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AI summary
There is provided a device for performing one or more fluid flow tests and a method of performing a fluid flow test using the device. The device comprises a housing defining a flow channel having a distal end and a proximal end such that fluid flowing from the proximal end to the distal end flows in a first direction. The device further comprises a first pitot tube comprising a first port in fluidic communication with the flow channel, the first port facing in a second direction that is opposite to the first direction; and a second port in fluidic communication with the flow channel, the second port not facing in the second direction. The device further comprises a first sensor assembly for measuring the difference between the pressure at the first port and the pressure at the second port; and a second sensor assembly for measuring the difference between the pressure at the first port and the pressure at the second port. The first sensor assembly is sensitive to a range of pressure or differential pressure that is higher than the range that the second sensor assembly is sensitive to.