Breath Sampling Port With Segmented Inlets Prevents Liquid Blockage
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Solution Overview
Problem
Existing breath sampling systems in Capnography face challenges with liquid ingress, leading to blockages and frequent adapter replacements, which disrupt the measurement of carbon dioxide concentrations in exhaled breath.
Innovation Solution
A breath sampling port design featuring multiple inlets separated by a migration path with increased surface area, and a channel system that minimizes liquid transfer between inlets, preventing blockages while maintaining smooth airflow and waveform integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single inlet sampling port is used, then the device complexity is reduced, but liquid blockages occur frequently requiring adapter replacement
Solution Approach 1:
The sampling port is divided into multiple independent inlets (first inlet, second inlet, third inlet) that are physically separated by migration paths. This segmentation allows the system to continue sampling through unaffected inlets even when liquid blocks one inlet, thereby improving reliability without significantly increasing overall device complexity.
2Volume of stationary object
If inlets are placed close together to reduce adapter size, then the adapter volume is reduced, but liquid can migrate between inlets causing blockages
Solution Approach 1:
The migration paths between inlets are designed with specifically increased surface area compared to normal pathway surfaces. This local modification of surface characteristics creates capillary pressure barriers that prevent liquid migration between inlets, allowing the inlets to be positioned closer together while maintaining reliability.
3Reliability
If the sampling tube diameter is increased to prevent blockages, then the likelihood of liquid blockage is reduced, but the waveform accuracy of carbon dioxide measurements deteriorates
Solution Approach 1:
By providing multiple separate inlets instead of a single large-diameter tube, the system achieves blockage resistance through redundancy rather than increased diameter. Each inlet maintains a small diameter suitable for waveform accuracy, while the multiple inlets collectively provide robustness against liquid blockages.
4Reliability
If filters are added to the sampling port to block liquid, then liquid ingress is prevented, but the carbon dioxide waveform measurement accuracy is degraded
Solution Approach 1:
The solution extracts and removes the filter component entirely, replacing it with a geometric design featuring multiple inlets separated by migration paths with increased surface area. This design prevents liquid ingress through capillary pressure effects rather than filtration, thereby maintaining waveform measurement accuracy while achieving liquid blockage prevention.
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 design effectively reduces the likelihood of liquid entering the sampling tube, preventing blockages and maintaining accurate carbon dioxide waveform measurements, thereby extending the lifespan of the sampling system and ensuring continuous data integrity.
Implementation Method 1
By providing a migration path with surface area substantially greater than the surface area of the second inlet the increased surface tension in the liquid substantially prevents the liquid from reaching the second inlet
Implementation Method 2
The breath sampler is typically adapted with a pump which operates to continuously create a pressure drop along the path from the airway adapter to the breath sampler. By creating the pressure drop, which may also be referred to as 'negative pressure differential,' exhaled breath samples are continuously drawn from the airway adapter through the aperture(s) into the sampling port
Implementation Method 3
The breath samplers generally employ technology based on, for example, infrared spectrography, molecular correlation spectrography, mass spectrography, Raman spectrography, or photo-acoustic spectrography, for the performance of the measurements and analyses
Data Source
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AI summary
There is provided an airway tube for breath sampling, comprising a breath sampling port comprising two or more inlets adapted to sample breath from the airway tube. The inlets are connected to each other through a junction located outside of the air passageway of the airway tube.