Airway Adapter Liquid Separator for Fast, Blockage-Resistant Sampling
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Solution Overview
Problem
Conventional breathing gas sampling systems face issues with water condensation and other liquid substances blocking the sampling tube, leading to increased system response and rise times, and creating flow resistance that affects gas exchange in the lungs.
Innovation Solution
A liquid separator with a porous membrane integrated into the airway adapter that separates liquids from the breathing gas close to the patient, using a supporting structure to minimize turbulence and blockage, with a removable connection to maintain gas flow integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the diameter of the sampling tube is decreased to reduce system response and rise times, then the system response time and rise time are improved, but the condensed water and other liquid substances block the sampling tube easily, deteriorating the measurement system performance or preventing gas analysis
Solution Approach 1:
The invention extracts the liquid separation function from the sampling tube by integrating a liquid separator with a hydrophobic membrane into the airway adapter. This allows the sampling tube to maintain its small diameter for fast response while the liquid separator removes condensed water and liquid substances before they can block the tube, thus resolving the contradiction between fast response time and reliable operation.
Solution Approach 2:
The liquid separator with hydrophobic membrane acts as an intermediary component between the breathing circuit and the sampling tube. It mediates the conflict by allowing gas molecules to pass through to the sampling tube while blocking liquid substances, enabling the small-diameter tube to function reliably without direct exposure to condensed water.
2Reliability
If a cylindrical water separation unit is located partially inside the airway adapter breathing flow path, then liquid separation is achieved, but high and unwanted flow resistance is generated to the gas flow, disturbing gas exchange in the lungs
Solution Approach 1:
The liquid separator is designed with a hydrophobic membrane that has selective permeability - it allows gas molecules to pass through freely while blocking liquid substances. This local quality of the membrane material enables liquid separation without generating significant flow resistance to the breathing gas, resolving the contradiction between separation capability and gas flow efficiency.
3Loss of time
If the sampling gas flow speed is increased to decrease system response and rise times, then the response time is improved, but the sampling gas flow speed is typically kept below 200 ml/min (advantageously approximately 50 ml/min) to enable gas monitoring of small patients with low tidal volumes
Solution Approach 1:
The invention segments the sampling system into two functional parts: the liquid separator that handles liquid removal, and the sampling tube that handles gas transport. This segmentation allows the sampling gas flow to be optimized for small patients (low flow rate) while the liquid separator prevents blockages, enabling reliable operation at low flow rates without sacrificing response time.
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 reduces system response and rise times, maintains gas flow efficiency, and prevents blockages, enhancing capnogram accuracy and reducing the need to disrupt the breathing circuit for maintenance.
Implementation Method 1
a liquid separator (40) for removing a liquid, such as water, from a sample of breathing gas flowing through the channel
Data Source
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AI summary
A liquid separator removing a liquid from a sample of a breathing gas flowing through an airway adapter having a channel surrounded by a wall is disclosed herein. The separator includes a chamber receiving the sample, and a membrane having an outer surface exposed to the gas flow, the membrane at least partially surrounding the chamber, which membrane separates the liquid received by the chamber. The separator also includes a supporting structure for supporting the membrane, and a connector operationally attached to the supporting structure, the connector being connectable to the adapter. The connector comprises a cavity providing a flow path for the sample from the chamber through an opening of the cavity to a sample tube. The membrane branches from a central part of the channel into at least two different branches extending to different directions. (Fig. 2)