Air-Oxygen Blender Venting for Source Gas Contamination Control
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Solution Overview
Problem
Air/oxygen blenders in medical settings often experience contamination or dilution of lower pressure source air or oxygen due to pressure variances, leading to inaccurate oxygen delivery and potential compromise in patient treatment.
Innovation Solution
An air/oxygen blender with a housing having first and second gas inlets, a proportioning valve, and an exhaust valve, where the exhaust valve is electrically actuated and periodically opens to vent gas, preventing pressure imbalances and contamination by releasing excess gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure balancing stages are used to equalize air and oxygen pressures, then gas flow stability is improved, but pressure variances can still cause contamination of lower pressure source gases
Solution Approach 1:
The patent implements periodic venting of the mixed gas chamber through a vent valve that opens at predetermined intervals to release accumulated pressure. This periodic action prevents pressure buildup that could cause backflow and contamination of the lower pressure source gases, while maintaining stable gas flow during patient delivery by closing the vent valve between venting cycles.
Solution Approach 2:
The patent introduces a decoupling mechanism that separates the mixed gas chamber from direct connection to source gas lines during venting operations. By using a vent valve as an intermediary, the system allows pressure relief without creating direct communication pathways that could contaminate source gases, effectively mediating between pressure management and contamination prevention.
2Reliability
If check valves are used to prevent reverse gas flow, then gas flow direction control is improved, but pressure imbalances can still occur leading to contamination
Solution Approach 1:
The system uses periodic venting cycles to proactively manage pressure imbalances before they can cause contamination. The vent valve opens at predetermined intervals to release excess pressure from the mixed gas chamber, preventing the buildup that would otherwise overcome check valve restrictions and cause backflow into source gas lines.
3Reliability
If continuous gas mixing is maintained to ensure steady oxygen delivery, then patient respiratory support stability is improved, but pressure accumulation can cause contamination of source gases
Solution Approach 1:
The vent valve operates periodically rather than continuously, opening at predetermined intervals to release accumulated pressure while remaining closed during patient gas delivery. This periodic operation maintains steady gas flow to patients while preventing pressure accumulation that could lead to contamination of source gases.
Solution Approach 2:
The mixed gas chamber continuously receives and delivers gas to patients through the proportioning valve and outlet, maintaining uninterrupted respiratory support. The periodic venting occurs in brief intervals that do not interrupt this continuous useful action, as the vent valve closes quickly after releasing pressure and remains closed during patient delivery.
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 effectively prevents contamination of lower pressure source gases by periodically venting gas, ensuring accurate oxygen delivery and maintaining precise FiO2 concentrations, thus enhancing the reliability of respiratory support systems.
Implementation Method 1
An exhaust valve is in fluid communication with the proportioning valve and the gas outlet and periodically opens to vent gas therefrom
Implementation Method 2
Each inlet fitting contains a duckbill check valve positioned with its valve bill pointing upwards and inwards into the blender housing to prevent possible reverse gas flow from the blender into the air or oxygen supply
Data Source
AI summary
An air/oxygen blender, optionally with an associated oxygen analyzer, is provided with an exhaust valve in fluid communication with one or more of a proportioning valve and a gas outlet which periodically opens to vent gas therefrom. The exhaust valve is preferably an electrically actuated valve, most preferably a solenoid valve, controlled by a control unit which periodically opens the exhaust valve. In another embodiment, an oxygen analyzer is provided with an exhaust valve in fluid communication with an oxygen sensing chamber. Preferably, the control unit controls the frequency of exhaust valve opening and the time period of exhaust valve opening. A method of prevention of contamination of a lower pressure source air or source oxygen connected to an air/oxygen blender is accomplished by periodically venting of gas from the exhaust valve.