Galvanic Oxygen Sensor Pressure Equalization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Galvanic fuel cell oxygen sensors, such as the Teledyne UFO-130-2, face issues with membrane displacement and rupture due to pressure differences, leading to inaccurate readings and short lifespan, requiring frequent recalibration and being susceptible to 'oxygen shock'.
Innovation Solution
The method involves applying an equal vacuum to both sides of the membrane using a pressure equalization port tube and sealing with Tygon tubing and RTV11 sealant to maintain equal pressures, reducing membrane displacement and enhancing sensor stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a thin or porous membrane is used to improve oxygen transfer rate, then response time is improved, but membrane strength decreases leading to displacement and rupture
Solution Approach 1:
The patent uses a thin PTFE membrane (0.005 to 0.020 inches thick) that is flexible yet sufficiently strong when properly supported. The membrane is stretched tautly across the cathode mesh and secured at the edges, creating a stable configuration that maintains both rapid oxygen transfer and structural integrity during operation.
2Productivity
If vacuum is applied to draw gas sample through the sensor, then gas flow is improved, but pressure difference causes membrane displacement and rupture
Solution Approach 1:
The patent applies vacuum to both the sample gas chamber and the electrolyte chamber simultaneously, creating equal pressure conditions on both sides of the membrane. This eliminates pressure differential that would cause membrane displacement or rupture, while still allowing gas flow through the sensor via the cathode mesh structure.
3Quantity of substance
If membrane is made porous and thin for rapid oxygen transfer, then oxygen transfer rate is improved, but membrane becomes susceptible to displacement
Solution Approach 1:
The thin PTFE membrane is stretched tautly across the cathode mesh support and secured at the edges to a flat surface, creating a stable configuration that prevents displacement while maintaining high oxygen transfer rate through its porous structure.
Solution Approach 2:
By equalizing pressure on both sides of the membrane through simultaneous vacuum application, the patent eliminates pressure-induced membrane displacement, maintaining stable membrane position while preserving rapid oxygen transfer through the porous structure.
4Measurement precision
If frequent recalibration is performed to maintain accuracy, then measurement precision is maintained, but operational time is reduced
Solution Approach 1:
By eliminating membrane displacement through pressure equalization, the patent ensures consistent oxygen transfer conditions and stable baseline readings, reducing drift and the frequency of recalibration needed to maintain measurement precision.
Solution Approach 2:
The stable, displacement-free membrane configuration ensures consistent oxygen transfer characteristics over time, maintaining measurement accuracy and reducing the operational interruptions required for recalibration.
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 approach extends the sensor's life, improves response time, and maintains accuracy by preventing membrane rupture and displacement, thus reducing false readings and the need for frequent recalibration.
Implementation Method 1
measure oxygen content of a gas or fluid by diffusing oxygen through a semipermeable membrane into an electrolyte layer
Implementation Method 2
applying an equal vacuum to both sides of the membrane using a pressure equalization port tube
Implementation Method 3
The oxygen in the sample contacts the gold cathode and is chemically reduced to hydroxyl ions
Implementation Method 4
The hydroxyl ions then flow toward the silver anode, where an oxidation reaction occurs with the silver
Data Source
AI summary
A method for improving the performance of a galvanic fuel cell type oxygen sensor comprises providing a pressure equalization port leading to the interior of an inner core housing that contains the membrane, the electrolyte and the anode and cathode electrodes and hermetically sealing the sensor housing except for its sample inlet port and its sample outlet port. By connecting the same vacuum source to both the pressure equalization port and the sample outlet port, the device's membrane is less subject to movement or rupture as gas samples are drawn in via the sample inlet port. A technique for ensuring a hermetic seal is also described.