Dissolved Gas Sensor with Permeable Membrane for Rapid Equilibration
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Solution Overview
Problem
Current methods for measuring total dissolved inorganic carbon (DIC) in seawater are limited by slow response times, making them unsuitable for high-resolution, real-time measurements essential for capturing rapid changes in dynamic marine environments, particularly on mobile platforms like AUVs and gliders.
Innovation Solution
A system utilizing a sample processing cell with a permeable wall for concurrent or countercurrent flow between the sample and a reagent fluid, achieving rapid equilibration and allowing for continuous spectrophotometric measurements of DIC, with a response time of approximately 70 seconds for full equilibrium and 22 seconds for partial equilibrium, enabling continuous and high-resolution data collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional DIC measurement methods are used, then measurement accuracy is maintained, but response time is slow and real-time measurement capability is lost
Solution Approach 1:
The system separates the measurement process into two independent stages: (1) rapid CO2 equilibration between sample and reagent through the permeable membrane, and (2) spectrophotometric detection of the equilibrated reagent. This segmentation allows the equilibration step to proceed rapidly while the measurement step maintains high precision, resolving the contradiction between speed and accuracy.
Solution Approach 2:
A reagent fluid acts as an intermediary carrier that rapidly equilibrates with dissolved CO2 through the permeable membrane and then transports the equilibrated CO2 to the spectrophotometric detector. This intermediary enables fast response by decoupling the equilibration process from the measurement process, while maintaining measurement accuracy through controlled spectrophotometric analysis of the reagent.
2Adaptability or versatility
If conventional measurement systems are deployed on mobile platforms, then adaptability to dynamic environments is improved, but measurement resolution and data quality deteriorate due to slow response
Solution Approach 1:
The system is designed with dynamic flow control capabilities that can adapt to different mobile platforms (AUVs, gliders, ROVs). The flow rates of sample and reagent can be adjusted in real-time to optimize equilibration speed and measurement precision for each specific platform's operational conditions, maintaining high measurement resolution while adapting to diverse dynamic environments.
Solution Approach 2:
The system allows dynamic adjustment of critical parameters including flow rate, equilibration time, and spectrophotometric measurement intervals. These parameter changes enable the system to maintain optimal measurement resolution across different mobile platforms and operational conditions, resolving the contradiction between platform adaptability and measurement quality.
3Loss of time
If rapid equilibration is achieved through increased flow rates, then response time is reduced, but system complexity and energy consumption increase
Solution Approach 1:
The system employs hydraulic flow control mechanisms to achieve rapid CO2 equilibration between sample and reagent. By utilizing fluid dynamics and pressure-driven flow through the permeable membrane, the system achieves fast equilibration without requiring complex mechanical actuators or control systems, thus reducing overall system complexity while minimizing equilibration 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 system provides accurate and stable measurements of DIC with precision comparable to established methods, suitable for high-frequency observations in dynamic marine environments, enhancing the spatiotemporal resolution and reducing calculation errors in characterizing the marine CO2 system.
Implementation Method 1
a first conduit defining a first passage with at least one analyte-permeable wall capable of passing at least the pre-selected dissolved analyte from the sample liquid into a reagent fluid
Implementation Method 2
achieving rapid equilibration and allowing for continuous spectrophotometric measurements
Implementation Method 3
The quantity of the dissolved analyte in the at least partially equilibrated reagent is measured by spectrophotometry
Data Source
AI summary
A high-resolution in situ sensing system and method for providing continuous measurements of at least one dissolved analyte including a sample processing cell having at least a first conduit defining a first passage with at least one selectively-permeable wall capable of passing a portion of the sample liquid into a processing, fluid. The at least one selectively-permeable wall substantially resists flow of another portion of the sample liquid therethrough. Processing fluid is directed through the first conduit while moving the sample liquid and the reagent fluid relative to each other in one of a stationary, concurrent or a countercurrent flow relationship to achieve either partial or full equilibration between the sample liquid and processing fluid to generate at least partially equilibrated reagent fluid and a processed sample in a substantially continuous manner.