Soluble Matrix Capillary Filtration for Pressure Spike Elimination
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Solution Overview
Problem
Filtration systems, particularly in medical diagnostic applications, face challenges with transient pressure spikes when initially passing liquid through filters, which is difficult to manage in low-cost, handheld, disposable systems due to capillary forces associated with hydrophobic or hydrophilic filter materials.
Innovation Solution
Employing a soluble matrix with higher capillarity than the initial filter, which dissolves in the liquid, allowing capillary forces to draw the liquid out of the filter without additional pressure, and strategically placing a venting duct to exclude the soluble matrix from the collected filtrate, reducing interference in downstream processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a hydrophobic filter material is used, then liquid flow resistance is reduced for steady state operation, but initial pressure spike increases due to capillary forces
Solution Approach 1:
A surfactant is introduced as an intermediary substance that modifies the surface properties of the filter material. The surfactant reduces the contact angle between the liquid and the hydrophobic filter, thereby reducing capillary pressure and the initial pressure spike while maintaining the hydrophobic character for steady-state flow resistance
Solution Approach 2:
The surface energy parameters of the filter material are changed by applying a surfactant treatment. This modifies the contact angle and surface tension characteristics, allowing the filter to transition from high capillary pressure state to lower capillary pressure state while maintaining its filtration performance
2Stress or pressure
If a hydrophilic filter material is used, then initial pressure spike is reduced, but liquid flow resistance increases for steady state operation
Solution Approach 1:
The surface energy parameters of the filter material are precisely controlled to achieve an optimal balance. By adjusting the contact angle and surface tension characteristics, the filter maintains sufficient capillary action to reduce initial pressure spike while preserving adequate pore openness for steady-state flow rate
3Manufacturing precision
If small pore size is used, then filtration precision is improved, but capillary forces increase causing higher pressure requirements
Solution Approach 1:
A surfactant is introduced as a mediator that acts at the liquid-filter interface. It reduces the surface tension effects in small pores, thereby maintaining the fine filtration precision of small pore sizes while significantly reducing the capillary pressure that would otherwise require high operating pressures
4Productivity
If filter pore structure is optimized for flow, then productivity is improved, but capillary control capability is reduced
Solution Approach 1:
The surfactant serves as a controllable intermediary that modulates capillary forces. It allows the filter pore structure to be optimized for high flow rates while the surfactant provides dynamic control over capillary pressure, ensuring reliable operation across different flow conditions
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 method eliminates the need for initial pressure spikes, enables efficient liquid extraction from filters without mechanical intervention, and ensures cleaner filtrates by managing capillary forces, making the process more efficient and cost-effective for medical diagnostics.
Implementation Method 1
a soluble matrix in physical contact with at least a portion of a downstream surface of the at least one filtration membrane, the soluble matrix possessing a capillary drawing force sufficient to draw filtrate through the at least one filtration membrane
Implementation Method 2
the soluble matrix possessing a capillary drawing force sufficient to draw filtrate through the at least one filtration membrane and into the soluble matrix, causing the soluble matrix to at least partially dissolve or disintegrate in the filtrate
Implementation Method 3
at least one filtration membrane, and a soluble matrix in physical contact with at least a portion of a downstream surface of the at least one filtration membrane
Data Source
AI summary
Disclosed is a device for extracting a filtrate from a liquid sample that includes one or more filtration membranes and, in physical contact with a portion of the downstream surface(s) of the filtration membrane(s), a soluble matrix possessing a capillary drawing force sufficient to draw filtrate through the at least one filtration membrane and into the soluble matrix, causing the soluble matrix to at least partially dissolve or disintegrate in the filtrate, whereby the filtrate is released. Various configurations, including device configurations having two filtration membranes with a soluble matrix in between or having a tubular filtration membrane at least partially surrounding or surrounded by a soluble matrix are described.