Lateral Flow Filter with Pore Gradient for Blood Filtration
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Solution Overview
Problem
Existing filtration systems face challenges in efficiently removing bulk and fine particulates from fluids without clogging or peripheral flows, particularly in thin packages, and often require pressurized flows or poor sealing methods that lead to variable filtration efficiency and absorption of sealing compounds.
Innovation Solution
A filter system comprising two or more planar filter layers with different pore sizes, where the top filter has larger pores for initial filtration and the bottom filter has smaller pores, configured for lateral fluid flow, with a capillary cartridge system that includes a filtration chamber and a capillary outlet, utilizing a hydrophobic coating and crush lines to prevent fluid migration and enhance filtration efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single filter element is used for both gross particulate removal and fine filtration, then the device structure is simple, but the filtration efficiency is poor and the filter clogs easily
Solution Approach 1:
The filter is divided into multiple stacked filter elements with different pore sizes. The top filter element has larger pores for gross particulate removal, while the bottom filter element has smaller pores for fine filtration. This segmentation allows each filter element to perform its specific function efficiently without interfering with the other, preventing clogging and maintaining high filtration efficiency.
2Reliability
If transverse flow filtration is used to remove particulates, then particle separation is achieved, but peripheral non-filtering flows occur through small capillaries or gaps
Solution Approach 1:
The invention transitions from traditional vertical flow paths to a lateral flow path that extends horizontally across the filter elements. The elongated filter elements are positioned such that fluid enters at one end and flows laterally through the filters to exit at the opposite end. This dimensional change eliminates peripheral flows through capillaries or gaps because the entire flow path is contained within the lateral dimension, ensuring all fluid passes through the filter media.
3Volume of moving object
If conventional filters with short transverse flow paths are used, then the device is compact, but separation efficiency is poor
Solution Approach 1:
The invention extends the flow path in the lateral dimension rather than increasing the vertical thickness. Multiple filter elements are stacked horizontally with elongated dimensions, allowing the fluid to travel a long distance laterally through the filters. This maintains a compact vertical profile while achieving high separation efficiency through the extended lateral flow path.
4Reliability
If sealing materials such as glues or tapes are used to seal the filter, then the filter is sealed, but sealing quality is variable and sealing compounds are absorbed into the filter
Solution Approach 1:
The filter elements are designed with self-sealing features through their structural configuration. The lateral flow path design and stacking arrangement create natural sealing at the interfaces between filter elements and the housing, eliminating the need for external sealing materials. The filters seal themselves through proper positioning and interlocking structures, preventing peripheral flows without introducing sealing compounds that could be absorbed into the filter media.
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 configuration effectively separates particles from fluids without external forces, minimizing clogging and maximizing plasma outflow volume, while maintaining high filtration efficiency and flow rates through a thin, efficient design.
Implementation Method 1
a capillary outlet from the filtration chamber in fluid contact with the filtrate egress surface of the lower filter element
Data Source
Figure 1
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AI summary
This invention provides lateral flow filters with pore size gradients and with features to prevent peripheral flows around the filter. The filters can be laminated composites of two or more planar filter layers. Cartridges employing the filters can include a filtration chamber configured to retain the lateral flow filters including a port for sample application and a capillary channel for filtrate egress. The fluid egress port can be positioned to receive filtrate from one filter layer but not another.