Capillary Valve for Glaucoma Drainage with Cracking Pressure Control
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Solution Overview
Problem
Existing glaucoma drainage devices (GDDs) suffer from poor intraocular pressure (IOP) control due to lack of flow resistance and unpredictable valve functioning, which can lead to irreversible vision loss if not adequately managed.
Innovation Solution
A capillary fluid flow valve with a chamber defined by angled hydrophobic surfaces, featuring an inlet port, an outlet port, and an air vent port, which utilizes capillary action to regulate fluid flow by maintaining an air-water interface, allowing drainage only when the pressure differential exceeds a designated cracking pressure, thus controlling IOP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional valve mechanism is used to control fluid drainage, then flow regulation capability is improved, but device complexity and reliability are worsened due to moving parts
Solution Approach 1:
The patent replaces traditional mechanical valve mechanisms with a capillary action-based flow control system. The capillary channels utilize surface tension and wettability properties to regulate fluid flow without moving parts, eliminating the complexity and reliability issues associated with mechanical valves while maintaining flow regulation capability.
Solution Approach 2:
The invention employs capillary hydraulic principles where the capillary channels' dimensions and surface properties create pressure-dependent flow resistance. The flow rate is controlled by the balance between capillary pressure and hydrostatic pressure, providing automatic flow regulation based on fluid level without mechanical intervention.
2Reliability
If capillary action is used to control fluid flow, then reliability is improved by eliminating moving parts, but flow resistance control precision is worsened
Solution Approach 1:
The patent applies different wettability properties to different regions of the capillary channels. By making specific zones hydrophilic or hydrophobic, the system creates localized flow resistance characteristics that can be precisely controlled. This allows different sections of the same capillary structure to have different flow control functions, achieving precise overall flow resistance control through local property variation.
Solution Approach 2:
The invention controls flow resistance by varying physical parameters of the capillary channels, including diameter, length, and surface energy characteristics. By adjusting these parameters during manufacturing, the system achieves precise flow control without mechanical moving parts, maintaining both reliability and control precision.
3Ease of operation
If the gap between surfaces is reduced to enhance capillary action, then flow control capability is improved, but manufacturing precision requirements are worsened
Solution Approach 1:
The patent utilizes porous materials with controlled pore sizes to create the capillary channels. The porous structure naturally provides the necessary capillary action through its inherent pore geometry, eliminating the need for precisely machined narrow gaps. This approach maintains flow control capability while significantly reducing manufacturing precision requirements.
Solution Approach 2:
The invention employs composite material structures that combine different materials with complementary properties to achieve the desired capillary characteristics. By selecting materials with appropriate surface energies and structural properties, the system achieves effective flow control through material selection rather than relying solely on precise dimensional control of narrow gaps.
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 capillary valve effectively regulates fluid flow by opening at a specific cracking pressure, providing predictable and reliable IOP control without moving parts, suitable for use in GDDs to alleviate elevated intraocular pressure.
Implementation Method 1
The first and second boundary surfaces may be spaced apart by a gap sized to invoke capillary action between the surfaces
Implementation Method 2
In one aspect, the opposing surfaces are hydrophobic surfaces
Data Source
AI summary
A capillary fluid flow valve may include a chamber having a first boundary surface and a second boundary surface defined by a housing. The first and second boundary surfaces may be spaced apart by a gap sized to invoke capillary action between the surfaces. The first surface may be angled relative to the second surface. The chamber may have an inlet port, an outlet port, and an air vent port. The gap at the air vent port may be smaller than the gap at the outlet port and the gap at the outlet port may be smaller than the gap at the inlet port.