Bubble-Actuated Microfluidic Valve for Reliable Capillary Closure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing microfluidic valves face reliability issues and fabrication complexities due to the use of moving parts, making them unreliable and difficult to manufacture.
Innovation Solution
The development of microfluidic valves that utilize a firing chamber with a thermal resistor to generate a bubble, expelling liquid and forming menisci across ports to create a capillary break, which inhibits backflow and maintains the valve in a closed state, with optional features like heaters to evaporate liquid remnants and prevent inadvertent opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If moving parts are used in microfluidic valves, then the valve can control liquid flow, but the fabrication becomes complex and reliability decreases
Solution Approach 1:
The patent removes moving parts from the microfluidic valve structure entirely. Instead of using mechanical components to control flow, the invention uses a thermal resistor to generate a bubble that expels liquid through a port, creating a meniscus that blocks flow. This extraction of moving parts eliminates fabrication complexity while maintaining valve functionality and improving reliability.
Solution Approach 2:
The patent replaces the mechanical system of moving parts with a thermal field-based system. A thermal resistor generates heat to create a bubble that mechanically expels liquid, and the resulting meniscus provides the blocking function. This substitution eliminates the need for mechanical moving parts, simplifying fabrication and improving reliability.
2Ease of manufacture
If moving parts are used in microfluidic valves, then the valve can control liquid flow, but the fabrication becomes difficult
Solution Approach 1:
The patent removes moving parts from the microfluidic valve structure entirely. Instead of using mechanical components to control flow, the invention uses a thermal resistor to generate a bubble that expels liquid through a port, creating a meniscus that blocks flow. This extraction of moving parts eliminates fabrication complexity while maintaining valve functionality and improving reliability.
Solution Approach 2:
The patent replaces the mechanical system of moving parts with a thermal field-based system. A thermal resistor generates heat to create a bubble that mechanically expels liquid, and the resulting meniscus provides the blocking function. This substitution eliminates the need for mechanical moving parts, simplifying fabrication and improving reliability.
3Reliability
If a thermal resistor is used to generate a bubble for valve closure, then the valve closure becomes reliable, but energy consumption increases
Solution Approach 1:
The patent utilizes the phase transition of liquid to gas through the thermal resistor. The thermal resistor heats the liquid to generate a bubble (phase change from liquid to vapor), which then expels the liquid column and creates a meniscus for valve closure. This phase transition mechanism provides reliable closure while the thermal resistor can be designed to operate efficiently with controlled energy input.
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 solution enhances the reliability and ease of fabrication of microfluidic valves by ensuring consistent closure and preventing unintended opening, improving the overall performance and stability of microfluidic systems.
Implementation Method 1
a thermal resistor to close the valve. The thermal resistor generates a bubble in a firing chamber
Implementation Method 2
generates a bubble in a firing chamber that is sufficiently large such that liquid in the firing chamber is sufficiently expelled to break any continuous string or stream of liquid
Implementation Method 3
The ports are sized such that menisci form across each of the ports upon collapse of the bubble. The menisci inhibit liquid from flowing back into the firing chamber, maintaining the capillary break
Implementation Method 4
heaters to evaporate liquid remnants and prevent inadvertent opening
Data Source
AI summary
A microfluidic valve may include a firing chamber having an orifice, a first portion of a liquid conduit connected to the firing chamber at a first port, a second portion of the liquid conduit connected to the firing chamber at a second port and a thermal resistor. The thermal resistor is to form a bubble within the firing chamber to expel liquid from the firing chamber through the orifice such that a first meniscus forms across the first port and a second meniscus forms across the second port to interrupt liquid flow between the first portion and the second portion of the liquid conduit.