Polymer Check Valve with Thermal Deformation for Microfluidic Sealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing miniaturized check valves for micropumps and lab-on-chip systems face challenges in achieving low leakage rates due to imperfections at structuring edges and increased production costs associated with additional process steps for prestressing, which can lead to burrs and material redeposition, affecting the valve's sealing efficiency.
Innovation Solution
A normally closed check valve is produced using a polymer layer system where the deformation of a movable polymer film ensures a plane-parallel sealing element, eliminating the need for additional structuring near the valve seat and allowing for cost-effective mass production, with a single process step for prestressing and a defined stop to prevent fatigue, achieving low or no leakage rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an additional layer is applied to the valve seat to prestress the valve head, then the valve achieves normally closed function, but the production process becomes complex and costly
Solution Approach 1:
The patent changes the physical state of the polymer film by applying heat and pressure to create permanent deformation. This transforms the film from a flat state to a pre-deflected state that exerts prestress on the valve seat, achieving normally closed function without additional layers
Solution Approach 2:
The patent replaces the mechanical approach of adding prestress layers with a thermal-mechanical process. By applying heat and pressure during manufacturing, the polymer film is permanently deformed to create the prestress effect, substituting complex mechanical layering with a controlled thermal processing step
2Ease of manufacture
If micro-punching or laser structuring is used to produce the valve head, then the valve can be manufactured, but imperfections such as burrs and material redeposition occur leading to increased leakage
Solution Approach 1:
The patent changes the physical state of the polymer material through controlled melting and deformation. By heating the polymer film to its melting point and applying pressure, the material flows smoothly to form the valve head and sealing surfaces without generating burrs or redeposition, achieving high manufacturing precision
Solution Approach 2:
The patent utilizes the phase transition of the polymer material from solid to liquid state during processing. The polymer film is heated to melt and then cooled to solidify, forming precise valve structures and smooth sealing surfaces without the defects associated with mechanical or laser structuring
3Ease of manufacture
If a through-hole is created by milling or injection molding, then the valve structure can be formed, but burrs are generated that cause leakage
Solution Approach 1:
The patent uses melting and solidification phase transitions to form the through-hole and valve structures. The polymer material is heated to melt, allowing clean formation of holes and channels, then cooled to solidify with smooth edges free of burrs, achieving high edge quality
Solution Approach 2:
The patent replaces mechanical milling or injection molding processes with thermal processing. By using heat to melt and reshape the polymer material, the process eliminates the burr-generating mechanical cutting actions while maintaining ease of manufacturing complex valve structures
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 solution achieves very low leakage rates, tolerance to adjustment errors, and short response times with minimal dead volume, while avoiding the need for additional layers and complex process steps, making it suitable for mass production and ensuring reliable valve function.
Implementation Method 1
a) at least partially plastic deformation of a deformation area (40) of the polymer film (20) adjoining the connection area (30)
Implementation Method 2
a) at least partially plastic deformation of a deformation area (40) of the polymer film (20) adjoining the connection area (30) by heating the polymer film (20)
Implementation Method 3
The deformation of the movable polymer film ensures a sealing element that is plane-parallel to the valve seat, which is why very low or no leakage rates in the blocking direction can be achieved
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3C
AI summary
The method involves forming a through-hole (50) in a deformation region by melting a specific portion of the deformation region, and forming a sealing layer (60) in the deformation region around the through-hole. A polymer layer (70) is connected with a polymer film (20). A valve chamber (80) with a predetermined height is formed between the deformation region and the polymer layer. The sealing layer is pressed onto the polymer layer by partial elastic deformation of the deformation region to block a fluid connection between the valve chamber and the through-hole. An independent claim is also included for a normally-closed check valve for micro-fluidic device of a polymeric coating system.