MEMS Silicon Microvalve Layout for Predictable Thermal Actuation
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Solution Overview
Problem
Conventional microvalves face issues with unpredictable actuation due to material thermal expansion mismatches, leading to stress in the solder interface and potential failure, especially when fluid flow ports are located on both ends of the valve.
Innovation Solution
A microvalve design featuring a displaceable member with elongated control arms and a balanced actuator system that allows for configurable operation as either normally open or closed, with all fluid ports located on one side to mitigate thermal expansion mismatches and improve fluid flow balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fluid flow ports are located on both ends of the valve ribs, then the valve can control fluid flow bidirectionally, but material thermal expansion mismatches occur causing unpredictable actuation and solder interface stress
Solution Approach 1:
The patent relocates all fluid flow ports to one end of the valve body, creating an asymmetric port configuration. This asymmetric design positions ports away from the thermal expansion critical zones of the ribs, eliminating the thermal expansion mismatch issues that plagued the symmetric bidirectional port design while maintaining reliable actuation and solder interface integrity
2Strength
If material thermal expansion mismatches occur in the ribs, then the valve structure experiences stress, but this causes unpredictable actuation and solder failure
Solution Approach 1:
The patent extracts the fluid flow ports from their problematic location on the ribs and relocates them to the valve body end. This extraction removes the source of thermal expansion mismatch stress from the rib structure, eliminating the chain reaction that led to unpredictable actuation and solder failure while preserving the structural integrity of the ribs
3Reliability
If the valve is configured as normally closed with control arms blocking ports, then fluid flow is prevented when closed, but actuation force requirements increase
Solution Approach 1:
The patent inverts the default valve state configuration by implementing a normally open design where the control arms in their resting position do not block the fluid flow ports. Actuation is required only to close the valve, which reduces the actuation force requirements compared to a normally closed design while maintaining precise flow control capability through the control arm blocking mechanism
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 design enhances fluid flow control by reducing actuation-induced stress and improving flow balance, allowing for reliable operation across a range of pressures and positions, with reduced force requirements for fluid flow, thus preventing premature opening or failure.
Implementation Method 1
material thermal expansion mismatches in the ribs may occur and cause actuation of the valve in unpredictable ways
Data Source
AI summary
A microvalve includes a first plate having a surface defining an actuator cavity. A second plate has a surface that abuts the surface of the first plate and includes a displaceable member that is disposed within the actuator cavity for movement between a closed position, wherein the displaceable member prevents fluid communication through the microvalve, and an opened position, wherein the displaceable member does not prevent fluid communication through the microvalve. An actuator is connected to the displaceable member. The displaceable member includes a sealing portion having a plurality of elongated control arms extending inwardly from one end thereof, wherein the control arms are configured as a valve closing members for each of a plurality of fluid flow openings in the first plate.