Microstructured Microvalve Biasing for Tight Closure and Full Stroke
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Solution Overview
Problem
In microdosing technology, piezo-actuated microvalves face challenges in achieving precise fluid flow control and secure closure in the unactuated state due to asymmetrical force/deflection capacity and manufacturing tolerances, leading to issues with valve tightness and stroke length, which complicates the design and increases production costs.
Innovation Solution
A microstructured fluid flow control device with a substrate featuring a piezo-actuated first membrane and a second mechanically biased membrane, where the biasing force from the second membrane acts as a restoring force to ensure the microvalve closes in the unactuated state, allowing for a normally-closing and self-blocking functionality while tolerating manufacturing tolerances, thus simplifying the design and reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the tappet is fixed directly to the actuator membrane to eliminate idle travel, then the stroke efficiency is improved, but manufacturing tolerances cause the valve flap to remain slightly open compromising tightness
Solution Approach 1:
A biasing element is introduced as an intermediary component between the actuator membrane and the tappet. This biasing element applies a pre-force to the tappet in the closed position, ensuring that even with manufacturing tolerances, the valve flap remains tightly closed when the actuator membrane is in its neutral position. The biasing element acts as a mediator that compensates for dimensional variations without requiring direct contact between the membrane and tappet.
2Reliability
If a distance is created between the actuator membrane and valve flap to ensure closure, then valve tightness is improved, but the stroke length is reduced due to manufacturing tolerances
Solution Approach 1:
The biasing element serves as a mechanical intermediary that transmits force from the actuator membrane to the tappet while maintaining a controlled distance. This allows the valve flap to be positioned at an optimal distance from the membrane for tight closure, while the biasing element compensates for the distance through its pre-applied force, effectively extending the functional stroke length without compromising sealing.
Solution Approach 2:
The biasing element applies a preliminary force to the tappet in the closed position before actuation occurs. This pre-positioning ensures that the valve is already tightly closed due to the biasing force, and the actuator membrane only needs to overcome this pre-force to open the valve, effectively utilizing the full stroke length for valve opening rather than first establishing contact.
3Reliability
If manufacturing tolerances are minimized to ensure proper valve closure, then valve tightness is improved, but production costs increase
Solution Approach 1:
The invention changes the force parameter by introducing a biasing element that applies a pre-force to ensure valve closure. Instead of relying on precise dimensional parameters (which would require tight manufacturing tolerances), the solution uses a force-based approach where the biasing element compensates for dimensional variations, allowing for more relaxed manufacturing tolerances and lower production costs.
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 device achieves reliable fluid channel closure with reduced manufacturing tolerance requirements, enabling cost-effective production and precise control of fluid flow, with the added benefit of being normally-closing and self-blocking, independent of fluid flow direction.
Implementation Method 1
a piezo-actuated first membrane (101) arranged on a first substrate side (111)
Implementation Method 2
a second membrane (102) arranged on the first substrate side (111) and spaced apart from the first membrane (101)... which is joined to the microvalve (105) and mechanically biased towards the first membrane (101)
Data Source
AI summary
A microstructured fluid flow control device includes a substrate with a piezo-actuated first membrane arranged on a first substrate side, and a fluid channel that extends through the substrate between the first substrate side and an opposite second substrate side. In addition, the microstructured fluid flow control device includes a microvalve that extends through the fluid channel and is configured to close the fluid channel in an unactuated state, and a second membrane arranged on the first substrate side and spaced apart from the membrane and arranged between the fluid channel and the first piezo-actuated membrane. The second membrane is joined to the microvalve and is mechanically biased towards the first membrane so that a biasing force is applied to the microvalve, wherein the biasing force is part of a restoring force that causes the microvalve to close the fluid channel in an unactuated state.