Microvalve Membrane and Ball Seal for Repeatable Port Closure
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Solution Overview
Problem
Existing microvalves with elastomeric bases face challenges in independent operation due to elastic force transmission, leading to sealing performance issues and fluid leakage, especially when used for repeated rotations or high revolutions, and are prone to fluid contamination due to adsorption or absorption effects.
Innovation Solution
A microvalve design featuring a hard base, clamping plate, membrane, ball bearing, and drive head, where the membrane is clamped over a recess with a spherical cap surface, allowing for flexible sealing and reduced elastomeric material exposure to minimize adsorption and absorption effects, with a drive head that selectively drives the ball bearing to flex the membrane for port closure and reopening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an elastomeric base is used to enable sealing of fluid channels, then sealing capability is improved, but elastic force transmission between neighbouring valves impairs valve seal performance and requires further spacing or calibration
Solution Approach 1:
The elastomeric base is segmented into individual valve regions by rigid walls that extend vertically to form channel walls. This segmentation isolates the elastic deformation of each valve region, preventing force transmission to neighbouring valves while maintaining effective sealing at each valve location.
Solution Approach 2:
The valve assembly uses a composite structure combining rigid materials (for the base, walls, and channel structure) with elastomeric material (for sealing surfaces and membrane portions). This composite approach provides both the structural integrity needed to prevent force transmission and the elastic properties needed for effective sealing.
2Reliability
If ball bearing force is increased to ensure seal, then sealing performance is improved, but drift in sealing performance occurs upon repeated rotation resulting in fluid leakage
Solution Approach 1:
A spring-loaded mechanism is incorporated into the valve actuation system that maintains constant contact force between the ball bearing and the membrane throughout repeated operations. The spring compensates for wear and deformation, ensuring consistent sealing force is applied before each actuation cycle, thereby preventing drift in sealing performance over time.
3Reliability
If elastomeric materials are used for base or channels to permit full pinching effect, then sealing effectiveness is improved, but adsorption or absorption of soluble factors results in uncontrolled changes to fluid composition
Solution Approach 1:
The elastomeric material is used only in localized sealing surfaces and membrane portions where pinching action is required, rather than throughout the entire channel structure. The bulk of the fluid pathway is constructed from non-reactive rigid materials that do not adsorb or absorb fluid components, thereby minimizing fluid composition changes while maintaining effective sealing at critical locations.
4Ease of operation
If valves are spaced further apart to mitigate elastic force transmission, then independent valve operation is improved, but apparatus size increases
Solution Approach 1:
The base is divided into discrete valve regions by rigid walls that act as force barriers. This segmentation allows valves to be positioned closer together while maintaining independent operation, as the rigid walls prevent elastic force transmission between adjacent valve regions despite the reduced spacing.
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 design provides robust and repeatable sealing, reduces fluid contamination, and allows for efficient fluid mixing and distribution with improved durability and reduced need for calibration, enabling reliable operation over long run times and high rotations.
Implementation Method 1
the membrane is flexible for enabling the unclamped part of it to be flexed into the recess
Implementation Method 2
the drive head is behind the ball bearing for selective driving of the ball bearing against the membrane to flex the membrane into the recess
Data Source
AI summary
A microvalve comprising a hard base 14, a clamping plate 12, an inlet port 96, 98, an outlet port 96, 98, a membrane 16, a ball bearing 18 and a drive head 20; whereinthe hard base comprises a recess over which the membrane is clamped by the clamping plate, the recess defining a cup with a generally spherical cap shaped surface and a perimeter, both of the inlet and outlet ports being in the recess, and at least one of them being in the generally spherical cap shaped surface; whereinthe membrane extends across the recess and is clamped thereover, and it is flexible for enabling the unclamped part of it to be flexed into the recess by the ball bearing in the clamping plate on the other side of the membrane to the recess upon actuation by the drive head behind the ball bearing for selective driving of the ball bearing against the membrane to flex the membrane into the recess as the membrane flexes around part of the ball bearing to move the membrane from a condition in which both ports are open to a port closing condition, the port closing condition being where the membrane has been flexed to extend over either one of, or alternatively both of, the input port and the output port, and clamped thereagainst by the ball bearing.