Dual-Ring Check Valve Sealing for Low-Flow Leakage
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Solution Overview
Problem
Typical medical check valves are susceptible to low flow leakage when particulate becomes caught between the elastomeric seal and the seal bead, which can lead to safety risks and fluid flow issues in medical devices.
Innovation Solution
A medical fluid flow check valve assembly featuring dual sealing rings with a housing having dual seal beads and a seal with an inner and outer ring, where the outer ring is thinner and more flexible to prevent particulate from reaching the inner seal, ensuring a fully sealed position and reducing leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single seal bead is used in the check valve, then the device complexity is reduced, but low flow leakage occurs when particulate becomes caught between the seal and seal bead
Solution Approach 1:
The single seal bead is segmented into two separate seal beads (first seal bead and second seal bead) positioned at different locations. The seal is correspondingly segmented into an inner ring and an outer ring. This segmentation allows the first seal bead to engage with the inner ring while the second seal bead engages with the outer ring, preventing particulate from interfering with the sealing interface and eliminating low flow leakage while maintaining manageable device complexity through modular design
Solution Approach 2:
The sealing structure employs a nested configuration where the inner ring is positioned within the outer ring, and the first seal bead is positioned within the engagement area of the second seal bead. This nested arrangement allows the dual seal beads and dual sealing rings to work together in a compact configuration, preventing particulate from reaching the critical sealing interface while maintaining a space-efficient design that does not significantly increase overall device complexity
2Reliability
If dual seal beads are used to prevent leakage, then reliability improves, but manufacturing precision requirements increase because seal beads need to be exactly the same height to eliminate gaps
Solution Approach 1:
The two seal beads are designed with different local qualities - the first seal bead has a first height and the second seal bead has a second height, where these heights can be different from each other. Each seal bead is optimized for its specific function: the first seal bead engages with the inner ring at a specific location, while the second seal bead engages with the outer ring at a different location. This local quality differentiation eliminates the need for uniform height across both seal beads, reducing manufacturing precision requirements while maintaining effective leakage prevention through the dual sealing system
Solution Approach 2:
The sealing mechanism transitions from a single-dimension approach (single seal bead height) to a multi-dimensional approach by introducing both radial and axial dimensions. The first seal bead and second seal bead are positioned at different radial locations and can have different axial heights. The inner ring and outer ring provide corresponding engagement surfaces at these different dimensions. This dimensional expansion allows each seal bead to be optimized independently for its specific location, eliminating the constraint of requiring identical heights while ensuring gap-free sealing through the multi-dimensional sealing interface
3Reliability
If the outer ring is made thinner and more flexible, then the seal can better conform to seal beads and prevent leakage, but the structural strength of the seal decreases
Solution Approach 1:
The seal is designed with non-uniform local quality through the differential thickness of the inner ring and outer ring. The outer ring is made thinner and more flexible to enable better conformance to the second seal bead and effective sealing at that interface, while the inner ring maintains a greater thickness to provide the structural strength and rigidity needed for the inner sealing interface. This local quality differentiation allows each region of the seal to be optimized for its specific functional requirement - flexibility for sealing conformability where needed, and strength for structural integrity where needed
Solution Approach 2:
The seal is segmented into two distinct rings with different thickness profiles - the inner ring with greater thickness for strength, and the outer ring with lesser thickness for flexibility. This segmentation allows the seal to exhibit different mechanical properties at different radial locations, with the thicker inner ring providing overall structural support and the thinner outer ring providing conformability for effective sealing against the second seal bead, thereby resolving the contradiction between strength and sealing conformability through distributed functional specialization
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 dual sealing ring design effectively prevents low flow leakage by ensuring the inner seal can fully close, enhancing safety and reducing risks in medical fluid flow applications.
Implementation Method 1
the outer ring is thinner and more flexible to prevent particulate from reaching the inner seal
Data Source
AI summary
Check valve assemblies for fluid flow sets and devices are provided. The check valve assembly includes a housing having an inlet body and an outlet body. The inlet body includes a fluid inlet, a first seal bead having a first height, a second seal bead having a second height and a central channel. The outlet body includes a fluid outlet and a stem having a centering post, the centering post received by the central channel of the inlet body. A seal has an inner ring with a first thickness and an outer ring with a second thickness less than the first thickness. The inner ring is engaged with the first seal bead and the outer ring is engaged with the second seal bead in a fully sealed position of the check valve assembly. Fluid flow sets and methods for manufacturing check valve assemblies are also provided.