Sealed Microfluidic Conduit Assemblies with Radial Compression

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Solution Overview

Problem

Conventional fluid connections in microfluidic applications, such as ferrules and adhesives, are bulky, have short service life under high pressures, and fail to provide robust sealing between conduits of dissimilar materials or sizes, especially in low-flow regimes requiring precise signal resolution.

Innovation Solution

A method involving a malleable material layer surrounded by a jacket, where radial compression forms a fluid-tight seal between conduits, eliminating the need for ferrules and adhesives, and allowing connections between conduits of different materials and sizes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If ferrules and machined fittings are used for connecting conduits, then connections can be made between conduits, but the connections become bulky and unsuitable for tight spaces

Engineering Contradiction:

Improveinstallation in tight spacesVSAvoidconnection size

Core Design Contradiction:

Ease of operationVSVolume of moving object

Solution Approach 1:

The invention embeds the sealing function directly within the conduit wall structure itself, nesting the sealing mechanism inside the conduit rather than adding external fittings. This eliminates bulky external connectors while maintaining sealing capability in tight spaces.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The invention merges the conduit structure with the sealing function by integrating a sealing layer directly into the conduit wall. This combination eliminates the need for separate ferrules or fittings, reducing overall connection volume while maintaining operational capability.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If ferrules and adhesives are used for connecting conduits, then connections can be made, but the service life is insufficient under very high fluid pressures

Engineering Contradiction:

Improveservice life under high pressureVSAvoidconnection strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The invention employs composite conduit walls with distinct functional layers: an inner conduit layer, an intermediate sealing layer with specific hardness properties, and an outer structural layer. This composite structure provides both the strength needed for high-pressure applications and the sealing capability for reliable long-term service.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention applies different material properties to different regions of the conduit wall. The sealing layer has specific hardness characteristics (softer than the outer layer) localized at the connection point, while the outer layer maintains high strength throughout. This localized differentiation enables both high-pressure resistance and effective sealing.

Inventive Principle:

Principle #3Local quality

3Reliability

If conventional connections are used, then conduits can be connected, but sealing integrity is insufficient in low-flow applications with small inside diameters

Engineering Contradiction:

Improvesealing integrityVSAvoidinside diameter precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The invention changes the hardness parameter of the sealing layer relative to the outer conduit layer, making the sealing layer softer. This parameter difference enables the softer sealing layer to deform and conform to mating surfaces, creating reliable seals in small-diameter conduits without compromising the precision of the inside diameter.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Inventive Principle:

Principle #3Local quality

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 provides durable, fluid-tight connections capable of withstanding high pressures and ensuring minimal signal dispersion, suitable for microfluidic applications, including HPLC and electrospray probes, with scalable and cost-effective fabrication.

Implementation Method 1

compressing the layer of malleable material against the joint to fluidly seal the joint, by applying a radial force to an outer surface of the jacket at an axial distance from the joint

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 2

the layer of malleable material has a lower hardness than the first conduit, the second conduit and the jacket

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Data Source

PatentUS8727231B2Sealed microfluidic conduit assemblies and methods for fabricating them

Publication Date: 2014.05.20 DH TECH DEVMENT PTE

AI summary

A sealed microfluidic conduit assembly is fabricated by forming a joint through which a first conduit fluidly communicates with a second conduit, by bringing the first conduit into contact with the second conduit. A layer of malleable material surrounding one or both conduits is compressed against the joint to fluidly seal the joint, by applying a radial force to an outer surface of a jacket surrounding the conduits and malleable layer. The respective compositions and/or sizes of the first conduit and second conduit may be different.