Capillary Connector Sleeve Sealing for Low-Dead-Volume Assembly
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Solution Overview
Problem
In high-performance liquid chromatography (HPLC) and ultra-high performance liquid chromatography (UHPLC) systems, existing fittings for capillary tubes are difficult to assemble reliably, often damaging the capillary ends and leading to issues like carry-over and dead volume, which cause peak broadening and errors in compound identification.
Innovation Solution
A connector system featuring a capillary holder with a compliant material sleeve and a deformable portion that creates a seal between the capillary tubing and the connector, allowing for reliable assembly without damaging the capillary and minimizing dead volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fittings are used to connect capillary tubes, then fluid connection is achieved, but the capillary ends are damaged or crushed during assembly
Solution Approach 1:
A compliant sleeve is introduced as an intermediary component between the capillary tube and the rigid fitting. The sleeve deforms under compression to create a seal, protecting the capillary end from direct contact with the fitting's crushing surfaces while maintaining fluid tightness.
Solution Approach 2:
The compliant sleeve is made of a flexible material that can deform elastically under compression. This flexibility allows the sleeve to conform to the capillary end and create a reliable seal without requiring rigid, potentially damaging components.
2Stress or pressure
If conventional sealing methods are used, then pressure sealing is achieved, but dead volume increases causing peak broadening
Solution Approach 1:
The sealing function is extracted from the rigid fitting structure and transferred to the compliant sleeve. This allows the sealing interface to be positioned closer to the capillary end, eliminating the need for large sealing surfaces and reducing dead volume in the connection region.
Solution Approach 2:
The sealing mechanism transitions from rigid mechanical contact to elastic deformation of the compliant material. This parameter change allows sealing at lower compression forces and with smaller contact areas, reducing dead volume while maintaining pressure integrity.
3Strength
If rigid fittings are used for high pressure connection, then pressure withstanding capability is improved, but assembly difficulty increases
Solution Approach 1:
The connection system is segmented into distinct functional components: the rigid fitting for structural strength, the compliant sleeve for sealing and protection, and the capillary tube for fluid transport. This segmentation allows each component to be optimized for its specific function while simplifying assembly through straightforward insertion and compression.
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 connector system ensures a reliable fluid connection between capillaries and conduits, reducing peak broadening and improving the accuracy of compound identification by minimizing carry-over and dead volume, while withstanding high pressures and repeated cycles.
Implementation Method 1
a deformable portion configured for deforming so that the compliant material of the sleeve in the capillary holder is deformed to create a seal between the inner capillary tubing and the connector
Data Source
AI summary
Fittings for capillaries, such as those in chromatographic systems, can be difficult to reliably assemble. The invention relates to a connector for providing a fluid connection between a capillary and a fluid conduit, said connector comprising: a capillary holder for receiving an end of the capillary, said capillary comprising inner capillary tubing, wherein the inner capillary tubing of the received end of the capillary is located within a compliant material sleeve; a deformable portion configured for deforming so that the compliant material of the sleeve in the capillary holder is deformed to create a seal between the inner capillary tubing and the connector; and a receiving portion configured to receive a fitting at an end of the fluid conduit; wherein the capillary holder and the receiving portion are connected so that the connector is configured to fluidly connect the capillary and the fluid conduit.