Capillary Connector Snap-Fit Sealing for Low Dead Volume

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Solution Overview

Problem

Existing capillary connectors in HPLC systems face issues with unreliable sealing, difficulty in tool-free connection and disconnection, risk of component breakage due to excessive force, and high dead volume, which are exacerbated by high pressures and small sample volumes.

Innovation Solution

A capillary connection system utilizing snap fit or bayonet mechanisms with discrete connection states, eliminating the need for threads, and incorporating a gripping element with a curved end to prevent capillary damage during disconnection, along with a sealing inlay piece for secure and low-dead-volume connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ferrule is squeezed against a conical cross-section to seal the connection, then sealing reliability is improved, but the risk of damaging the fitting increases due to large torque applied

Engineering Contradiction:

Improvesealing reliabilityVSAvoidfitting damage risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the threaded mechanical connection system with a snap-fit system using elastomeric material. The connector body is made of elastomeric material that can be inserted into the fitting and snaps into place, eliminating the need for threading and large torque application while maintaining sealing reliability through the elastomeric material's inherent compliance and sealing capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Strength

If threads are used for connection, then connection strength is improved, but tool-free operation becomes difficult

Engineering Contradiction:

Improveconnection strengthVSAvoidtool-free operation

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The patent substitutes the threaded connection system with a snap-fit mechanism using elastomeric material. The connector body is inserted into the fitting and automatically snaps into place through elastic deformation, providing strong connection without requiring threads or tools for assembly or disassembly.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If a pull out ferrule is used to detach the capillary, then capillary removal becomes possible, but the capillary can be stretched or damaged

Engineering Contradiction:

Improvecapillary detachmentVSAvoidcapillary stretching

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the pull-out ferrule mechanism with a direct snap-fit connection using elastomeric material. The elastomeric connector body is inserted into the fitting and seals against the capillary directly, allowing the capillary to be pulled out freely without the mechanical interference of a ferrule, thus preventing stretching and damage.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3258259B1Capillary connection system

Publication Date: 2025.10.22 DIONEX SOFTRON

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AI summary

The present invention relates to a socket unit (1) for a capillary connection system, especially for use in HPLC applications, said socket unit (1) comprising a housing (3) comprising a housing outer surface (32) and a housing inner surface (33) defining a housing axial cavity (31); and a socket connecting mechanism adapted to engage with a corresponding plug connecting mechanism of a plug unit (2) to connect the plug unit (2) and the socket unit (1) together, wherein the socket connecting mechanism is adapted for a predetermined number of discrete connection states between the socket unit (1) and the plug unit (2). The present invention also relates to a corresponding plug unit (2) and a system comprising the socket unit (1) and the plug unit (2).