Compression Fitting Ferrule Retention Mechanism

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Solution Overview

Problem

Current zero dead volume compression fittings in high-pressure fluidic systems, such as those used in liquid chromatography, face issues like ferrule slippage during assembly or disassembly, loss of components, and difficulty in removing the ferrule from the receiving body, especially in vertically oriented setups.

Innovation Solution

The design includes a fitting body, ferrule, and tube configuration where the ferrule is removably coupled to the fitting body using a coupling extension with a recess and projection system, preventing accidental removal and ensuring a secure fluid-tight seal by engaging the ferrule with the receiving body's threads, thus preventing ferrule slippage and loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the ferrule is left loose on the tubing for easy assembly, then the assembly process is simplified, but the ferrule can slide off the tubing during handling or insertion

Engineering Contradiction:
Improveassembly processVSAvoidferrule retention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The ferrule is preliminarily attached to the fitting body through a snap-fit coupling mechanism before the actual assembly operation. This preliminary attachment ensures the ferrule cannot slide off during handling or insertion, while still allowing for straightforward assembly by simply inserting the pre-assembled ferrule-fitring body unit onto the tubing.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the ferrule is tightly secured to the fitting body to prevent slippage, then ferrule retention is improved, but the ferrule becomes difficult to remove from the receiving body

Engineering Contradiction:
Improveferrule retentionVSAvoidferrule removal
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The coupling mechanism between the ferrule and fitting body employs a snap-fit design that provides strong retention during normal operation but allows for controlled disengagement. The ferrule can be securely retained during high-pressure operation, yet can be intentionally removed by applying sufficient force to overcome the snap-fit engagement, enabling maintenance and reconfiguration.

Inventive Principle:
Principle #15Dynamics

3Ease of repair

If the ferrule is designed to be easily removable for maintenance, then ease of repair is improved, but the ferrule may accidentally separate from the tubing during assembly or disassembly

Engineering Contradiction:
Improveferrule accessibilityVSAvoidconnection stability
Core Design Contradiction:
Ease of repairVSReliability

Solution Approach 1:

The ferrule is preliminarily attached to the fitting body through a snap-fit coupling mechanism before the actual assembly operation. This preliminary attachment ensures the ferrule cannot slide off during handling or insertion, while still allowing for straightforward assembly by simply inserting the pre-assembled ferrule-fitring body unit onto the tubing.

Inventive Principle:
Principle #10Preliminary action

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 configuration significantly reduces the occurrence of ferrule slippage and loss, ensuring reliable and leak-resistant connections, even in vertically oriented chromatographic systems, by securely retaining the ferrule on the tube and fitting body during assembly and disassembly.

Implementation Method 1

compress the ferrule against the tubing and the receiving body to provide a fluid-tight seal

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3140583B1Compression fitting with coupled ferrule
Publication Date: 2023.11.01 WATERS TECHNOLOGY CORP
  • EP3140583B1 patent drawingFigure 1A
  • EP3140583B1 patent drawingFigure 1B
  • EP3140583B1 patent drawingFigure 1C

AI summary

The invention provides compression fittings and methods of assembling compression fittings. In exemplary embodiments, compression fittings are provided that include a fitting body, a ferrule and a tube. For example, the fitting body can be removably coupled to the ferrule when the tube is disposed therethrough.