Notched Ferrule Elastic Deformation for High-Pressure Sealing
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Solution Overview
Problem
Conventional tube fittings face challenges in achieving a reliable seal, especially with high-pressure metal tubing due to its hardness and resistance to deformation, often requiring additional elastomeric seals to prevent leakage.
Innovation Solution
A ferrule seal assembly with a cylindrical tube featuring a circumferential notch and a tube gripping member with elastic deformability, allowing the ferrule to bend and form a secure seal with the tube end, complemented by a transverse shoulder and camming surface for enhanced sealing and shock absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ferrule fittings are used with high-pressure metal tubing, then the tubing can be connected to a body, but the seal is less than adequate and requires additional elastomeric seals to prevent leakage
Solution Approach 1:
The patent extracts the sealing function from a separate elastomeric seal component and integrates it directly into the ferrule structure itself. The ferrule includes an integrated sealing surface and sealing portion that directly contacts the tube end, eliminating the need for separate elastomeric seals while achieving adequate sealing performance.
Solution Approach 2:
The patent merges the gripping function and sealing function into a single integrated ferrule component. The ferrule simultaneously grips the tube end through its gripping portion and seals against the tube end through its integrated sealing portion, combining multiple functions that were previously performed by separate components.
2Strength
If heavy wall metal tubing is used for high-pressure applications, then the tubing can withstand pressure, but it is difficult to grip and deform plastically to achieve desired tube grip
Solution Approach 1:
The patent applies local quality by creating a notched portion in the ferrule at the specific location where tube gripping is needed. The notch creates a localized stress concentration point that facilitates plastic deformation of the ferrule material at that specific spot, allowing the ferrule to grip the hard metal tubing without requiring deformation of the tubing itself.
Solution Approach 2:
The patent changes the physical parameters of the ferrule by introducing a notch that alters the stress distribution and deformation characteristics. The notch modifies the ferrule's mechanical properties locally, enabling controlled plastic deformation at the gripping interface while maintaining the overall structural integrity needed to withstand high pressures.
3Ease of operation
If a threaded pull-up mechanism is used to install the ferrule, then the ferrule can be positioned on the tube end, but the seal between the tube and body is still inadequate
Solution Approach 1:
The patent applies preliminary action by pre-forming the sealing surface and sealing portion on the ferrule during manufacturing, before installation. The ferrule is pre-configured with the correct geometry and surface characteristics needed for sealing, so that when installed using the threaded pull-up mechanism, the sealing function is immediately effective without requiring additional sealing components or complex sealing procedures.
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 ferrule seal assembly provides a high-performance, leak-proof connection that withstands vibrations, pulsations, and pressure, maintaining seal integrity through elastic deformations and secondary sealing mechanisms, effectively addressing the limitations of conventional fittings.
Implementation Method 1
a tube gripping member with elastic deformability, allowing the ferrule to bend and form a secure seal with the tube end
Data Source
AI summary
A tube-fitting-assembly ferrule apparatus and method to secure connections between tubing sections against high pressure, vibration, pulsation, and hammering, by providing a tube-fitting-assembly ferrule which elastically deforms in use, securing the primary circumferential point seal with a shock-absorbing and shape-retaining force.