Sequential Sealing Fitting with Restoring Load
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Solution Overview
Problem
Existing fluid fittings with sequential sealing action often experience a reduction in loading force between the tube or pipe and sealing teeth due to pipe radial deformation, leading to potential gaps and diminished seal effectiveness under mechanical loads like bending and torsion.
Innovation Solution
A fitting design with a coupling body and swage ring that sequentially sets and connects a main seal, inboard seal, and outboard seal, with the swage ring applying a restoring load to the main seal after the outboard seal is connected, maintaining optimal sealing force throughout the sequence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If sequential seal engagement is used to reduce installation force, then the peak installation force is reduced, but the loading force between earlier seals and the pipe is reduced due to pipe radial deformation
Solution Approach 1:
The sealing action is segmented into three distinct sequential stages (main seal, inboard seal, outboard seal) rather than simultaneous engagement. This segmentation allows the pipe to deform progressively at each stage rather than all at once, maintaining adequate loading force at each seal while still reducing peak installation force compared to simultaneous engagement of all seals.
2Ease of operation
If sequential seal engagement is used to reduce installation force, then installation becomes easier, but gaps may form between earlier seals and the pipe under mechanical loads
Solution Approach 1:
The main seal is engaged first as a preliminary action before the inboard and outboard seals. This preliminary sealing action establishes a baseline seal that is then protected by the subsequent seals. The sequential arrangement ensures that each seal is set while the pipe is still relatively stable, preventing gap formation under subsequent mechanical loads like bending and torsion.
3Reliability
If multiple seals are engaged simultaneously, then sealing redundancy is improved, but the installation force required increases significantly
Solution Approach 1:
The sealing process uses periodic action with three distinct phases of seal engagement rather than simultaneous action. The swage ring progresses through the fitting body in stages, engaging each seal sequentially as it travels axially. This periodic engagement maintains sealing redundancy through multiple seals while distributing the installation force over time and space, significantly reducing peak force requirements compared to simultaneous engagement.
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 design reduces the peak force required for installation and maintains effective sealing by minimizing the impact of subsequent seal engagements on earlier established connections, ensuring a consistent and leak-tight connection under various mechanical loads.
Implementation Method 1
a swage ring which is forced over the fitting to compress it radially inwardly against the tube or pipe to create a seal
Implementation Method 2
The engagement of the sealing teeth of the fitting with the tube or pipe causes the pipe to be deformed radially inwardly
Data Source
AI summary
A fitting for making connections with a pipe includes a coupling body having an inside surface defining a bore for receiving a pipe. A ring is fitted over the coupling body for sealing and mechanically connecting the coupling body to the pipe. An axisymmetrical main seal is formed on the inside surface of the coupling body that seals and connects to the pipe when the ring is installed on the coupling body. An axisymmetrical inboard seal is formed on the inside surface of the coupling body axially spaced from the main seal that seals and connects to the pipe when the ring is installed on the coupling body. At least one of the coupling body and the ring is configured so that the inboard seal seals and connects after the main seal seals and connects to the pipe. An axisymmetrical outboard seal is formed on the inside surface of the coupling body axially spaced from the main seal that connects to the pipe when the ring is installed on the coupling body. At least one of the coupling body and the ring is further configured so that the outboard seal seals and mechanically connects after the inboard seal seals and connects to the pipe. At least one of the coupling body and the ring is still further configured to apply a restoring load to the main seal to further seal and mechanically connect the main seal to the pipe after the outboard seal seals and connects to the pipe.