Cutting Ring Seal Geometry for High-Pressure Tube Connectors
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Solution Overview
Problem
Existing tube connector systems face challenges in achieving a strong, stress-resistant connection while ensuring proper sealing and reducing wear on sealing elements, especially under high-pressure operations.
Innovation Solution
The proposed tube connector system incorporates a cutting ring with a radially extending collar and an elastomeric seal disposed within an annular groove, featuring a transition area angled radially inward to reduce stress concentrations and facilitate radial compression around the tube.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the cutting ring uses a straight cylindrical outer surface, then manufacturing is simple, but stress concentrations occur under high pressure causing cracking
Solution Approach 1:
The cutting ring incorporates a radially inwardly angled transition area (frustoconical shape) between the cylindrical outer surface and the radial surface. This curved/angled transition distributes stress more evenly under high pressure, preventing stress concentrations and cracking that would occur with a straight cylindrical design.
2Reliability
If the annular groove is defined on the radial surface only, then sealing is effective, but the sealing element experiences high wear
Solution Approach 1:
The annular groove is positioned at the transition area where the radial surface meets the cylindrical outer surface, rather than being defined solely on the radial surface. This three-dimensional positioning allows the sealing element to be compressed between the radial surface and the angled transition area, creating effective sealing while distributing wear across both surfaces.
3Ease of manufacture
If the transition area is absent, then manufacturing is easier, but stress concentrations cause cracking under pressure
Solution Approach 1:
The transition area is formed with a radially inwardly angled frustoconical surface that smoothly connects the cylindrical outer surface to the radial surface. This curved transition is manufactured using standard machining operations and eliminates stress concentrations that would cause cracking under high pressure.
4Reliability
If the annular groove is radially undercut, then the sealing element is retained better, but manufacturing precision requirements increase
Solution Approach 1:
The radially inwardly angled transition area naturally creates a retaining effect for the sealing element in the annular groove. The angled surface geometry provides mechanical retention through its shape rather than requiring precise radial undercutting, thereby reducing manufacturing precision requirements while maintaining reliable seal retention.
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 enhances the strength of the cutting ring, reduces stress cracking, ensures proper sealing, minimizes wear on sealing elements, and improves manufacturing efficiencies by allowing robust tooling and easier assembly.
Implementation Method 1
The tube fitting body forms an outer leak path seal with the cutting ring by axially compressing an elastomeric seal
Implementation Method 2
the cutting ring radially compresses around the tube to form a secure coupling
Data Source
AI summary
A connector system includes a fitting body (104) and a union nut (106). A cutting ring (102) is disposed proximate within the fitting body and union nut. The cutting ring includes a first end (136) engaging with the fitting body and having at least one cutting edge, a second end engaging with the union nut, and a radially extending collar (140) disposed between the first end and the second end. The collar having an annular radial surface facing the first end and an annular groove (144) is defined within the radial surface. A cylindrical outer surface having a first diameter is disposed between the radial surface and the first end, and a transition area is defined from the outer surface towards the radial surface. The transition area being angled radially inward such that the transition area has a second diameter that is less than the first diameter. An elastomeric seal (146) is disposed within the annular groove.