Dynamic Seal Structure With Low-Friction Ring for High-Pressure Wear
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Solution Overview
Problem
Dynamic sealing devices in offshore applications face challenges with leakage, friction, and premature wear due to rotational movements and high pressures, particularly in FPSO units where existing materials like PTFE and PEEK struggle to maintain effective sealing and mechanical integrity.
Innovation Solution
A radial sealing device is designed with a seal made from polyetheretherketone (PEEK) and an anti-friction ring made from materials like polytetrafluoroethylene (PTFE) or equivalent fluoro-polymers, where the ring has a lower coefficient of friction than the seal, securely connected to optimize sliding and reduce wear, and a pre-stressing spring for enhanced sealing and pressure resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the seal is made from PTFE or fluoro-polymer materials to reduce friction, then the coefficient of friction is reduced, but the resistance to extrusion and mechanical integrity under high pressure deteriorates
Solution Approach 1:
The seal is constructed as a composite structure combining PTFE or fluoro-polymer materials with reinforcement elements (such as braided wires, meshes, or fabric layers) to simultaneously achieve low friction coefficients and high extrusion resistance. The composite structure allows the polymer material to provide lubrication and friction reduction while the reinforcement elements provide mechanical strength and resistance to extrusion under high pressure conditions.
2Strength
If the anti-extrusion ring is made from harder material than the seal to prevent extrusion, then extrusion resistance is improved, but the friction and wear on the seal lips increases
Solution Approach 1:
The sealing system employs different material properties at different locations: the anti-extrusion ring made from harder material (such as PEEK or metal) provides extrusion resistance at the extrusion-prone areas, while the seal lips made from PTFE or fluoro-polymer materials provide low friction and wear resistance at the contact surfaces. This spatial differentiation of material properties allows each component to optimize its function without compromising the other.
3Stability of the object's composition
If the seal body is made solid to provide mechanical integrity and pressure resistance, then structural stability is improved, but the flexibility and friction resistance deteriorates
Solution Approach 1:
The seal body is constructed as a composite structure combining solid reinforcement elements (such as metal or polymer braids, meshes, or fabric layers) with flexible PTFE or fluoro-polymer material. The solid reinforcement provides geometric stability and pressure resistance, while the flexible polymer material maintains suppleness, flexibility, and low friction characteristics. This composite construction allows the seal body to simultaneously achieve structural integrity and friction resistance.
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 solution provides improved resistance to friction and extrusion, extending the service life of the sealing device by minimizing wear and optimizing friction torque, while maintaining effective sealing under high pressures and temperatures.
Implementation Method 1
a pre-stressing spring disposed between the lips to return them to a spread position in which they provide a sealing function
Implementation Method 2
the first coefficient of friction of the first predetermined material forming the seal is greater than the second coefficient of friction of the second predetermined material forming the ring
Data Source
AI summary
Disclosed is a dynamic sealing device configured to provide sealing between at least a first part and at least a second part having a relative rotational movement in relation to the first part. The device includes a seal provided with a first lip and with a second lip extending from a body portion, the first lip facing the second lip, the seal being formed from a first predetermined material having a first coefficient of friction, and a ring formed from a second predetermined material different from the first predetermined material and having a second coefficient of friction different from the first coefficient of friction. The ring is securely connected with the seal at the location of the body portion and the first coefficient of friction of the first predetermined material forming the seal is greater than the second coefficient of friction of the second predetermined material forming the ring.