High-Pressure Seal Assembly Back-Up Ring Stress Optimization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing dynamic seal assemblies for high-pressure applications, such as those in oilfields and gasfields, suffer from damage like wearing and cracking of back-up rings due to excessive stress, which shortens their lifespan and reduces their effectiveness in maintaining seals under high pressure and temperature conditions.
Innovation Solution
The design incorporates a seal member made of elastomer with axially opposing sides and back-up rings made of high-strength plastic materials, where the ratio of the axial length of the back-up ring's portion to its total length is optimized to ensure that the maximum stress on the back-up ring is below its breaking compressive stress, reducing damage and enhancing support for the seal member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If back-up rings are used to support the seal member in high pressure applications, then the seal assembly can maintain sealing effectiveness under high pressure, but the back-up rings suffer from excessive stress causing wearing and cracking damage
Solution Approach 1:
The patent changes the geometric parameters of the back-up ring by defining a specific axial length ratio (L1/L0) between the portion abutting the seal member and the total length. This parameter optimization ensures that the maximum stress on the back-up ring remains below its breaking compressive stress, thereby preventing wearing and cracking while maintaining sealing effectiveness under high pressure conditions
2Force
If the back-up ring axial length is increased to provide better support for the seal member, then support capability improves, but stress concentration and damage risk increase
Solution Approach 1:
The patent optimizes the axial length parameter of the back-up ring by establishing a specific ratio (L1/L0) between the supporting portion length and total length. This parameter change balances the support capability with stress distribution, ensuring adequate seal member support while keeping maximum stress below the breaking compressive stress threshold
Solution Approach 2:
The patent applies different functional qualities to different portions of the back-up ring. The first portion (length L1) that abuts the seal member is designed with specific dimensions to provide localized support, while the overall length (L0) is optimized to distribute stress. This local quality differentiation allows the back-up ring to provide necessary support without excessive stress concentration
Data Source
AI summary
A seal assembly and an apparatus including the same are provided. The seal assembly may include a seal member with axially opposing sides and one or two back-up rings for substantially supporting at least one side of the seal member. The seal member may be made of elastomer and have an axially extending base with one or two flange portions and a protrusion extending perpendicularly from the base. The back-up ring may be made of a plastic material and a portion of the back-up ring may abut a radially outer surface of the flange portion of the seal member.