Nested Garter Spring Seal Structure for Extrusion Resistance

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Solution Overview

Problem

Sealing elements such as packers and S/Fs seals suffer from extrusion/fretting damage at corners where garter springs are used, leading to material loss and reduced performance.

Innovation Solution

A sealing element with a double reinforcing anti-extrusion system, featuring a first square or rectangular garter spring embedded in the seal body's corners, with a second garter spring received inside the first, providing enhanced extrusion resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a single garter spring is used to bridge pressure in sealing elements, then the sealing element can maintain contact pressure, but extrusion/fretting damage occurs at the corner where the spring contacts the seal body

Engineering Contradiction:
Improvecontact pressureVSAvoidextrusion resistance
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent applies nesting by placing a second garter spring inside the first garter spring at the corner of the seal body. This nested configuration allows the springs to work together, with the inner spring providing additional support and preventing extrusion damage while the outer spring maintains contact pressure. The nested structure distributes stresses more effectively and prevents the material loss that occurs with a single spring.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Stability of the object's composition

If garter springs are used to bridge pressure, then sealing contact is maintained, but material loss occurs due to extrusion damage at the spring-seal interface

Engineering Contradiction:
Improvesealing contact stabilityVSAvoidmaterial loss
Core Design Contradiction:
Stability of the object's compositionVSLoss of substance

Solution Approach 1:

The patent applies beforehand cushioning by positioning the second garter spring inside the first spring in advance, creating a protective barrier against extrusion damage before it occurs. This pre-positioned nested spring system cushions the seal body corner from the harmful extrusion forces that would otherwise cause material loss during pressure cycling.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Device complexity

If traditional single-spring garter systems are used, then device complexity is low, but extrusion damage reduces confidence in the sealing solution

Engineering Contradiction:
Improvespring system complexityVSAvoidsealing solution confidence
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The nested dual-spring configuration provides enhanced reliability and confidence in the sealing solution by preventing extrusion damage, while maintaining relatively simple installation and maintenance procedures. The springs are embedded in the corner of the seal body, and their nested arrangement maximizes protective effect within a compact space.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP4556760A1Sealing element with extrusion prevention feature
Publication Date: 2025.05.21 FREUDENBERG FLOW TECH LLC
  • EP4556760A1 patent drawingFigure 1~3
  • EP4556760A1 patent drawingFigure 4~6
  • EP4556760A1 patent drawingFigure 7

AI summary

A sealing element for sealing a gap between a first member and a second member includes an annular seal body having an inner surface, an outer surface and a pair of side surfaces each connected between opposite ends of the inner surface and the outer surface. A first square garter spring embedded within at least one of an inner and an outer corner of the annular seal body.