Annular Seal Corner Reinforcement for Extrusion and Fretting Damage
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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
The implementation of a double reinforcing anti-extrusion system within the corners of the sealing elements, comprising a first square or rectangular garter spring and a second garter spring received inside the first, which can also be rectangular, circular, or oval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a garter spring is used to bridge pressure in sealing elements, then pressure bridging capability is improved, but extrusion/fretting damage occurs at corners leading to material loss
Solution Approach 1:
The patent applies nesting by placing a second garter spring inside the first garter spring at the corners of the seal body. This nested configuration allows the inner spring to provide additional support and protection to the unreinforced elastomer material, preventing extrusion damage while maintaining the pressure bridging function of the outer spring.
Solution Approach 2:
The patent applies local quality by reinforcing only the vulnerable corner areas where extrusion damage occurs, rather than strengthening the entire seal body. The garter springs are specifically positioned at the corners to provide localized protection to the unreinforced elastomer material, maintaining overall seal performance while preventing material loss at critical points.
2Reliability
If garter springs are used to bridge pressure, then sealing performance is improved, but the unreinforced elastomer material separates from the spring during pressure cycles
Solution Approach 1:
The nested spring configuration ensures that the inner spring remains in contact with the elastomer material during pressure cycles, providing continuous reinforcement and preventing separation. The concentric arrangement of the two springs creates a more stable structural interface with the seal body compared to a single spring.
Solution Approach 2:
The patent specifies that the second garter spring can be round, oval, or circular in cross-section, while the first spring is square or rectangular. This combination of shapes creates complementary geometric interfaces that improve contact and adhesion between the springs and the elastomer material, reducing separation during cyclic loading.
3Strength
If corner reinforcement is added to prevent extrusion, then extrusion resistance is improved, but device complexity increases
Solution Approach 1:
The reinforcement is applied locally only at the corner areas where extrusion damage occurs, rather than throughout the entire seal body. This targeted approach provides necessary extrusion resistance at critical points while minimizing the addition of complex structural elements.
Solution Approach 2:
The nested spring design consolidates two reinforcement elements into a compact corner configuration. Rather than adding separate external reinforcement features, the inner spring is housed within the outer spring, creating a space-efficient solution that provides enhanced extrusion resistance without significantly increasing overall device complexity.
Data Source
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.