Double Metal-to-Metal Seal Assembly for Misalignment Tolerance
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Solution Overview
Problem
Existing metal-to-metal seal assemblies in subsea applications are prone to damage during connection due to misalignment, making it difficult to achieve a reliable double seal, especially when a secondary elastomer seal is required, which has limitations in chemical compatibility and temperature range.
Innovation Solution
A seal assembly design featuring a first part with a projecting rib and a second part with a recess of larger cross-sectional area, allowing for relative movement between the parts to accommodate misalignment, thereby enabling a double metal-to-metal seal without damage, even with minor geometrical misalignments between piping elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single metal to metal seal is used, then the seal provides a simple and robust sealing solution, but it has low tolerance with regards to misalignments between connected parts due to the rigidity of the seal
Solution Approach 1:
The seal assembly is divided into two separate metal seal rings (first and second metal seals) positioned at different locations. This segmentation allows each seal to independently accommodate misalignment, with the first seal handling axial misalignment and the second seal handling radial misalignment, thereby resolving the contradiction between seal integrity and tolerance to misalignment.
Solution Approach 2:
The seal assembly incorporates flexible elements including an elastomeric seal and a resilient ring that can deform elastically. These dynamic components allow the rigid metal seals to maintain contact and sealing effectiveness even when misalignment occurs, enabling the system to adapt to dimensional variations while maintaining seal integrity.
2Reliability
If a double seal system is implemented to improve sealing reliability, then the sealing performance is enhanced, but the complexity of the device increases
Solution Approach 1:
The invention merges two different sealing mechanisms (metal-to-metal seals and elastomeric seal) into a single integrated seal assembly. The first and second metal seals work together with the elastomeric seal and resilient ring to provide redundant sealing paths, enhancing reliability while maintaining a compact structure that does not excessively increase device complexity.
Solution Approach 2:
The seal assembly is designed to perform multiple sealing functions simultaneously - the first metal seal provides primary sealing, the second metal seal provides secondary sealing, and the elastomeric seal provides backup sealing. This multi-functionality allows a single assembly to address various sealing requirements without proportionally increasing complexity.
3Reliability
If an elastomer seal is added as a secondary seal, then the sealing capability is improved, but the chemical compatibility and temperature range are limited
Solution Approach 1:
The invention applies different materials with specific properties to different locations within the seal assembly. The metal seals (first and second) are positioned at critical sealing points where high temperature and pressure resistance is required, while the elastomeric seal is positioned where flexibility and conformability are needed. This local differentiation allows each material to perform optimally within its suitable range, resolving the contradiction between sealing capability and material compatibility.
4Reliability
If the seal is made rigid to maintain seal integrity, then the sealing effectiveness is improved, but the seal is prone to damage during make-up of connections due to misalignment
Solution Approach 1:
The elastomeric seal and resilient ring act as cushioning elements that absorb misalignment stresses before they reach the rigid metal seals. These compliant components deform to accommodate dimensional variations and misalignment during connection make-up, protecting the brittle metal seals from damage while maintaining seal integrity throughout the assembly process.
Data Source
AI summary
A seal assembly (1) for a piping connection comprising; a first part (2) having at least one projecting rib (18) extending at least partially along an outer circumference thereof, and a second part (3) arranged to be attached to the first part, the second part being provided with at least one recess (16) on an inner surface thereof, which recess (16) is adapted to receive the projecting rib (18) when the first (2) and second (3) parts are connected, and the recess (16) has a larger cross-section area than the cross-section area occupied by the projecting rib (18) within the recess (16), such that when the first (2) and second (3) parts are connected, they are free to move relative to each other in at least one direction.