Bidirectional Metal Face Seal With Pressure Self-Energizing Teeth

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Solution Overview

Problem

Existing metal face seals in the oil and gas industry require pre-load for sealing and are not self-energizable, limiting their effectiveness under varying pressures and temperatures, and lack bidirectional operation capabilities.

Innovation Solution

A metal face seal with a 'fishbone' shape featuring teeth at acute angles both radially inward and outward, allowing self-energization by internal and external pressures, including hydrostatic pressure, with axisymmetric or non-axisymmetric geometry options for reduced production and assembly costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional metal face seals are used with pre-load dependency, then sealing is maintained under varying pressures, but the seal requires high assembly loads and external pre-loading mechanisms

Engineering Contradiction:
Improvesealing performanceVSAvoidassembly load
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The seal ring is designed to automatically energize itself through its unique geometry. The radially inwardly directed teeth engage with the mating surface and are forced together by fluid pressure differential, eliminating the need for external pre-loading mechanisms. The seal serves its own energization function through the pressure-actuated engagement of its toothed geometry.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The seal utilizes changes in pressure parameters to activate its sealing mechanism. When pressure differential exceeds a threshold, the radially inwardly directed teeth are forced into engagement, automatically transitioning the seal from a non-sealing to a sealing state without requiring external intervention or pre-load adjustment.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If unidirectional sealing geometry is used, then the seal structure is simpler, but the seal cannot operate under bidirectional pressure conditions

Engineering Contradiction:
Improvebidirectional operationVSAvoidseal geometry
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The seal ring features asymmetric tooth geometry with radially inwardly directed teeth on one side and radially outwardly directed teeth on the opposite side. This asymmetric design enables the seal to function in bidirectional pressure conditions, as each set of teeth is optimized for engagement in its respective pressure direction, allowing versatile operation without requiring multiple seals.

Inventive Principle:
Principle #4Asymmetry

3Ease of manufacture

If separation of structural element and sealing element is implemented, then smoother metal alloys can be used and rings can be reused, but the device complexity increases

Engineering Contradiction:
Improvematerial selectionVSAvoidcomponent structure
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The invention merges the structural element and sealing element into a single integrated seal ring component. The unique geometry combines load-bearing structural features with sealing functionality, eliminating the need for separate structural and sealing elements while maintaining the benefits of smoother metal alloys and reusability through proper material selection.

Inventive Principle:
Principle #5Merging (Combining)

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 seal is self-energizable in both directions, providing high resistance to pressure and reducing assembly loads, applicable across diverse engineering fields beyond oil and gas, with cost-effective and efficient sealing performance.

Implementation Method 1

The device used for this kind of sealing uses the principle of plastic deformation of the seal material, requiring high loads to energize and maintain sealing in the working loads of the equipment.

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

the metal face airtight seal of the system, object of the invention, the characteristic of being self-energizable both at internal pressure and at external pressure, coming from the hydrostatic column and from another source of pressure

Methodology Applied
Scientific EffectPressure actuation: Pressure Increase

Data Source

PatentEP3492783B1System comprising bi-directional face metal sealing seal that can be self-powered by pressure
Publication Date: 2024.12.18 FMC TECH DO BRASIL
  • EP3492783B1 patent drawingFigure 1~2
  • EP3492783B1 patent drawingFigure 3~4
  • EP3492783B1 patent drawingFigure 5~6

AI summary

The invention refers to a new metal airtight seal with bidirectional face, self-energizable by pressure, with axisymmetric or non-axisymmetric configuration, comprising teeth guided at acute angles, both towards the center of the ring and outside, radially. This new geometry as proposed grants to the airtight seal (1) the characteristic of being self-energizable by fluid pressure and providing bidirectional sealing, both to the internal pressure and to the external pressure. Furthermore, an element (5) has a course stopper, so to limit the deformation of said metal airtight seal. The elements (4) and (8) grant to the airtight seal high resistance against internal and external pressure, due to the control of radial slacks (6) and (7), respectively.