Subsea Wellhead Connector Teeth Geometry for Vibration Resistance

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Solution Overview

Problem

Subsea hydraulic connectors face challenges in maintaining a secure and fluid-tight connection under varying loads and orientations, particularly due to issues like Vortex Induced Vibrations (VIV) and uneven stress distribution, which can lead to premature wear and accidental unlocking.

Innovation Solution

A subsea connector design featuring a tubular configuration with multiple segments and altered tooth profiles, including a first and second jaw with teeth that have altered surfaces, allowing for improved engagement and locking mechanisms to distribute stress evenly and resist vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If multiple teeth are used to distribute stress, then stress distribution improves, but wear and accidental unlocking increase due to VIV

Engineering Contradiction:
Improvestress distributionVSAvoidconnection security
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The patent modifies the geometric parameters of the teeth by introducing an altered surface on the leading side, creating an edge point that changes the contact mechanics. This parameter change transforms the contact from surface-to-surface to point-to-surface engagement, reducing the number of active contact points and thereby reducing wear while maintaining stress distribution benefits.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The altered surface on the leading side of the tooth creates an asymmetric geometry where the edge point is positioned differently relative to the axial center compared to traditional symmetric tooth profiles. This asymmetry allows the first tooth to engage the receiving profile at a specific edge point that optimizes both stress distribution and wear resistance.

Inventive Principle:
Principle #4Asymmetry

2Strength

If hydraulic pressure is used to drive connecting segments, then connection strength improves, but complexity of the locking mechanism increases

Engineering Contradiction:
Improveconnection strengthVSAvoidlocking mechanism complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The connector is divided into multiple connecting segments that can move radially independently. Each segment is equipped with its own locking profile and can be actuated by the hydraulic piston to engage with corresponding receiving profiles on the mating components. This segmentation allows the complex locking function to be distributed across multiple simpler, identical modules.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A hydraulic piston is used to actuate the connecting segments radially. The hydraulic pressure provides the force necessary to move the segments from their retracted position to their extended locking position, where they engage with the mating components. This hydraulic actuation mechanism provides strong, reliable locking while keeping the control system relatively simple.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Reliability

If gasket is used to form fluid-tight seal, then sealing effectiveness improves, but preload requirements increase leading to higher contact stresses

Engineering Contradiction:
Improvesealing effectivenessVSAvoidcontact stress
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The connecting segments are designed to engage with the mating components and establish mechanical interlocking before the gasket is compressed. The locking profiles engage first, providing structural support and alignment, which then enables the gasket to be energized with appropriate preload without excessive contact stresses. This preliminary mechanical engagement prepares the connection for effective sealing.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4055248B1Wellhead connecting assembly
Publication Date: 2024.10.16 FMC TECHNOLOGIES INC
  • EP4055248B1 patent drawingFigure 1
  • EP4055248B1 patent drawingFigure 2
  • EP4055248B1 patent drawingFigure 3

AI summary

A connecting assembly for connecting a first body and a second body includes a connector having a plurality of segments and a main piston positioned around at least a portion of the connector. The connector includes: a channel that extends longitudinally through the connector from a first end to a second end; a plurality of teeth formed on an inside of the connector near the first end and near the second end; a first jaw formed of at least one teeth near the first end; and a second jaw formed of at least one teeth near the second end and axially spaced apart from the first jaw. Each of the plurality of teeth has a leading side facing an axial center of the connector, a top side, a contact point at a transition between the leading side and the top side, and a trailing side opposite the leading side. The teeth of the second jaw include: a first tooth axially closer to the axial center of the connector than the remaining teeth of the second jaw and an end tooth axially farther from the axial center of the connector than the remaining teeth of the second jaw.