Serial Bearing System for Riser Tensioner Side-Load Mitigation

Solution Overview

Problem

Riser tensioner systems in offshore oil platforms are prone to failures due to side-loads from oceanic wave energy, which exceed the load-bearing capabilities of hydraulic or pneumatic cylinders, leading to reduced system lifetime and increased maintenance costs, with existing solutions either increasing size and cost or being economically infeasible.

Innovation Solution

A serial bearing system for riser tensioner systems, comprising a vertical support frame with vertically oriented cylinders and a collar with laterally extending arms, utilizing a radial bearing stack with disc-shaped elastomeric and shim elements, and a spherical bearing stack with spherical sections, providing lateral and cocking compliance while maintaining high axial stiffness to mitigate severe side-loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a more robust cylinder and seal are designed to withstand high side-loads, then the load-bearing capability is improved, but the physical size and manufacturing cost increase

Engineering Contradiction:

Improveload-bearing capabilityVSAvoidphysical size

Core Design Contradiction:

StrengthVSVolume of moving object

Solution Approach 1:

A bearing assembly is introduced as an intermediary component between the riser tensioner system and the cylinder. This bearing assembly absorbs and mitigates severe side-loads through its radial and spherical bearing stacks, protecting the cylinder and seal from excessive lateral forces while maintaining the original cylinder dimensions and avoiding increased physical size.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Strength

If a more robust cylinder and seal are designed to withstand high side-loads, then the load-bearing capability is improved, but the manufacturing cost increases

Engineering Contradiction:

Improveload-bearing capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The bearing assembly serves as a cost-effective intermediary solution that protects the expensive cylinder and seal from side-load damage. Rather than manufacturing more robust and expensive cylinders, the bearing assembly is introduced to absorb lateral forces, significantly reducing the risk of cylinder failure and extending system lifetime without increasing manufacturing costs.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The bearing assembly provides beforehand cushioning by being installed in advance to protect the cylinder from severe side-loads. The radial and spherical bearing stacks are positioned to absorb lateral forces before they can damage the cylinder seal or piston rod, preventing costly maintenance and replacement efforts.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If the cylinder is designed to resist high side-loads, then the system reliability is improved, but the device complexity increases

Engineering Contradiction:

Improvesystem reliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

A bearing assembly is introduced as an intermediary component between the riser tensioner system and the cylinder. This bearing assembly absorbs and mitigates severe side-loads through its radial and spherical bearing stacks, protecting the cylinder and seal from excessive lateral forces while maintaining the original cylinder dimensions and avoiding increased physical size.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If maintenance or replacement efforts are performed on cylinders subjected to high lateral loads, then the cylinder reliability is restored, but the lost time and financial expenses increase

Engineering Contradiction:

Improvecylinder reliabilityVSAvoidmaintenance time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The bearing assembly provides beforehand cushioning by being installed in advance to protect the cylinder from severe side-loads. The radial and spherical bearing stacks are positioned to absorb lateral forces before they can damage the cylinder seal or piston rod, preventing costly maintenance and replacement efforts and reducing downtime.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 serial bearing system effectively reduces severe side-load impacts on cylinder seals and piston rods, enhancing the lifespan of riser tensioner systems while maintaining economical manufacturability and reducing maintenance needs.

Implementation Method 1

a radial bearing stack disposed between the radial bearing mount and the intermediate mount, the radial bearing stack having elastomeric elements and shim elements

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

a spherical bearing stack disposed between the spherical bearing mount and the intermediate mount, the spherical bearing stack having elastomeric elements and shim elements

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentEP3063361B1Improved riser tensioner bearing system

Publication Date: 2020.05.06 LORD CORP

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AI summary

A serial bearing (300) for a riser tensioner system is provided. The serial bearing improves lateral and axial load performance when severe side-loads are transferred to the riser tensioner system.