Subsea Fluid Storage Bladder Collapse via Rotatable Piston

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Solution Overview

Problem

Existing subsea fluid storage systems face challenges in maintaining a predictable and repeatable volume, often experiencing unwanted over- or under-pressurization due to the difficulty in controlling the fluid storage effectively.

Innovation Solution

A subsea fluid storage system comprising a pressure-balanced reservoir with a soft, collapsible bladder and a rotatable piston that allows for predictable and repeatable collapse, using a piston rotator and guide sleeve or helical tubes with rollers to manage fluid pressure and prevent binding, along with valves and sensors for leak detection and pressure regulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a soft bladder is used for fluid storage, then the system can be compact and flexible, but the volume becomes unpredictable and difficult to control

Engineering Contradiction:
Improvefluid storage volumeVSAvoidvolume predictability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent applies parameter changes by using a rotatable piston that changes the geometric parameters of the bladder (length, diameter, volume) through rotation. The piston's rotation transforms the bladder from an extended state to a collapsed state in a controlled, predictable manner, converting an unpredictable soft volume into a controllable parameter-based system.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback through sensors that detect the piston position and bladder state, providing information back to the control system. This feedback mechanism ensures predictable volume control by monitoring and adjusting the piston rotation to achieve the desired bladder collapse and fluid discharge.

Inventive Principle:
Principle #23Feedback

2Quantity of substance

If the bladder collapses completely to empty fluid, then fluid removal is complete, but the bladder may bind against the reservoir wall

Engineering Contradiction:
Improvefluid removal completenessVSAvoidbladder collapse smoothness
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The patent resolves the binding problem by adding rotational motion as a new dimension to the piston movement. Instead of simple linear collapse, the piston rotates while moving, causing the bladder to collapse in a spiral or twisted manner that prevents it from binding against the reservoir wall, enabling complete fluid removal without operational interference.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If pressure is increased to force fluid out, then fluid discharge is faster, but over-pressurization can damage the system

Engineering Contradiction:
Improvefluid discharge rateVSAvoidover-pressurization damage
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system applies self-service through pressure-balanced design where the bladder's own elastic recovery force and the controlled piston rotation work together to discharge fluid without requiring excessive external pressure. The bladder naturally pushes fluid outward as it collapses, and the system regulates this self-generated pressure to prevent over-pressurization damage.

Inventive Principle:
Principle #25Self-service

4Device complexity

If the piston moves linearly to collapse the bladder, then the mechanism is simple, but the bladder binds and fluid removal is incomplete

Engineering Contradiction:
Improvepiston mechanism simplicityVSAvoidfluid removal completeness
Core Design Contradiction:
Device complexityVSQuantity of substance

Solution Approach 1:

The patent transforms the static linear piston movement into a dynamic rotational motion. The rotatable piston introduces rotational dynamics that enable the bladder to collapse without binding, completing fluid removal while maintaining relatively simple mechanical components. The rotation converts a simple linear mechanism into a more effective dynamic system.

Inventive Principle:
Principle #15Dynamics

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 system ensures a stable and controlled fluid storage by maintaining a balance between interior and exterior pressures, preventing damage to the bladder and ensuring complete fluid removal, while also providing protection against over- or under-pressurization and leak detection.

Implementation Method 1

soft bladder (20) disposed within pressure balanced reservoir (10)... rotatable piston (30) configured to rotate axially, twisting soft bladder (20) as rotatable piston (30) travels along a predetermined axis within pressure balanced reservoir (10)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

pressure balanced reservoir (10)... maintaining a balance between an interior and an exterior of soft bladder (20)

Methodology Applied
Scientific EffectPressure balance: Pascal's Law

Data Source

PatentEP3512783B1Subsea fluid storage system, method
Publication Date: 2021.12.01 OCEANEERING INTERNATIONAL INC
  • EP3512783B1 patent drawingFigure 1
  • EP3512783B1 patent drawingFigure 2
  • EP3512783B1 patent drawingFigure 3~4

AI summary

Using a subsea fluid storage system 1 comprising a soft bladder (20) disposed within a pressure balanced reservoir (10), a rotatable piston (30) disposed at least partially within the pressure balanced reservoir where a top of the soft bladder is in communication with the rotatable piston, and a piston rotator (50) operative to rotate and twist the rotatable piston as the rotatable piston travels along a predetermined axis within the pressure balanced reservoir, a predictable and repeatable collapse of the soft bladder may be obtained by allowing the rotating piston (30) to cooperatively travel about the piston rotator (50) to twist the soft bladder (20) as the rotating piston moves along the predetermined axis in such a manner as to collapse the bladder inward, thereby emptying the bladder of fluid within the bladder. The rotation of the piston pulls the soft bladder away from an interior of the pressure balanced reservoir, thereby preventing binding or pinching of the bladder with respect to the interior of the pressure balanced reservoir. In configurations, fluid is allowed to enter the pressure balanced reservoir via a valve (54) until a balance is achieved between an interior and an exterior of the pressure balanced reservoir.