Subsea Compressor Collection Chamber for Liquid Management

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Solution Overview

Problem

Current submersible compressor units for natural gas extraction from seabed fields face issues such as accidental seawater ingress damaging mechanical components, increased mechanical complexity and cost due to internal separators, and high design and installation challenges related to shaft length and bearing placement.

Innovation Solution

A compact compressor unit with a vertical configuration and a pressurized sealed housing containing a multistage centrifugal compressor and an electric motor, featuring a collection chamber to manage liquid during installation and a balancing system to reduce axial thrust, eliminating the need for external seals and minimizing mechanical complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the valve on the compressor unit is opened before the valve on the separator machine during installation, then the installation process can be simplified, but seawater accidentally enters the compressor unit and damages mechanical components

Engineering Contradiction:
Improveinstallation operationVSAvoidprotection from seawater ingress
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-configuring the compressor unit with a collection chamber that is already prepared to receive and contain seawater during installation. This allows the unit valve to be opened first without risk, as any accidentally entering seawater is automatically directed into the collection chamber rather than damaging the compressor mechanics.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The collection chamber acts as an intermediary element between the unit inlet and the compressor mechanical components. It intercepts and contains seawater that might accidentally enter during installation, preventing direct contact with and damage to the compressor bearings and other mechanical parts.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If a separator is installed inside the compressor unit housing, then liquid can be separated from gas, but the mechanical complexity and cost increase

Engineering Contradiction:
Improveliquid-gas separation capabilityVSAvoidmechanical complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the liquid separation function from the main compressor housing by providing a separate, dedicated collection chamber. This chamber is specifically designed for liquid collection and can be emptied independently, allowing the compressor unit to handle liquid-containing fluids without requiring an internal separator that would complicate the main compressor structure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the compressor unit into functionally distinct zones: the compression chamber for gas compression and the collection chamber for liquid accumulation. This segmentation allows each component to be optimized for its specific function while maintaining overall system simplicity and reducing mechanical complexity.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the lower mechanical bearing is placed on the inferior baseplate of the housing, then the bearing is protected from water contact, but a high sealing case is required increasing installation and design cost

Engineering Contradiction:
Improveprotection from water contactVSAvoidsealing case complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the spatial arrangement by positioning the collection chamber and its outlet at the lowest point of the housing, creating a gravity-driven liquid collection system. This dimensional arrangement allows liquid to naturally accumulate and be discharged without requiring complex sealing mechanisms around the bearings, as the bearing protection is achieved through gravitational drainage rather than sealing barriers.

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

4Reliability

If the shaft is made longer to place the bearing on the baseplate, then the bearing can be positioned for protection, but the design cost increases significantly

Engineering Contradiction:
Improveprotection from water contactVSAvoiddesign cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent converts the potentially harmful effect of liquid presence into a beneficial drainage system. By designing the collection chamber with outlets at the lowest points and utilizing gravity, the system automatically directs liquid away from the bearings without requiring longer shafts or additional protective structures, thereby reducing manufacturing costs while maintaining reliability.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 solution enhances the installation and operational reliability of compressor units by preventing liquid ingress and reducing mechanical complexity, enabling cost-effective and efficient natural gas extraction with reduced maintenance needs for long-term subsea operations.

Implementation Method 1

the collection chamber is configured to collect completely the liquid possibly entered inside said housing during a submerged installation phase thereof

Methodology Applied
Scientific EffectGravity: Gravitation

Implementation Method 2

a multistage centrifugal compressor and an electric motor

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2507516B1Compressor unit and method to process a working fluid
Publication Date: 2021.08.25 NUOVO PIGNONE TECH - SRL
  • EP2507516B1 patent drawingFigure 1~3
  • EP2507516B1 patent drawingFigure 4~5

AI summary

A compressor unit for processing a working fluid comprising a compressor (3) inside a housing (7) to compress the working fluid, wherein a collection chamber (19) is fluidly coupled with a working fluid inlet (71) of said housing (7).