Composite Subsea Compressor Casing for Lower Weight Handling

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Solution Overview

Problem

The existing subsea motorcompressor casings made of metal are heavy, leading to high handling costs and reduced reliability due to the need for large vessels and prolonged intervention times, especially in offshore applications.

Innovation Solution

A dual-layer casing design comprising an inner layer of corrosion-resistant material, such as nickel base alloy, and an outer layer of lightweight composite material, like PEEK reinforced with continuous carbon fibers, to reduce weight and enhance handling capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the casing is made of metal to ensure structural integrity and corrosion resistance, then the strength and corrosion resistance are improved, but the weight increases significantly

Engineering Contradiction:
Improvestructural integrityVSAvoidcasing weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The casing employs a composite structure consisting of an inner metal layer providing corrosion resistance and structural integrity, and an outer composite material layer reducing overall weight. This composite approach allows the casing to maintain strength while significantly reducing weight compared to traditional full-metal construction.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The casing applies different material properties to different regions - the inner layer uses metal material specifically where corrosion resistance and structural strength are critical, while the outer layer uses lighter composite material where weight reduction is prioritized. This localized material selection optimizes the balance between strength and weight.

Inventive Principle:
Principle #3Local quality

2Reliability

If the casing is made of metal to ensure corrosion resistance, then the reliability is improved, but the handling capability deteriorates due to heavy weight

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidhandling capability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The composite casing structure maintains corrosion resistance through the inner metal layer while the outer composite layer reduces weight to improve handling capability. This allows the casing to be both reliable in corrosive environments and easier to handle during installation and maintenance operations.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the material composition parameters of the casing from 100% metal to a composite structure, fundamentally altering the weight-to-strength ratio and enabling both corrosion resistance and improved handling characteristics.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If a heavy load vessel is used to handle the motorcompressor to ensure safe handling, then the handling safety is improved, but the intervention time increases

Engineering Contradiction:
Improvehandling safetyVSAvoidintervention time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

By reducing the casing weight through composite materials, the motorcompressor can be handled by lighter vessels with smaller lifting capacities, enabling faster deployment and retrieval operations while maintaining safety through proper engineering of the lighter handling system.

Inventive Principle:
Principle #40Composite materials

4Strength

If the casing is made of metal to ensure durability, then the structural integrity is improved, but the handling cost increases

Engineering Contradiction:
Improvestructural integrityVSAvoidhandling cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The composite casing structure reduces weight while maintaining structural integrity, directly lowering the lifting capacity requirements of handling vessels and reducing associated operational costs for transportation, installation, and maintenance operations.

Inventive Principle:
Principle #40Composite materials

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 dual-layer casing design significantly reduces the weight and simplifies handling and servicing operations, lowering downtime and associated costs while maintaining structural integrity.

Implementation Method 1

The main body also comprises an outer layer applied over the inner layer and made of a composite material

Methodology Applied
Scientific EffectComposite materials: Composite Materials

Implementation Method 2

The inner layer is made of corrosion and/or erosion resistant material

Methodology Applied
Scientific EffectCorrosion resistance:

Data Source

PatentEP3311031B1Casing for a turbomachine
Publication Date: 2026.02.25 NUOVO PIGNONE TECH SRL
  • EP3311031B1 patent drawingFigure 1~2
  • EP3311031B1 patent drawingFigure 2a
  • EP3311031B1 patent drawingFigure 2b

AI summary

A casing (1) for a subsea compressor comprises a main body (2) having a central axis (A); a plurality of interconnection flanges (4) attached to the main body (2); wherein the main body (2) comprises an inner layer (5) made of corrosion resistant material; an outer layer (6) applied over the inner layer (5) and made of a composite material; wherein the outer layer (6) extends along the entire length of said main body (2).