Underwater Cutting Head With Cryogenic Jet and Water Shield

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Solution Overview

Problem

Existing methods for cutting underwater offshore steel structures, such as diamond wire cutting and abrasive water jetting, are inefficient and require significant time and resources, making them economically unviable for large-scale applications.

Innovation Solution

A system and method that combines abrasive water jetting with cryogenic assistance, using a cutting head with an abrasive water jetting nozzle and a cryogenic nozzle in fixed spaced relation, and a water repelling shield to maintain arid conditions and prevent temperature increases during the cutting process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If abrasive water jetting is used to cut underwater steel structures, then the cutting process can be performed, but the surrounding water prevents effective heat transfer and reduces cutting speed

Engineering Contradiction:

Improvecutting speedVSAvoidsteel temperature

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The patent introduces an air envelope (inert environment) surrounding the steel structure in the cutting zone. This air envelope acts as a thermal insulator, preventing the surrounding water from rapidly heating the steel surface. By maintaining lower steel temperatures, the steel remains more brittle and responsive to water jet cutting, thereby improving cutting speed and productivity.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Productivity

If cryogenic assistance is used to reduce steel temperature and make it brittle, then cutting effectiveness is enhanced, but the surrounding water rapidly heats the steel, counteracting the cryogenic effect

Engineering Contradiction:

Improvecutting effectivenessVSAvoidsteel temperature stability

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The air envelope serves as a thermal barrier between the cryogenic treatment zone and the surrounding water. This inert environment preserves the low temperature state of the steel longer, allowing the cryogenic assistance to be effective without immediate counteraction from water heating.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The air envelope acts as an intermediary layer between the cryogenic nozzle/steel interface and the surrounding water. It mediates the thermal interaction by providing insulation, allowing cryogenic treatment to occur effectively while preventing direct thermal exchange with the water.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If conventional cutting methods are used, then cutting can be performed, but significant time is required (six to eight hours for abrasive water jetting)

Engineering Contradiction:

Improvecutting capabilityVSAvoidcutting time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent changes the physical state parameters of the steel by applying cryogenic treatment, reducing its temperature below the ductile-brittle transition point. This parameter change makes the steel more brittle and easier to cut with the water jet, dramatically reducing cutting time from six to eight hours to a much shorter duration.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent utilizes the phase transition or state change of steel from ductile to brittle by cooling it below its ductile-brittle transition temperature. This phase transition in mechanical properties enables faster and more effective cutting with the water jet, resolving the time loss issue.

Inventive Principle:

Principle #36Phase transitions

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 combination of abrasive water jetting and cryogenic assistance significantly reduces the time required to cut underwater steel structures by making the steel brittle, thus enhancing the effectiveness of the water jet and allowing for faster cutting processes.

Implementation Method 1

using cryogenic assistance to the water jetting by reducing the metal temperature to below the ductile-brittle transition

Methodology Applied

Scientific EffectCryogenic cooling: Cryogenics

Implementation Method 2

reducing the metal temperature to below the ductile-brittle transition. By making the steel brittle, its ability to absorb energy is reduced

Methodology Applied

Scientific EffectDuctile-brittle transition:

Implementation Method 3

by introducing an air envelope, the surrounding water is prevented from raising the temperature of the steel, through efficient heat transfer, before the water jet can act

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 4

cutting said cutting surface using the abrasive water jet emanating from said abrasive water jetting nozzle

Methodology Applied

Scientific EffectAbrasion: Abrasion

Data Source

PatentUS12220787B2System and method for cutting of offshore structures

Publication Date: 2025.02.11 PETROLIAM NASIONAL BHD

AI summary

A system for cutting an underwater structure, the system comprising: a cutting head, said cutting head comprising: an abrasive water jetting nozzle; a cryogenic nozzle; said abrasive water jetting nozzle and cryogenic nozzle mounted in fixed spaced relation; said cutting head arranged to position tips of the nozzles proximate to a cutting surface, and arranged to form a cutting zone defined by the nozzle tips and cutting surface; wherein a water repelling shield is located about said cutting zone and arranged to hinder water entering said cutting zone.