Insulated Conduit Pipe With HFO Foam and Selective Gas Barrier

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Solution Overview

Problem

Thermally insulated pipe systems face issues with gas diffusion leading to increased thermal conductivity and potential damage due to water vapor accumulation, especially when using plastic medium pipes, as existing barrier layers either suppress gas exchange completely or have inadequate insulation capabilities.

Innovation Solution

Incorporating hydrofluoroolefins (HFOs) as cell gases in the thermal insulation foam, which improves insulation properties and mechanical stability, while also reducing combustibility and preventing bubble formation, combined with a selective barrier layer that allows permeability to water vapor and CO2 while preventing nitrogen and oxygen diffusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metallic barrier layers are used to suppress gas diffusion, then gas exchange is completely prevented, but water vapor diffusion is also completely blocked causing water accumulation in thermal insulation

Engineering Contradiction:

Improvegas diffusion preventionVSAvoidwater vapor accumulation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The barrier layer is designed with spatially varying properties: it provides high gas barrier performance on the outer side while maintaining water vapor permeability on the inner side adjacent to the thermal insulation. This local differentiation allows the barrier to selectively prevent nitrogen and oxygen diffusion while permitting water vapor to escape from the insulation layer.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If polymer barrier layers are used to allow water vapor permeability, then gas diffusion is not completely suppressed, but insulation capability becomes inadequate

Engineering Contradiction:

Improvewater vapor managementVSAvoidgas diffusion prevention

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The barrier layer is constructed as a composite material combining polymer matrix with inorganic barrier particles or layered structures. This composite structure provides both water vapor permeability through the polymer phase and gas barrier properties through the inorganic components, achieving simultaneous protection against nitrogen/oxygen diffusion and water vapor management.

Inventive Principle:

Principle #40Composite materials

3Reliability

If conventional blowing agents are used in foam insulation, then insulation is provided, but thermal conductivity increases over time due to gas diffusion

Engineering Contradiction:

Improveinsulation performanceVSAvoidthermal conductivity increase

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent changes the physical and chemical parameters of the cell gas by using HFO-based blowing agents with specific molecular structures and low thermal conductivity. These parameters are selected to minimize thermal conductivity while maintaining foam stability and resistance to diffusion, thereby preserving insulation performance over time.

Inventive Principle:

Principle #35Parameter changes

4Stability of the object's composition

If barrier layers completely prevent gas exchange, then insulation stability is improved, but water vapor cannot escape causing long-term damage

Engineering Contradiction:

Improvecell gas compositionVSAvoidservice life

Core Design Contradiction:

Stability of the object's compositionVSDuration of action of stationary object

Solution Approach 1:

The barrier layer acts as an intermediary between the external environment and the thermal insulation, selectively mediating gas and vapor transport. It allows water vapor to pass through while blocking nitrogen and oxygen, thereby maintaining cell gas composition stability without preventing necessary water vapor escape, thus extending service life.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 use of HFOs in the cell gases of thermally insulated conduit pipes enhances insulation performance, mechanical stability, and safety, while maintaining effective water vapor management, thereby addressing the challenges of gas diffusion and water vapor accumulation in existing systems.

Implementation Method 1

the cell gas of which contains hydrofluoroolefins (HFOs)... enhances insulation performance

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

a selective barrier layer that allows permeability to water vapor and CO2 while preventing nitrogen and oxygen diffusion

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Data Source

PatentUS11493163B2Thermally insulated medium pipes having HFO-containing cell gas

Publication Date: 2022.11.08 BRUGG ROHR AG HLDG

AI summary

The invention relates to a thermally insulated conduit pipe, comprising at least one medium pipe, at least one thermal insulation arranged around the medium pipe, and at least one outer jacket arranged around the thermal insulation, wherein the outer jacket possibly comprises a barrier made of plastic, and wherein the thermal insulation comprises a foam, the cell gas of which contains at least 10 vol % HFOs. Such conduit pipe has good insulating behavior, good environmental balance, and is easily producible.