Foamed PPS Tubular Assembly for Fiberglass-Free Steam Hose Insulation

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Solution Overview

Problem

Existing steam hose manufacturing processes are inefficient and pose safety risks due to the use of fiberglass, which requires special protective equipment, increases labor costs, and is affected by moisture, leading to corrosion and reduced thermal performance.

Innovation Solution

A polyarylene sulfide (PAS) foam layer with reduced density and thermal conductivity is used to circumscribe a hollow inner tube, eliminating the need for fiberglass and enabling a single continuous processing step, thus improving safety, efficiency, and thermal performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If fiberglass or woven insulation is used in steam hose construction, then thermal insulation performance is achieved, but worker safety is compromised due to glass fiber exposure risks

Engineering Contradiction:
Improvethermal insulation performanceVSAvoidglass fiber exposure risk
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent changes the material parameter from fiberglass to foamed polyphenylene sulfide, which maintains thermal insulation properties while eliminating glass fiber exposure risks. The foam structure provides equivalent thermal performance without the harmful crystalline silica content and glass fiber shards that pose safety risks to workers.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses foamed polyphenylene sulfide as a composite material that combines thermal insulation capabilities with safety benefits. This foam material integrates the insulating function while removing the harmful glass fiber components, creating a safer alternative that protects workers from exposure risks.

Inventive Principle:
Principle #40Composite materials

2Temperature

If fiberglass tape is used for insulation, then thermal performance is maintained, but manufacturing efficiency decreases due to discontinuous batch processing requirements

Engineering Contradiction:
Improvethermal performanceVSAvoidmanufacturing efficiency
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The patent enables continuous manufacturing by using foamed polyphenylene sulfide that can be extruded in a single continuous operation. This eliminates the need to stop and change fiberglass or polyimide tape reels, allowing the extrusion process to run continuously without interruptions, thereby improving manufacturing efficiency and productivity.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent extracts the polyimide tape layer from the construction, eliminating the need for separate tape wrapping and jacket extrusion steps. This simplification allows the insulation and protective jacket to be formed in a single continuous extrusion process, removing the bottleneck that required discontinuous batch processing.

Inventive Principle:
Principle #2Taking out (Extraction)

3Temperature

If fiberglass tape is used in steam hose construction, then insulation function is provided, but operational reliability decreases due to moisture sensitivity and chlorine release

Engineering Contradiction:
Improveinsulation functionVSAvoidmoisture resistance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent changes the material composition from fiberglass to foamed polyphenylene sulfide, which inherently resists moisture and does not release chlorine. This material substitution maintains thermal insulation functionality while improving reliability by eliminating moisture sensitivity and corrosion risks associated with fiberglass and polyimide tape.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If polymeric jacket is added to protect fiberglass tape, then protection function is achieved, but handling difficulty increases due to increased weight

Engineering Contradiction:
Improveprotection functionVSAvoidhandling ease
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent uses foamed polyphenylene sulfide as a lightweight composite material that provides both protection and insulation functions. The foam structure delivers adequate mechanical protection while being significantly lighter than solid polymeric jackets, improving handling ease without sacrificing protective functionality.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent employs a foamed (porous) polyphenylene sulfide material that reduces weight while maintaining protective and insulating properties. The cellular foam structure provides sufficient protection against mechanical damage and environmental factors while being lighter than solid polymer alternatives, making the hose easier to handle and install.

Inventive Principle:
Principle #31Porous 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 PAS foam layer provides enhanced thermal performance, reduced weight, improved safety by eliminating glass fibers, and increased productivity through continuous processing, while also reducing manufacturing and supply chain costs.

Implementation Method 1

a foamed thermal effusivity that is foamed from a mixture of an un-foamed polyphenylene sulfide polymer material... the foamed thermal effusivity is less than about 50% of the un-foamed thermal effusivity

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

a tubular second member surrounding the outer surface of the first member, the second member comprising a foamed polyphenylene sulfide polymer material

Methodology Applied
Scientific EffectFoam structure: Foam

Data Source

PatentEP3934906B1Tubular assembly comprising low density, low thermal conductivity low thermal effusivity polyphenylene sulfide foam
Publication Date: 2025.05.07 PARKER HANNIFIN CORP
  • EP3934906B1 patent drawingFigure 1~3
  • EP3934906B1 patent drawingFigure 4~5
  • EP3934906B1 patent drawingFigure 6~8

AI summary

A polyarylene sulfide (PAS) foam layer that circumscribes a hollow inner tube and may have a 50% or greater density reduction relative to the density of an un-foamed PAS polymer material and/or a 50% or greater thermal conductivity reduction relative to the thermal conductivity of an un-foamed PAS polymer material and/or 50% or greater thermal effusivity reduction relative to the thermal effusivity of an un-foamed PAS polymer material. The PAS foam layer may have a low density (e.g., less than 0.67 g/cc) and/or a low thermal conductivity (e.g., anywhere from 0.017 W/(m-K) to 0.145 W/(m-K)) and/or a low thermal effusivity (e.g., less than 316 Ws1/2/m2/K, optionally anywhere from 38 Ws1/2/m2/K to 316 Ws1/2/m2/K) even at high temperatures (e.g., above 400 degrees Fahrenheit (°F) (about 204 degrees Celsius (°C)). Such a PAS foam layer may have characteristics appropriate for use as part of a steam hose.