Sealed Thermoplastic Tank Wall With Single-Stage Winding

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The existing manufacturing processes for waterproof tanks, particularly those without internal liners, are time-consuming and not suitable for large-scale industrial deployment due to the lengthy winding process of thermoplastic materials around a mandrel.

Innovation Solution

A process that forms a waterproof wall in a single winding stage using a fiber-reinforced thermoplastic material, where a knitting envelope made of colmatable thermoplastic material wires is first applied to the mandrel, and then successive sections of a thermoplastic material strip are wound around this envelope to form a monolithic waterproof wall.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a narrow thermoplastic coating strip is wound by multiple turns around the template to form the sealed inner shell, then the gas-tightness is achieved, but the manufacturing time increases significantly

Engineering Contradiction:
Improvegas-tightnessVSAvoidmanufacturing time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent divides the sealing function into two distinct components: an internal liner made of thermoplastic material that provides the gas-tight barrier, and an external reinforcement structure made of fiber-reinforced thermoplastic material that provides mechanical strength. This segmentation allows each component to be optimized independently, with the internal liner focusing on gas-tightness and the external structure on strength, thereby reducing the overall manufacturing time while maintaining reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The internal liner is manufactured separately and in advance using rotational molding or extrusion blow molding, which are much faster processes than winding. This preliminary action allows the gas-tight component to be ready before the external reinforcement structure is applied, eliminating the time-consuming multiple winding turns and significantly reducing total manufacturing time while preserving gas-tightness.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the internal liner is made of metal or polymer, then the gas-tightness is ensured, but the tank mass increases

Engineering Contradiction:
Improvegas-tightnessVSAvoidtank mass
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent changes the material parameter of the internal liner from traditional metal or heavy polymer to a lightweight thermoplastic material. This parameter change maintains the gas-tightness function while significantly reducing the mass of the tank. The thermoplastic material is specifically selected to provide adequate barrier properties against gas permeation while being much lighter than metallic alternatives.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite structure where the internal liner is made of thermoplastic material and the external reinforcement structure is made of fiber-reinforced thermoplastic material. This composite approach allows the tank to achieve both gas-tightness and mechanical strength while minimizing mass, as the fiber reinforcement provides structural support that would otherwise require heavier materials, and the thermoplastic liner provides lightweight gas barrier properties.

Inventive Principle:
Principle #40Composite materials

3Weight of moving object

If a thermoplastic internal liner is used instead of metal liner, then the tank mass is reduced, but the manufacturing complexity increases due to the winding process

Engineering Contradiction:
Improvetank massVSAvoidmanufacturing process complexity
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The patent segments the manufacturing process into two independent stages: first, manufacturing the internal liner using conventional rotational molding or extrusion blow molding; second, applying the external reinforcement structure using fiber winding. This segmentation simplifies each individual process, allowing the internal liner to be produced using well-established, less complex processes, while the external structure handles the reinforcement requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The internal liner is manufactured in advance using simpler, more established processes like rotational molding or extrusion blow molding, which are less complex than the winding process. This preliminary action reduces the overall manufacturing complexity by separating the gas-tight component production from the reinforcement structure application, allowing each to be optimized with appropriate manufacturing techniques.

Inventive Principle:
Principle #10Preliminary action

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

This process significantly reduces the manufacturing time of waterproof tanks by eliminating the need for multiple winding stages, resulting in a faster, more efficient production method that maintains the mechanical resistance and gas barrier properties of the tank.

Implementation Method 1

the material of the wound liner strip being the fiber-reinforced thermoplastic material. The resulting sealed wall of the sealed tank thus comprises two components (the inner shell, the outer shell)

Methodology Applied
Scientific EffectHeat fusion: Heating

Implementation Method 2

Exerting a pressure chosen to tighten each section of the first strip wound against the casing, forming the first layer of first strip, and to clamp the sections covering the first layer of first strip to form the other superimposed layers of first strip

Methodology Applied
Scientific EffectPressure application: Compression

Implementation Method 3

Exercising a temperature chosen to fuse the thermoplastic material of each section of the first layer of first strip with the underlying wires of the casing, and to fuse the sections of the successive layers of first strip

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 4

the winding speed is constrained by the stretching and pressure to be applied to the coating strip so that the first layer is tightly clamped on the template and the successive layers are clamped together. This helps avoid air bubbles between each coil and layer during the heating stage

Methodology Applied
Scientific EffectMechanical pressure: Compression

Data Source

PatentEP4552817A1Method for manufacturing a sealed tank for containing a gas and/or a fluid
Publication Date: 2025.05.14 LAIR LIQUIDE SA POUR LETUDE & LEXPLOITATION DES PROCEDES GEORGES CLAUDE
  • EP4552817A1 patent drawingFigure 1~2
  • EP4552817A1 patent drawingFigure 3~4
  • EP4552817A1 patent drawingFigure 5~6

AI summary

One aspect of the invention relates to a method for manufacturing a sealed tank for containing a gas and/or a liquid, comprising a step of forming a sealed wall of the tank, comprising the following substeps: - Forming a casing by applying at least one knit covering the external surface of the mandrel, the knit comprising knitted yarns of a heat-sealing thermoplastic material, - Filamentary winding, around the casing, of successive sections of a first strip comprising a heat-sealing thermoplastic material reinforced with fibers, so as to fuse the successive wound sections of the first strip, - Cooling the casing and the first strip to form the sealed wall in a single material.