Air Conditioning Hose Manufacturing via Braid Shrinkage

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Solution Overview

Problem

The existing manufacturing process for air-conditioning hoses is hindered by the slow knitting of reinforcement yarns, which limits the optimal utilization of production facilities and delays the manufacturing of hoses.

Innovation Solution

A method involving the separate production of tubular reinforcement yarn or plastic braid, followed by extrusion of a permeation barrier, wrapping the reinforcement onto the barrier, extrusion of an elastomer layer, and vulcanization, with additional steps for axial compression, diameter reduction, and heating to enhance adhesion, allowing for improved facility utilization and hose production efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the reinforcement yarn is knitted onto the extruded elastomeric inner layer, then the hose structure is formed, but the production facilities cannot be used optimally due to the slow knitting process

Engineering Contradiction:
Improvehose structure formationVSAvoidproduction facility utilization
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The manufacturing process is divided into separate independent steps: the reinforcement yarn or plastic mesh is produced separately on specialized machines, then applied to the extruded permeation barrier in a subsequent step. This segmentation allows different production facilities to work independently and simultaneously, eliminating the bottleneck caused by sequential knitting operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The reinforcement yarn or plastic mesh is prepared and produced in advance on separately optimized machines before being applied to the hose structure. This preliminary action allows the reinforcement component to be ready when needed, preventing idle time for extrusion and vulcanization devices while maintaining optimal production rhythm.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If the tubular reinforcement yarn or plastic braid is pulled onto the permeation barrier, then the reinforcement is applied, but the diameter mismatch may cause creases

Engineering Contradiction:
Improvereinforcement applicationVSAvoidsurface smoothness
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The diameter of the tubular reinforcement yarn or plastic braid is adjusted as a variable parameter during the pulling process. By controlling the reduction in diameter to match the outer diameter of the permeation barrier, the reinforcement can be applied smoothly without creases or wrinkles, ensuring surface quality.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the reinforcement yarn or plastic braid is heated to shrinkage temperature, then the adhesion is improved, but the process time increases

Engineering Contradiction:
Improvereinforcement adhesionVSAvoidheating process time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The reinforcement yarn or plastic mesh undergoes a thermal phase transition when heated to its specific shrinkage temperature. This phase transition causes the material to contract and tighten, creating strong mechanical adhesion to the permeation barrier. The heating step transforms the reinforcement from a loose state to a tightly adhered state, ensuring it remains fixed during subsequent extrusion and vulcanization processes.

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

This method enables faster and more efficient production of air-conditioning hoses by optimizing the use of manufacturing equipment, ensuring better compressive strength and low permeation rates, while allowing for space-saving accommodation and improved adhesion of reinforcement layers.

Implementation Method 1

heating of the drawn-on reinforcement yarn or plastic braid to a shrinkage temperature specific to the reinforcement yarn or plastic braid

Methodology Applied
Scientific EffectThermal shrinkage: Thermal Contraction

Implementation Method 2

vulcanization of the resulting blank to form a finished hose

Methodology Applied
Scientific EffectVulcanization:

Data Source

PatentEP3498449B1Method for manufacturing an air conditioning hose and device for performing the method
Publication Date: 2021.12.08 CONTITECH TECHNO CHEMIE GMBH
  • EP3498449B1 patent drawingFigure 1

AI summary

The invention relates to a manufacturing method and a device for producing a flexible hose with a permeation barrier (2), a pressure-bearing yarn or plastic braid (4), and an elastomer outer layer (7). It aims to create a manufacturing process for better utilization of production facilities.This problem is solved by the manufacturing process comprising at least the following steps: - sliding a separately provided pressure-bearing yarn or plastic braid (4) onto a hollow mandrel (3A) under axial compression, - extrusion of a tubular permeation barrier (2) made of elastomeric material, wherein the permeation barrier (2) is passed through the hollow mandrel (3A) with the braid (4) slid onto the hollow mandrel (3A) and the braid (4) is pulled off the hollow mandrel (3A) and onto the permeation barrier (2), - heating the pulled-on braid (4) to a specific shrinkage temperature while fixing the braid (4) onto the permeation barrier (2), - extrusion of an elastomer outer layer (7) onto the permeation barrier (2) and the braid (4), and - vulcanization to form a finished tube.