Double-Walled Corrugated Pipe Socket Extrusion

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Solution Overview

Problem

Existing methods for producing double-walled corrugated pipes with socket sections require complex pressure control during the molding process, as the expansion of the outer and inner tubes occurs at different times and must be coordinated precisely, making the process intricate and difficult to manage.

Innovation Solution

A two-step method where the outer hose is first formed into a socket shape, and then the inner hose is extruded into the socket, allowing for a simpler pressure control by ensuring no temporal overlap in the sleeve formation, achieved by adjusting the axial distance between the nozzles to exceed the sleeve length, thereby simplifying the pressure control requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the one-step method is used to form both outer and inner hose sockets simultaneously, then production time is reduced, but pressure control complexity increases significantly

Engineering Contradiction:
Improveproduction timeVSAvoidpressure control complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent divides the socket formation process into two distinct steps: first forming the outer hose socket, then forming the inner hose socket. This segmentation separates the pressure control requirements into two simpler, sequential control phases rather than one complex simultaneous control phase, resolving the contradiction between productivity and control complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The outer hose socket is formed in advance before the inner hose socket formation begins. This preliminary action allows the outer socket to be fully established with appropriate pressure control before the inner socket process starts, simplifying the overall pressure coordination by eliminating the need for complex real-time pressure synchronization between both hoses.

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If the axial distance between nozzles is increased to exceed sleeve length, then temporal overlap of sleeve formation is eliminated, but device dimensions increase

Engineering Contradiction:
Improvepressure control simplicityVSAvoidaxial distance between nozzles
Core Design Contradiction:
Device complexityVSLength of moving object

Solution Approach 1:

By increasing the axial distance between nozzles beyond the sleeve length, the patent segments the extrusion process into distinct temporal phases. This ensures the outer hose extrusion completes its socket formation before inner hose extrusion begins, eliminating temporal overlap and simplifying pressure control despite the increased device length.

Inventive Principle:
Principle #1Segmentation

3Manufacturing precision

If precise pressure coordination is implemented for simultaneous hose expansion, then manufacturing precision is maintained, but control system complexity increases

Engineering Contradiction:
Improvesocket formation precisionVSAvoidpressure coordination complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The outer hose socket is formed completely before inner hose socket formation begins. This preliminary completion of outer socket ensures precise dimensional control is achieved in the first phase, and the second phase operates independently with its own simpler pressure control requirements, maintaining manufacturing precision while reducing overall control complexity.

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 approach simplifies the pressure control process, allowing for reliable and straightforward production of double-walled corrugated pipes with socket sections by eliminating the need for complex pressure coordination between the inner and outer tubes during molding.

Implementation Method 1

The endless pipe is manufactured continuously by extruding a double-walled plastic melt tube via an extrusion head of an extrusion device, in that an outer tube is extruded from a first nozzle and an inner tube is extruded concentrically into the outer tube via a downstream second nozzle of the extrusion head.

Methodology Applied
Scientific EffectExtrusion: Extrusion

Implementation Method 2

The corrugations and sleeve sections are formed in a corrugator downstream of the extrusion head, i. H. in its mold channel, which has successive corrugated and cylindrical or slightly conical mold surfaces due to rotating pairs of mold jaws.

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

When shaping the outer tube and the inner tube in the shaping channel of the corrugator

Methodology Applied
Scientific EffectDeformation: Deformation

Data Source

PatentEP2574444B1Method and device for producing a double-walled thermoplastic corrugated pipe with a pipe sleeve
Publication Date: 2017.12.06 UNICOR
  • EP2574444B1 patent drawingFigure 1
  • EP2574444B1 patent drawingFigure 2
  • EP2574444B1 patent drawingFigure 3

AI summary

The method involves carrying out extrusion of an outer tube (Sa) forming the outer pipe of the double-walled pipe and an inner tube (Si) forming the inner pipe of the double-walled pipe in a shaped channel (10). The outer tube is extruded into the sleeve shape surface to shape the sleeve section and is brought in contact with the sleeve shape surface. The inner tube is extruded into the outer tube that is already in contact. An independent claim is included for a device for producing an endless double-walled pipe having corrugated pipe sections and connecting sleeve sections.