Double-Walled Corrugated Pipe Sleeve Formation Pressure Control
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Solution Overview
Problem
The complexity in matching the different pressures acting on the inner and outer tubes during the production of double-walled, corrugated pipes makes precise control challenging, leading to inconsistencies in the sleeve formation process.
Innovation Solution
A method and device where the pressure control sequence for the outer tube involves reducing pressure before extrusion, maintaining pressure above atmospheric during extrusion, and adjusting pressure after completion, while the inner tube's pressure is increased before extrusion, maintained above atmospheric, and reduced afterwards, allowing for independent chronological control of sleeve formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If simultaneous expansion of outer tube and inner tube is used to form corrugated pipe sections, then production efficiency is improved, but pressure control complexity increases
Solution Approach 1:
The forming process is segmented into two distinct phases: first the outer tube is extruded and formed into corrugations, then the inner tube is extruded and formed. This temporal segmentation allows independent pressure control for each tube, reducing control complexity while maintaining continuous production capability.
Solution Approach 2:
The outer tube is completely formed into corrugations before the inner tube extrusion begins. This preliminary action ensures the outer tube structure is stable and ready to receive the inner tube, simplifying the pressure control sequence by eliminating the need for coordinated simultaneous expansion.
2Ease of manufacture
If sequential socket forming of outer hose and inner hose is used, then pressure control simplicity is improved, but forming time increases
Solution Approach 1:
The sequential socket forming is implemented within a continuous extrusion process. While the outer hose socket forms first, the system remains active and ready, allowing the inner hose socket to form immediately afterward without stopping production. This maintains continuous useful action while achieving the pressure control simplicity of sequential forming.
3Manufacturing precision
If complex coordinated pressure control is applied to inner and outer tubes, then forming precision is improved, but control system complexity increases
Solution Approach 1:
Pressure control is segmented into independent sequences for outer tube and inner tube. The outer tube pressure is controlled during its extrusion and corrugation forming, then the inner tube pressure is controlled during its extrusion and socket forming. This segmentation maintains forming precision through dedicated pressure control for each stage without requiring complex coordinated control systems.
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 ensures precise and reliable sleeve formation with optimal wall thickness and smooth inner pipe surfaces, reducing the risk of air pockets and achieving a stable socket formation.
Implementation Method 1
the pressure acting on the inside of the outer hose is reduced shortly before or at the beginning of the extrusion of the outer hose into the socket forming surface
Implementation Method 2
the outer tube is extruded from a first die, and an inner tube is extruded concentrically into the outer tube
Data Source
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AI summary
The invention relates to a method and a device for producing a continuous double-walled pipe, which is made of thermoplastic plastic material and has corrugated pipe segments and sleeve pipe segments. The pipe is produced by extruding an outer tube (Sa), which forms the outer pipe of the double-walled pipe, and an inner tube (Si), which forms the inner pipe of the double-walled pipe, in a molding channel (10), which has at least one segment having a corrugated molding surface and at least one segment having a preferably smooth, cylindrical or slightly conical sleeve molding surface. According to the invention, in order to mold a sleeve segment, the outer tube (Sa) is extruded into the sleeve molding surface and is brought in contact with the sleeve molding surface and the inner tube (Si) is extruded into the outer tube (Sa) already in contact over the entire axial length of the sleeve molding surface and is brought in contact with the inner surface of said outer tube (Sa) already in contact over the entire axial length of the sleeve molding surface. According to the method, the pressure (pa) acting on the inner surface of the outer tube (Sa) is controlled by means of steps a1 to a4 described in more detail, and the pressure (pi) acting on the inner surface of the inner tube (Si) is controlled by means of steps b1 to b3 described in more detail.