Twin-Wall Pipe Overflow Passage Design for Adherence
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Solution Overview
Problem
Existing twin-wall pipe manufacturing methods face challenges in ensuring a sufficiently free cross-section for the overflow passage, leading to potential ventilation issues and adherence problems between the internal and external tubes, especially at the transition portions.
Innovation Solution
Designing the overflow passage and recesses with a radial outer height (b) greater than its width (a) in the circumferential direction, and using partial vacuum to enhance the through-flow, along with distinctively rounded walls and strategically placing additional partial vacuum channels to prevent plastic melt from being squeezed into the overflow passage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the overflow passage cross-section is made smaller to reduce material usage, then manufacturing cost decreases, but ventilation capability deteriorates leading to adherence problems between internal and external tubes
Solution Approach 1:
The patent changes the geometric parameters of the overflow passage, specifically setting the radial outer height (b) to be greater than the width (a) in the circumferential direction. This parameter optimization ensures sufficient ventilation cross-section while minimizing material usage, preventing adherence problems between the internal and external tubes during the molding process.
Solution Approach 2:
The patent applies local quality by creating distinctively rounded walls in the overflow passage rather than uniform sharp edges throughout. This localized rounding at critical areas improves material flow and ventilation characteristics where needed most, maintaining reliability without requiring overall enlargement of the passage.
2Object-affected harmful factors
If the transition portion radial extension is increased to prevent dead spaces, then dirt deposition is reduced, but the risk of internal tube non-adherence increases
Solution Approach 1:
The patent optimizes the geometric parameters of the transition portion, specifically controlling the radial extension and the overflow passage dimensions (a≧b relationship). This parameter optimization allows the transition portion to maintain sufficient radial extension to prevent dead spaces where dirt could deposit, while the controlled overflow passage geometry ensures adequate ventilation to prevent internal tube non-adherence.
Solution Approach 2:
The overflow passage acts as an intermediary element between the transition portion and the adjacent elevation. It provides a controlled ventilation pathway that mediates between the need for radial extension (to prevent dead spaces) and the need for tube adherence (requiring proper venting). The passage allows air and volatiles to escape while maintaining the structural integrity and adherence of the tubes.
3Reliability
If additional partial vacuum channels are added to prevent plastic melt squeezing, then overflow passage blockage is prevented, but device complexity increases
Solution Approach 1:
The patent applies local quality by implementing distinctively rounded walls at specific locations within the overflow passage rather than modifying the entire mold structure. This localized approach prevents plastic melt squeezing and blockage at critical points where it would cause problems, while avoiding the need for complex additional vacuum channels throughout the entire device.
Solution Approach 2:
The patent uses spheroidality by creating distinctively rounded walls in the overflow passage instead of sharp angular features. This curvature prevents plastic melt from adhering to and blocking the passage walls, maintaining reliability without requiring additional complex vacuum channels or mold modifications.
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
Ensures a sufficiently large and free through-flow cross-section for the overflow passage, improving ventilation and adherence between the internal and external tubes, thereby reducing the risk of dead spaces and enhancing the manufacturing process.
Implementation Method 1
corrugating the external tube with elevations and troughs by partial vacuum applied from outside
Implementation Method 2
actuating the internal tube inwardly by gas of a pressure above atmospheric pressure and expanding and pressing the internal tube full face against the expanded area of the external tube
Data Source
AI summary
A twin-wall pipe comprises an internal pipe and an external pipe. The external pipe is corrugated, having elevations and troughs. The twin-wall pipe is further provided with a socket. In a transition portion towards the twin-wall pipe and the socket, provision is made for at least one overflow passage which interconnects the clearance between the external pipe and internal pipe in the vicinity of the transition portion and an adjacent elevation. a≧b refers to the radial height b of the overflow passage relative to its width a in the circumferential direction.