Connection Element Piercing Thermoplastic Fuel Tank Wall
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Solution Overview
Problem
Existing processes for producing thermoplastic fuel tanks by extrusion blow molding face challenges in integrating connection elements without creating leakage paths, as the plastic materials used tend to swell and are not diffusion-tight, making it difficult to weld compatible components.
Innovation Solution
A process where a connection element with a penetration tip is used to pierce the container wall during shaping, allowing the element to pass through and remain as a lost shaping punch, minimizing wall deformation and using a die or insert to facilitate seamless integration of hoses or valves, ensuring minimal leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If connection elements are integrated into thermoplastic fuel tanks by welding, then structural integrity is improved, but leakage paths occur at weld locations due to material swelling and lack of diffusion-tight integrity
Solution Approach 1:
The connection element is divided into multiple functional parts: a penetration tip for piercing the tank wall, a connection body for mechanical connection, and a sealing element. This segmentation allows each part to perform its specific function optimally - the penetration tip creates the opening, while the sealing element prevents leakage at the connection point, avoiding the welding problem entirely.
Solution Approach 2:
A sealing element acts as an intermediary between the connection element and the tank wall. This sealing component fills the gap created by the penetration tip and prevents hydrocarbon leakage, mediating between the need for structural connection and the requirement for leakage prevention without requiring welding.
2Reliability
If complicated two-component structural parts are used for connection elements, then leakage paths are avoided, but device complexity and manufacturing cost increase
Solution Approach 1:
The penetration tip, connection body, and sealing element are merged into a single integrated connection element that can be inserted as one piece. This combining approach achieves the leakage prevention benefits of multi-component designs while maintaining the simplicity of a single-component structure, reducing both device complexity and manufacturing cost.
Solution Approach 2:
The connection element is designed with multi-functionality: the penetration tip pierces the tank wall, the connection body provides mechanical attachment, and the sealing element prevents leakage. This universal design accomplishes multiple functions in a single component, avoiding the need for complicated multi-part assemblies.
3Productivity
If connection elements are integrated during extrusion blow molding, then productivity is improved, but manufacturing precision is required to ensure proper wall piercing and material flow connection
Solution Approach 1:
The penetration tip is designed with specific geometric features (sharp edge, appropriate diameter) that enable it to pierce the tank wall at the predetermined location during the extrusion blow molding process. This preliminary design of the piercing geometry ensures that the connection element can be integrated in one step without requiring high precision adjustments during production.
Solution Approach 2:
The connection element is designed to exploit parameter changes in the thermoplastic material during extrusion blow molding. As the material transitions from plasticized to solidified state, the penetration tip creates a clean opening and the material flows around the connection element, creating a secure mechanical connection without requiring high precision control.
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 allows for the simple and effective integration of connection elements during fuel tank production by extrusion blow molding, reducing hydrocarbon leakage and maintaining high permeation sealing integrity, while avoiding complex two-component structural parts.
Implementation Method 1
the container is provided with at least one connection element which passes through the wall of the container, wherein the wall of the container is pierced in the still plasticized condition with a part of the connection element
Implementation Method 2
the connection element entails a connection involving a flow of material with the container wall at least in partial regions
Data Source
AI summary
A process for the production of a container of thermoplastic material by extrusion blow molding is provided, in which during shaping of the container within a multi-part tool, the container is provided with at least one connection element (3) which passes through the wall of the container. The connection element (3) according to the invention, is of a two-part structure, wherein a part is in the form of a removal cutting element (11). The cutting element (11) serves as a penetration tip for piercing the wall of the container while still in the plastic condition.