Plastic Pressure Container Finish Undercut Sealing Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing plastic pressure containers face challenges in withstanding high internal pressures and providing effective sealing due to their material limitations and design considerations, which lead to issues like rust and surface scratching, and inadequate sealing between the container finish and closure assembly.
Innovation Solution
A plastic pressure container design featuring a finish portion with both inner and outer undercuts that securely engage the closure assembly through crimping, providing multiple points of contact and enhanced sealing, and fabricated from materials like polyethylene terephthalate or other polyester-based polymers, capable of withstanding pressures up to 160 psi.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal containers are used for pressure containers, then they can withstand high internal pressures, but they tend to rust over time and scratch surfaces
Solution Approach 1:
The patent changes the material parameter from metal to plastic (specifically high-density polyethylene or similar plastics), fundamentally altering the chemical composition to eliminate rust and scratching properties while maintaining pressure containment capability through appropriate plastic material selection and design
Solution Approach 2:
The patent employs composite construction by combining the plastic container body with a separate closure assembly that includes its own sealing mechanisms and structural elements, creating a hybrid system that leverages the corrosion resistance of plastic while providing robust sealing through the integrated closure design
2Object-affected harmful factors
If plastic material is used for pressure containers, then rust and surface scratching are prevented, but the material may not withstand high internal pressures
Solution Approach 1:
The patent selects specific plastic materials with appropriate mechanical properties (such as high-density polyethylene, polypropylene, or other pressure-resistant plastics) and adjusts structural parameters including wall thickness, reinforcement ribs, and overall geometry to achieve the necessary pressure withstanding capability while maintaining the inherent corrosion resistance of plastic
Solution Approach 2:
The patent employs a cylindrical container shape with carefully designed curvature radii at transitions and joints, which distributes stress more evenly throughout the structure and prevents stress concentration points that would otherwise limit the pressure withstanding capability of plastic material
3Ease of manufacture
If a simple finish portion design is used, then manufacturing is easier, but effective sealing between the finish and closure assembly cannot be achieved
Solution Approach 1:
The patent incorporates pre-formed sealing surfaces, undercuts, and engagement features directly into the mold during finish portion fabrication. These features are created in advance as integral parts of the molding process, ensuring proper sealing geometry is established before the closure assembly is applied, thereby guaranteeing effective sealing while maintaining manufacturing efficiency
Solution Approach 2:
The patent introduces a sealing member (such as a gasket, O-ring, or integral sealing flange) that acts as an intermediary element between the finish portion and closure assembly. This sealing member fills minor dimensional variations and creates a reliable seal, mediating the interface between the two components to ensure leak-proof performance
4Strength
If a closure assembly mounting system is designed for high pressure, then pressure containment is improved, but the mounting structure becomes more complex
Solution Approach 1:
The patent combines multiple functions into the closure assembly structure: the closure body integrates the sealing surface, the crimping engagement features, and the external threading or attachment mechanisms. By merging these elements into a single integrated component rather than separate parts, the design achieves robust pressure containment while minimizing overall structural complexity
Data Source
AI summary
A plastic pressure container including a main body portion and a finish portion defining a mouth, the finish portion has an inner surface, an outer surface and an upper rim proximate the mouth. The inner surface has an inner undercut defined therein proximate the upper rim, and the inner undercut has a curved shape in cross-section. The outer surface has an outer undercut defined therein proximate the upper rim, and the outer undercut has a polygonal shape in cross-section. The inner undercut defines a first depth relative to an inner diameter D2 proximate the mouth and the outer undercut defines a second depth relative to an outer diameter D3 proximate the mouth. The second depth is different than the first depth.