Lightweight container base
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Solution Overview
Problem
Current PET container bases are not optimized for balanced vacuum and pressure response, leading to inefficiencies in material usage and weight, particularly under hot-fill conditions where they must absorb internal and external pressures while maintaining container shape.
Innovation Solution
The design incorporates a lightweight base configuration with a central pushup portion and strategically positioned straps, which allows for improved vacuum absorption and structural integrity, reducing material usage and weight while maintaining performance under pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If traditional container base design is used, then structural integrity is maintained, but container weight increases and material usage is inefficient
Solution Approach 1:
The base is divided into multiple functional zones including a heel region, a pushup portion with inversion portion, and a standing surface region. This segmentation allows each zone to be optimized for its specific function while using minimal material, resolving the contradiction between weight reduction and structural integrity.
Solution Approach 2:
Different regions of the base are given different thicknesses and material densities based on their functional requirements. The heel region has greater thickness for impact absorption, the pushup portion is optimized for vacuum response, and the standing surface is minimized for weight reduction. This local differentiation maintains overall structural integrity while minimizing total material usage.
2Weight of moving object
If base material is reduced to minimize weight, then container weight decreases, but ability to absorb vacuum forces and withstand pressure deteriorates
Solution Approach 1:
The base incorporates a pushup portion with an inversion portion that can dynamically change shape in response to vacuum forces. During hot filling, the inversion portion pushes up to counteract vacuum. During cooling, it inverts to absorb vacuum forces. This dynamic response allows the lightweight base to maintain reliable vacuum and pressure response without excessive material.
Solution Approach 2:
The base design changes the physical parameters of the container base by creating a pushup portion that actively changes position and shape under different pressure conditions. This parameter change enables the lightweight structure to achieve the same vacuum and pressure response as heavier traditional bases.
3Reliability
If base design is optimized for vacuum absorption, then vacuum response improves, but ability to withstand internal pressure during hot filling deteriorates
Solution Approach 1:
The pushup portion dynamically adapts its shape based on pressure conditions. During hot filling, it maintains a pushed-up configuration to withstand internal pressure. During cooling, it inverts to absorb vacuum forces. This dynamic behavior allows a single lightweight structure to excel at both vacuum absorption and pressure withstanding.
Solution Approach 2:
The base is pre-formed with a pushup portion that is positioned to counteract vacuum forces before they occur during hot filling. This preliminary positioning allows the lightweight base to effectively resist vacuum without requiring excessive material, while still maintaining the strength needed for pressure withstanding.
Data Source
AI summary
A container including an opening defined by a finish portion, and a base at an end of the container opposite to the opening. The base includes a standing ring extending inward from a heal to a center pushup portion. The center pushup portion includes an pushup ring surrounding an inversion portion. In an as-blown position the inversion portion extends outward and beyond the pushup ring such that the inversion portion is further from the opening than the pushup ring. In a final position the inversion portion is inverted relative to the as-blown position such that the inversion portion extends inward so as to be closer to the opening than the pushup ring. The inversion portion is mechanically moved from the as-blown position to the filled position with an inversion device after the container has been filled to reduce vacuum or increase pressure within the container.