Plastic Container Base Diaphragm for Vacuum Absorption
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Solution Overview
Problem
Existing manufacturing processes for plastic beverage containers struggle to produce containers with deep inset bases without causing extreme stretching and thinning of the container wall, leading to deformities such as crimping or folding of the standing ring.
Innovation Solution
A plastic container design featuring a base with a diaphragm that curves downward from a hinge to a central region, allowing the base to respond to pressure changes within the container by moving axially. The diaphragm can be asymmetric with a combination of curved and linear profiles, enabling it to buckle and provide a visual indicator of its activated position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the container is designed with a deep inset base using conventional stretch blow molding, then the container can accommodate volumetric shrinkage and provide stable stacking, but the container wall experiences extreme stretching and thinning causing crimping or folding of the standing ring
Solution Approach 1:
The patent applies the dynamics principle by designing a movable vacuum panel in the base that can flex and move dynamically in response to pressure changes during hot-fill processing. This movable panel accommodates volumetric shrinkage without requiring the entire base structure to be deeply inset, thereby preventing standing ring deformities while maintaining the ability to absorb volume changes during cooling
Solution Approach 2:
The base is segmented into a movable vacuum panel portion and a fixed standing ring portion. This segmentation allows the vacuum panel to independently flex and accommodate volume changes without transmitting excessive stress to the standing ring, thus preventing crimping or folding while maintaining structural integrity
2Force
If pressure is applied from the top during filling to support the container, then the container remains stable during fill, but the base sags or rolls out below the heel causing the container to tip over
Solution Approach 1:
The movable vacuum panel provides dynamic structural support that adapts to pressure changes during filling. As pressure is applied from the top, the panel flexes appropriately to distribute forces evenly, preventing base sagging while maintaining heel integrity and overall container stability throughout the filling process
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
The container design effectively accommodates pressure changes and volumetric shrinkage, preventing deformities and ensuring the container remains stable and resistant to tipping, while also allowing for proper sealing and handling during manufacturing and use.
Implementation Method 1
the base of the plastic container has a diaphragm that curves downward from a hinge to a central region. As pressure changes within the sealed container, the central region moves axially
Implementation Method 2
the diaphragm has an asymmetric flexible wall that includes a first portion with a curved profile and a second portion with a linear profile. In the activated position, for example, the diaphragm may buckle, providing a visual indicator of the base being in the activated position
Data Source
AI summary
A plastic container has a base portion adapted for vacuum absorption, the container including a base and a body extending up from the base along a central axis to a finish portion defining a mouth. The base includes an outside wall, a chime connecting the outside wall to an annular contact ring, an inside wall extending upward from the contact ring to a hinge, and a diaphragm connected to the hinge. The diaphragm can move between first and second positions in response to pressure change within the container. The diaphragm includes a central region and a flexible wall having a curved profile in cross section. The flexible wall curves downward from the hinge to the central region. In some embodiments, the flexible wall is asymmetric and includes a first portion having a curved profile and a second portion having a linear profile. A container wall structure is also disclosed.