Invertible Diaphragm for Hot-Fill PET Container Rigidity
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Solution Overview
Problem
Existing hot-fill containers made of PET lack rigidity after being opened and are prone to bending under external stresses when stacked or palletized, due to the loss of pressure and flexibility of their pressure panels.
Innovation Solution
A container design featuring an invertible diaphragm with a curved outer and inner portion that maintains pressure and rigidity, allowing the diaphragm to be inverted and locked in position, thereby maintaining internal pressure and preventing the diaphragm from sinking back, ensuring the container remains stable under external stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the pressure panel is made flexible to compensate for pressure changes, then the container adapts to internal pressure changes, but the container loses rigidity once opened and bends under external stresses
Solution Approach 1:
The diaphragm is designed to dynamically change its configuration between an inverted position during stacking (providing rigidity) and a non-inverted position during use (providing flexibility). This dynamic reconfiguration allows the container to adapt to different operational requirements, resolving the contradiction between needing flexibility for pressure adaptation and rigidity for structural strength.
2Strength
If the pressure panel is forced into an inwardly-inclined position to maintain rigidity, then the container withstands external stresses, but the panel sinks back under content pressure and the container loses rigidity
Solution Approach 1:
The inverted diaphragm configuration creates a geometric structure where the curved surfaces and support elements act as counterbalancing features. When the diaphragm is inverted, its shape and the associated support structures provide mechanical counteraction against the inward pressure from the content, preventing the diaphragm from sinking back and maintaining stable rigidity.
3Adaptability or versatility
If numerous hinges and panels are provided in the pressure panel, then the container adapts to pressure changes, but the structure becomes complex and cannot withstand vertical compression stresses
Solution Approach 1:
The diaphragm is segmented into distinct functional zones including a curved portion, a transition zone, and support elements. This segmentation allows each zone to perform its specific function - the curved portion adapts to pressure changes while the support elements and transition zone provide structural stability and simplify the overall structure, reducing complexity while maintaining adaptability.
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 maintains high rigidity and stability when handled or stacked, preventing unintentional splashes and pallet collapse by maintaining pressure and structural integrity through the diaphragm's inverted position.
Implementation Method 1
The important volume swept by the diaphragm between the outwardly-protruding position and the inwardly-protruding position increases the pressure inside the container
Implementation Method 2
Pressure within the container is thereby maintained to a high value, providing high rigidity to the container
Data Source
Figure 1
Figure 2~3
Figure 4~7
AI summary
Container (1) made of a plastic material, provided with a base (7) including a standing ring (8) forming a support flange (9) and a diaphragm (11) extending from the standing ring (8) to a central portion (10), said diaphragm (11) being capable of standing in an outwardly-inclined position, wherein the diaphragm (11) connects to the standing ring (8) at an outer junction (12) forming an outer articulation of the diaphragm (11); wherein the diaphragm (11) connects to the central portion (10) at an inner junction (13) forming an inner articulation of the diaphragm (11); whereby said diaphragm (11) is invertible with respect to the standing ring (8) from the outwardly-inclined position to an inwardly-inclined position; and wherein, in the outwardly-inclined position, the diaphragm (11) has an outer curved portion (16) and an inner curved portion (17) of opposite curvatures.