Vacuum Panels in Hot Fill PET Containers
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Solution Overview
Problem
Hot-filled PET containers experience deformation, lack gripping convenience, and are prone to buckling during storage or transit due to vacuum pressure, which affects their structural integrity and aesthetic appeal.
Innovation Solution
A blow-molded plastic container design featuring diagonal, concave vacuum panels with compound angles that accommodate internal vacuum pressure and enhance hand gripping, along with horizontal and vertical ribs to increase structural strength and resist top loading, while minimizing material usage and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If multiple vertical or horizontal ribs are placed in the container to increase moment of inertia, then container body strength is improved, but the amount of plastic material used increases, contributing to overall weight and size
Solution Approach 1:
The container sidewall is segmented into multiple functional elements: vertical ribs for structural strength, vacuum panels for vacuum accommodation, and gripping zones for usability. This segmentation allows each element to perform its specific function efficiently without requiring excessive material throughout the entire structure.
Solution Approach 2:
Different regions of the container sidewall have different structural properties optimized for their specific functions. Vertical ribs provide localized strength where needed, vacuum panels provide localized vacuum accommodation, and gripping zones provide localized ergonomic features, rather than uniformly thickening the entire container wall.
2Shape
If the container is designed to accommodate vacuum pressure, then deformation is reduced, but the container may still be susceptible to buckling during storage or transit under vertical loading
Solution Approach 1:
The sidewall is divided into vertical ribs, vacuum panels, and gripping zones, creating a segmented structure that addresses multiple functional requirements simultaneously while maintaining overall structural integrity under various loading conditions.
Solution Approach 2:
The vacuum panels are formed with compound angles and curved surfaces that naturally accommodate vacuum pressure through their geometric design. The curvature and angular features provide structural rigidity that resists both vacuum-induced deformation and external compressive loads during storage and transit.
3Ease of operation
If gripping areas are designed on the container body, then ease of handling is improved, but the container may deform under vacuum pressure at these same areas
Solution Approach 1:
The container sidewall features localized gripping zones with specific geometric features optimized for hand contact, positioned in regions that provide ergonomic advantages without compromising structural integrity under vacuum pressure.
Solution Approach 2:
The gripping zones incorporate curved surfaces and geometric features that conform to hand shape for ergonomic handling, while the overall panel geometry and compound angles maintain structural rigidity to prevent deformation under vacuum loading.
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 structural integrity and resistance to top loading, reduces deformation, and allows for easier handling by accommodating vacuum pressure effectively, thus preventing buckling and enhancing usability and durability.
Implementation Method 1
as the product cools to room temperature, a negative internal pressure or vacuum forms within the sealed container
Implementation Method 2
the container body or sidewalls to deform in unacceptable ways to account for the pressure differential between the space inside of the container and the space outside
Data Source
AI summary
A container structure for a hot fill liquid may employ an upper portion defining a mouth, a shoulder portion integrally formed with and extending downward from the upper portion, a bottom portion defining a base, and a body and sidewall extending between and joining the shoulder and bottom portions. The sidewall may employ a pair of opposing columns oriented diagonally relative to the base and concave inward relative to a container central vertical axis before the container is filled. The columns become concave inward to a lesser extent when the bottle is under an interior vacuum. The sidewall may also employ a pair of opposing, compound angle vacuum panels oriented diagonally relative to the base. A vacuum initiator groove is formed in each of the vacuum panels to initiate panel movement during liquid content cooling. The vacuum initiator groove is generally coincident with a vacuum panel longitudinal centerline.