Metallic Container Closure Internal Pressure Release Design
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Solution Overview
Problem
Conventional metallic container closures with internal pressure release functions face issues such as deformation during wrap-seaming, incomplete pressure release, and top panel jumping or container breakage due to excessive pressure, especially when made from thin metal sheets with varying tensile strengths.
Innovation Solution
A metallic container closure design featuring a shell with a circular top panel and cylindrical skirt wall, incorporating a synthetic resin liner, an internal pressure release line with slits and low-strength bridging portions, and strategically positioned annular beads to prevent deformation during wrap-seaming, along with weakened lines that allow for controlled pressure release and prevent top panel separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If slits are provided in the upper portion of the skirt wall to form an internal pressure release line, then the internal pressure can be released when elevated, but the skirt wall deforms during wrap-seaming due to reduced strength at the slit portions
Solution Approach 1:
The patent applies local quality by creating regions with different mechanical properties in the skirt wall. Specifically, it provides slits with breakable bridging portions in the upper portion for pressure release, while providing reinforcing ribs in the lower portion to maintain strength during wrap-seaming. This localized differentiation allows each region to perform its specific function without interfering with the other.
Solution Approach 2:
The patent segments the skirt wall into distinct functional zones: an upper portion with slits and bridging portions for pressure release, a lower portion with reinforcing ribs for structural support during seaming, and intermediate connecting portions. This segmentation allows independent optimization of each zone for its specific purpose.
2Reliability
If the bridging portions among slits are made with small width to enable easy breaking for pressure release, then internal pressure can be released effectively, but the container closure may jump off or the container may break when pressure suddenly elevates
Solution Approach 1:
The patent applies local quality by creating regions with different mechanical properties in the skirt wall. Specifically, it provides slits with breakable bridging portions in the upper portion for pressure release, while providing reinforcing ribs in the lower portion to maintain strength during wrap-seaming. This localized differentiation allows each region to perform its specific function without interfering with the other.
Solution Approach 2:
The reinforcing ribs are provided beforehand in the skirt wall to cushion and distribute sudden pressure increases. These ribs act as a preemptive structural reinforcement that prevents catastrophic failure when pressure suddenly elevates, allowing the breakable bridging portions to function as intended for gradual pressure release.
3Strength
If a thin metal sheet with high tensile strength is used to improve resistance against drop impact, then the bridging portions are not broken even when pressure elevates and internal pressure cannot be released
Solution Approach 1:
The patent applies parameter changes by carefully controlling the dimensions and material properties of the bridging portions. Specifically, the bridging portions are designed with small widths (0.3-0.8mm) and specific lengths to create controlled weak points that will break at predetermined pressure levels, even when the overall container closure is made of high-strength thin metal sheet material.
Solution Approach 2:
The patent creates local variations in material properties by providing reinforcing ribs in certain regions while maintaining thin, breakable bridging portions in other regions. This allows the container closure to have high overall strength for drop impact resistance while maintaining localized weak points for pressure release functionality.
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
Effectively prevents deformation and ensures reliable pressure release without top panel jumping or container breakage, even when made from high-tensile strength materials, by forming a large opening for gas release and maintaining structural integrity under elevated pressures.
Implementation Method 1
when the pressure in the container is elevated, the bridging portions break, the plurality of slits in the circumferential direction become continuous to form a large slit, the gas in the container is released to the exterior through this portion
Implementation Method 2
an annular bead is provided in the skirt wall at a position below the internal pressure release line... effectively prevents deformation and ensures reliable pressure release
Implementation Method 3
along with weakened lines that allow for controlled pressure release and prevent top panel separation
Data Source
AI summary
A metallic container closure including a shell of a thin metal sheet having a circular top panel wall (7) and a skirt wall (9), and a synthetic resin liner arranged in the shell, the skirt wall (9) having a thread-forming region and an annular groove (17) positioned at an upper end portion of the thread-forming region, wherein an internal pressure release line A extending in the circumferential direction is arranged in the skirt wall (9) at a portion over the annular groove (17), and annular bead (30) is arranged so as to pass through between the internal pressure release line A and the annular groove (17).