Self-Venting Closure Rib Design for Pressure Relief
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Solution Overview
Problem
Existing container closures fail to effectively vent excess pressure without compromising sealability or flexibility, leading to issues like doming, sink marks, and reduced sealing performance, especially in aseptic products.
Innovation Solution
A closure design featuring a substantially circular base with a radially extending rib, where the end of the rib in contact with the bore seal is thinner than the opposite end, allowing for efficient pressure relief while minimizing sink marks and maintaining flexibility, and potentially including multiple non-regularly spaced ribs to adjust venting pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rib of uniform thickness is provided to transfer doming force to the bore seal for venting, then pressure relief function is improved, but sink marks are formed on the bore seal surface compromising sealability
Solution Approach 1:
The rib is designed with varying thickness along its length, with the end portion in contact with the bore seal being thinner than the root portion. This local variation in geometry allows the rib to transfer doming forces effectively while minimizing sink mark formation on the bore seal surface, thereby maintaining sealability.
2Manufacturing precision
If the rib is made thinner to reduce sink marks, then sealability is improved, but the ability to transfer doming force for venting is reduced
Solution Approach 1:
The rib exhibits non-uniform thickness distribution: the root portion maintains sufficient thickness to provide structural support and force transfer capability, while the end portion is thinned to minimize sink marks. This localized differentiation resolves the contradiction between sealability and venting function.
Solution Approach 2:
The rib is effectively segmented into different functional zones along its length - a thicker root zone for structural integrity and force transmission, and a thinner end zone for minimizing surface deformation. This segmentation allows each zone to optimize its local function.
3Ease of operation
If the bore seal is made more flexible to allow easy fitting, then ease of operation is improved, but sealability under pressure may be compromised
Solution Approach 1:
The bore seal exhibits varying flexibility along its axial length, with the lower portion being more flexible to facilitate easy fitting and the upper portion maintaining sufficient rigidity to ensure reliable sealing under pressure. This localized differentiation in mechanical properties resolves the contradiction between ease of operation and sealability.
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
Enables self-venting of containers without affecting sealability or fitting ease, reducing the risk of sudden pressure release and ensuring proper sealing, even in aseptic conditions.
Implementation Method 1
During venting, the thinned portion of the base acts as a hinge allowing the portion of the base, including the part which has the bore seal depending from it, to move upwards.
Implementation Method 2
As the closure domes, the rib will transmit the doming force from the centre of the closure to the bore seal. This force will pull the bore seal radially inwards.
Data Source
AI summary
A closure 10 for a container, comprises a substantially circular base 20, a skirt 30 extending from the periphery thereof, a bore seal 50 in the form of an annulus and a rib 70 lying on the surface of the base 20 in a substantially radial direction and in contact with the radially inner surface of the bore seal 50 at one end for transferring any movement of the center of the base 20, relative to the skirt 30, to the bore seal 50 such that the bore seal 50 is pulled radially inward to allow venting of excess pressure within the container, wherein the end of the rib 70 in contact with the radially inner surface of the bore seal 50 is substantially thinner, in a plane parallel to the base 20, than the other end of the rib 70.