Polymer Diaphragm Tear Path for Liquid Tin Sealing
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Solution Overview
Problem
Existing sealing systems for large-sized tins require excessive force to open, leading to discomfort and risk of leakage due to the positioning of the line of weakness in the most stressed area, which also poses challenges in compliance with safety standards for transporting dangerous goods.
Innovation Solution
A stopper with a diaphragm featuring a tear path that includes a semi-circular section and a supporting wedge, allowing for a twisting motion to reduce the required force for opening, and a line of weakness positioned in less stressed areas to enhance structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the line of weakness is positioned in the central portion of the diaphragm to ensure airtightness, then the sealing reliability is improved, but the force required to open the tin increases excessively
Solution Approach 1:
The patent applies local quality by positioning the line of weakness at a specific radial distance (R1 to R2) from the central axis, creating a localized weak zone that is optimized for tearing. This allows the central portion to maintain full depth for sealing reliability while the peripheral zone provides easier opening, resolving the contradiction between sealing strength and opening force.
Solution Approach 2:
The line of weakness is pre-formed during manufacturing at an optimized position and depth, preparing the diaphragm for controlled tearing. This preliminary action ensures that when the user applies force to the gripping element, the tear propagates along the pre-defined path with reduced force requirement, while the overall diaphragm structure remains intact for sealing.
2Reliability
If the line of weakness is positioned in the central portion of the diaphragm, then the airtightness is ensured, but the structural integrity during pressure tests deteriorates
Solution Approach 1:
The line of weakness is positioned in the peripheral zone (radial distance R1 to R2 from center) rather than the central portion, creating a localized tear path that preserves the structural integrity of the central diaphragm area. This allows the diaphragm to withstand hydraulic pressure and impact tests while maintaining a defined tear path for opening.
3Reliability
If a deep line of weakness is used to ensure airtightness, then the sealing performance is improved, but the tearing force required increases
Solution Approach 1:
The line of weakness depth is optimized locally at different radial positions. At the peripheral zone (R1 to R2), the line of weakness has sufficient depth to ensure sealing while being shallow enough to allow easy tearing. The central portion maintains full depth for maximum sealing performance, creating a gradient structure that balances sealing and opening requirements.
Solution Approach 2:
The patent optimizes the parameters of the line of weakness (depth, radial position, angle) to achieve the desired balance between sealing and opening force. By adjusting these parameters within specific ranges, the system achieves both reliable sealing and easy opening without requiring excessive tearing force.
4Reliability
If the line of weakness is positioned centrally for sealing, then the airtightness is maintained, but the user comfort during opening deteriorates
Solution Approach 1:
The line of weakness is positioned in the peripheral zone of the diaphragm rather than the central portion, creating a localized opening zone that is easier to access and tear. This peripheral positioning allows users to apply tearing force more effectively without requiring excessive arm movement, improving ergonomics while maintaining central sealing integrity.
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 solution reduces the force needed to open the tin, improves ergonomics, and enhances the structural integrity of the diaphragm to withstand pressure and impact tests, while simplifying the manufacturing process of the line of weakness.
Implementation Method 1
sealing systems of the type described above are made of a polymeric material, namely a material that deforms plastically
Data Source
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AI summary
A tin for liquids, in particular paints, provided with a sealing system with an stopper (8) (8;) made of a polymeric material and having a diaphragm (18) configured to be torn out, in use, at the moment of the first opening; said diaphragm (18) having a removable portion (19), which is delimited laterally by at least one line of weakness (20; 201, 2011); the removable portion (19) having a gripping element (21) which is configured to be grabbed, in use, by a user; said diaphragm (18) having an incision (k) extending along a side perimeter (p1) and locally reducing the depth of the diaphragm (18); wherein a portion of said incision (k) along the perimeter (p1) constitutes a respective part of one of the lines of weakness (20; 201, 2011).