Cap Gasket Bent Part Biasing for Carbonated Beverage Sealing
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Solution Overview
Problem
Conventional two-piece caps with synthetic resin gaskets fail to maintain airtightness at high internal pressures, such as in carbonated beverages, due to the doming phenomenon, leading to potential leakage.
Innovation Solution
The cap features a synthetic resin gasket with an inclined bent part that is biased downward by a biasing part of the cap main body, a tamper evidence band connected via breakable bridges, and a swelling part on the inner leg that optimizes sealing, along with a thicker top wall to prevent doming, and the inclusion of sodium sulfite for oxygen absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the wall thickness of the top wall is increased to prevent doming phenomenon, then the cap can maintain structural integrity under high internal pressure, but the bent part is not pushed against the container mouth part and sealing performance deteriorates
Solution Approach 1:
The cap is divided into two separate pieces: a cap main body and a gasket. This segmentation allows the cap main body to be designed with sufficient wall thickness for structural strength, while the gasket is specifically designed with the bent part mechanism to ensure sealing performance independently.
Solution Approach 2:
The design changes the physical state and positioning parameters of the gasket through the bent part mechanism. By designing the bent part to be pushable against the container mouth part, the system transforms the static sealing structure into a dynamic one that can maintain sealing under high internal pressure regardless of cap wall thickness.
2Stress or pressure
If the cap main body is made with sufficient wall thickness to prevent doming, then high internal pressure can be withstood, but the pushing force on the bent part is insufficient and leakage occurs
Solution Approach 1:
The gasket acts as an intermediary element between the cap main body and the container mouth part. The bent part of the gasket is specifically designed to be pushed by the cap main body against the container mouth part, creating an additional sealing mechanism that prevents leakage even when the cap wall thickness is sufficient to prevent doming.
3Ease of manufacture
If a conventional two-piece cap structure is used, then manufacturing is simplified, but sealing performance under high internal pressure deteriorates due to doming phenomenon
Solution Approach 1:
Instead of uniformly thickening the entire cap to prevent doming, the design applies local quality enhancement only where needed: the gasket is given a specific bent part structure at the sealing location. This allows conventional manufacturing for the cap main body while adding a specialized sealing component to ensure performance under high internal pressure.
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
This configuration enhances sealing performance, prevents abnormal noise during opening, and ensures high tamper evidence and long-term preservation of contents by improving the engagement of the gasket with the container mouth part and absorbing oxygen.
Implementation Method 1
the biasing part of the cap main body biases the bent part downwardly in the closed state
Implementation Method 2
the gasket contains sodium sulfite
Data Source
Figure 1(A)~1(B)
Figure 2
Figure 3
AI summary
The present invention provides a cap capable of improving sealing performance of a container, and suited for use in the case where the internal pressure of the container is high, for example, when the contents of the container is carbonated beverage, and a container having the cap. The present invention includes a cap main body having a top wall and a skirt wall pending from an outer circumferential part of the top wall, the skirt wall being provided with an internal thread that comes in screw engagement with an external thread of a container mouth part, and a gasket made of synthetic resin for hermetically sealing the container mouth part, wherein the gasket has a top plate that comes in abutment with a distal end part of the container mouth part to cover the distal end part, and an annular inner leg pending from the top plate, adapted to close fit with an inner circumferential face of the container mouth part, and an outer circumferential edge of the top plate is continuously formed with an annular bent part that bends downward with respect to the top plate and has the inner circumferential face covering an outer circumferential face of the container mouth part, and the cap main body has a biasing part that biases an outer circumferential face of the bent part of the gasket in a closed state, so that the biased bent part elastically deforms to be pushed against the outer circumferential face of the container mouth part.