Capsule Air-Vent Design for Leakage Prevention
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Solution Overview
Problem
Hard-shell capsules face leakage issues due to air pressure buildup during the final joining process, especially with liquid dosages, as existing air-vent designs only allow air escape on a limited range of engagement positions, leading to deformations and potential leaks during transfer between filling and sealing machines.
Innovation Solution
The capsule design features a hollow tubular body with a cap that provides continuous circumferential contact in the fully closed position, incorporating axially extending air-vents on the body that ensure fluid communication between the inner volume and atmosphere over a wider range of engagement positions, excluding the fully closed final position, where the cap seals tightly, and includes a spray ring for sealing fluid application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air-vents are formed by oval dimples extending across the locking ring, then air escape is enabled during capsule closing, but air escape is only allowed on a small range of engagement positions causing air pressure buildup and potential leakage
Solution Approach 1:
The air-vent is segmented into multiple axial sections: a first section extending from the open end toward the locking ring, and a second section extending from the locking ring toward the closed end. This segmentation allows the air-vent to maintain different functional characteristics in different zones, enabling extended air escape range while preserving sealing integrity at the locking ring location.
Solution Approach 2:
The air-vent transitions from a simple radial dimple to a three-dimensional axial recess that extends through multiple sections along the capsule axis. This dimensional extension along the axial direction significantly increases the range of engagement positions where air can escape, solving the limitation of small-range air escape in conventional designs.
2Strength
If the cap is locked in a fully closed final position with high retention force, then capsule integrity is ensured, but air pressure builds up during closing causing deformations and leakage
Solution Approach 1:
The air-vent is pre-configured to remain open during the closing process, allowing air to escape before the cap reaches the fully locked position. This preliminary air release prevents pressure buildup that would otherwise occur during the final stages of closing, enabling strong retention force without harmful pressure effects.
Solution Approach 2:
The design converts the potentially harmful air pressure buildup into a beneficial controlled release mechanism. The air-vent provides a designated escape path for air pressure, transforming what would be a harmful force causing deformation and leakage into a controlled process that actually aids the closing operation by preventing defects.
3Stress or pressure
If air escape is enabled over a wide range of engagement positions, then air pressure buildup is prevented, but the capsule may not achieve tight sealing in the final position
Solution Approach 1:
The air-vent is designed with non-uniform characteristics across different axial sections. The first section allows air escape during initial closing, while the second section's configuration ensures that air escape ceases before the cap reaches the fully locked position. This local variation in air-vent properties enables both wide-range air release and tight final sealing.
Solution Approach 2:
The air-vent dynamically transitions from an open state during the closing process to a closed state in the final locked position. The axial recess geometry is designed so that as the cap moves into the fully closed position, the air-vent becomes occluded by the cap's inner surface, automatically stopping air escape precisely when tight sealing is required.
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 design minimizes the risk of leakage by allowing air escape throughout the engagement process, preventing deformations and leaks, even during non-vertical transfers, and ensures a tight seal in large-scale manufacturing processes.
Implementation Method 1
at least one air-vent formed as an axial recess on the outer surface of the body and suitable for ensuring fluid communication between the inner volume and the atmosphere over a range of engagement positions of the cap on the body
Implementation Method 2
the body and the cap being provided with complementary snap-fit means for locking the cap on the body in the fully closed final position, the complementary snap-fit means comprising a locking ring formed by a channel on an axial section of the body and a complementary ridge member formed on the inner surface of the cap so as to protrude inwardly
Data Source
AI summary
The invention relates to a capsule comprising a hollow tubular body (2), a hollow cap (3) telescopically engageable on the body (2), the body (2) and the cap (3) defining an inner volume therebetween and being provided with complementary snap-fit means (12, 21) for locking the cap (3) on the body (2) in the fully closed final position, the complementary snap-fit means (12, 21) comprising a locking ring (12) formed on the body (2) and a complementary ridge member (21) formed on the cap (3), at least one air-vent (14) formed as an axial recess on the outer surface of the body (2) and suitable for ensuring fluid communication between the inner volume and the atmosphere. The capsule (1) is configured such that, in the fully closed final position, the inner surface of the cap (3) fits on the outer surface of the body (2) over a continuous circumferential contact section (33) and the air-vent (14) axially extends from the open end (5) of the body (2) toward the contact section (33), so as to provide fluid communication between the inner volume and the atmosphere over the whole range of engagement positions, excluding the fully closed final position wherein the inner surface of the cap (3) sealingly engages the outer surface of the body (2) over the contact section (33). Application to capsules for liquid dosages.