Aerosol Piston Flow Passages Prevent Vacuum Seal
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Solution Overview
Problem
Barrier package aerosol containers (BPA containers) fail to dispense the entire amount of flowable product due to vacuum pressure causing the piston to deform and form a seal at the interface with the container or valve, trapping residual material and leading to variations in the amount dispensed, necessitating overfilling to comply with regulatory requirements.
Innovation Solution
The BPA container design includes a piston with flow passages at the interface between the piston, can, and valve, which allows residual product to flow through even after vacuum-induced deformation, ensuring consistent dispensing of nearly all product by preventing the formation of a vacuum-induced seal that restricts flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the piston is allowed to deform under vacuum pressure to form a seal at the interface, then product containment is improved, but product dispensing completeness deteriorates due to trapped residual material
Solution Approach 1:
The interface between the piston and valve/can is segmented into multiple separate contact points rather than a continuous seal. The piston's distal end features a non-planar surface with peaks and valleys that create discrete contact regions, allowing the piston to maintain structural integrity while preventing continuous vacuum-induced sealing that would trap product.
Solution Approach 2:
Different regions of the piston's distal end are given different geometric properties. The non-planar surface creates localized contact zones with varying pressure distribution, ensuring that sealing occurs only at specific points rather than uniformly across the entire interface, thus allowing product to flow through non-contact regions.
2Manufacturing precision
If overfilling is implemented to comply with regulatory requirements, then regulatory compliance is improved, but device complexity and manufacturing cost worsen due to additional filling adjustments
Solution Approach 1:
The piston's non-planar distal end automatically regulates product dispensing by its geometric design alone, without requiring external control mechanisms or complex filling procedures. The peaks and valleys configuration self-regulates to ensure complete product ejection, making the system self-correcting and eliminating the need for overfilling compensations.
3Ease of manufacture
If a planar piston interface is used, then manufacturing simplicity is improved, but product flow consistency deteriorates due to vacuum-induced seal formation
Solution Approach 1:
The piston's distal end employs an asymmetric non-planar surface design with deliberately created peaks and valleys. This asymmetric geometry breaks the symmetry of vacuum pressure distribution that would otherwise cause uniform sealing across a planar interface, ensuring consistent product flow paths while remaining manufacturable through standard machining processes.
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 ensures that nearly all flowable product is dispensed, minimizing variations between containers and allowing for accurate compliance with weights and measures regulations without the need for overfilling, as the flow passages ensure consistent product delivery.
Implementation Method 1
vacuum pressure causing the piston to deform and form a seal at the interface with the container or valve
Implementation Method 2
one or more flow passages at the piston interface to allow flowable material in the interstitial space to flow through the piston interface toward the valve inlet during use
Data Source
AI summary
A barrier package aerosol container includes a can, valve, and piston disposed in the interior volume of the can. The piston is movable toward a top end of the can to facilitate dispensing of flowable material in the can. Opposing surfaces of the piston and the can and the valve define an interstitial space of the interior volume in which the flowable product is receivable. The piston is contacts at least one of the interior surface of the can at its top end and the valve, to define a piston interface when the piston is at the top end of the can during use. At least one of the piston, the can, and the valve defines one or more flow passages at the piston interface to allow flowable material in the interstitial space to flow through the piston interface toward the valve inlet during use.