Flexible-Closure Aerosol Piston for Complete Product Dispensing

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Solution Overview

Problem

Current piston aerosol containers face issues with residual product retention, sealing failures due to can expansion, and pulsating dispensing, particularly when used with plastic containers and viscous products, leading to increased piston stiction and difficulty in dispensing all product.

Innovation Solution

A piston design featuring an upper side made of an elastic material with a shore A hardness of 50 to 90, a sidewall of a different material, and a circumferential seal on the sidewall, which deforms under pressure to maintain a seal with the container, allowing for a gas-tight and liquid-tight interface, suitable for plastic containers and various viscosities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If rigid plastics are used for the piston to dispense viscous products, then the piston can maintain structural integrity, but the sidewalls retain residual product and sealing fails due to can expansion

Engineering Contradiction:
Improveproduct dispensing capabilityVSAvoidsealing performance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention changes the material parameter of the piston from rigid plastic to elastic material with specific shore A hardness (50-90). This parameter change allows the piston to deform elastically under pressure, maintaining sealing contact with the can wall while accommodating can expansion, thereby resolving the sealing failure issue while maintaining product dispensing capability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses composite construction by combining elastic material for the piston body with a circumferential seal made of sealing material. This composite approach leverages the elasticity of the main body for structural integrity and the specialized sealing material for maintaining contact and preventing leakage, thus resolving both productivity and reliability concerns

Inventive Principle:
Principle #40Composite materials

2Reliability

If piston interference is increased to overcome can expansion and roughness, then sealing improves, but piston stiction increases causing pulsating spray and dispensing failure

Engineering Contradiction:
Improvesealing performanceVSAvoidpiston movement smoothness
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention optimizes the interference fit parameters by using elastic material with controlled shore A hardness (50-90) instead of rigid material. This allows sufficient interference for sealing while the elastic deformation capability prevents excessive stiction, enabling smooth piston movement and eliminating pulsating spray

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The elastic piston acts as a flexible element that can deform to accommodate interference fit requirements for sealing while returning to its original shape during movement. This flexibility maintains reliable sealing contact without creating excessive friction that would cause pulsating spray or dispensing failure

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If viscous product is used as sealing agent between piston and can wall, then sealing is achieved, but residual product is retained in the sidewalls

Engineering Contradiction:
Improvesealing performanceVSAvoidproduct retention
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The invention introduces a circumferential seal made of specialized sealing material as an intermediary between the elastic piston and the can wall. This intermediary component performs the sealing function, allowing the viscous product to be dispensed without relying on the product itself as the sealing agent, thereby eliminating residual product retention in the sidewalls

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design ensures complete dispensing of products, maintains a seal throughout the container's lifetime, and supports dispensing of both liquid and viscous products without residual retention, even at high pressures up to 180 psig.

Implementation Method 1

the upper side is made of a first elastic material, wherein the upper side is configured to deform upon a pressure change acting on the upper side

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3489171B1Piston with flexible closure for aerosol container
Publication Date: 2026.03.18 PROCTER & GAMBLE CO
  • EP3489171B1 patent drawingFigure 1~2
  • EP3489171B1 patent drawingFigure 3~4
  • EP3489171B1 patent drawingFigure 5~6

AI summary

The invention relates to a piston for an optionally pressurized container, the piston having a sidewall, an upper side and a bottom side, and at least a first circumferential seal, wherein at least the upper side of the piston is closed by a closure and made of a first elastic material, wherein the upper side is configured to deform upon a pressure change acting on the upper side, wherein the sidewall is made of a second material which is different from the first elastic material, wherein the first circumferential seal is positioned on the sidewall on its outer surface. The invention further relates to an optionally pressurized container comprising a piston as mentioned above, to a process of discharging a product from said container and to a process of manufacturing said container.