Dispensing Assembly With Membrane Sealing to Limit Trapped Air

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Solution Overview

Problem

Existing dispensing cartridges for one-component and multi-component materials suffer from reduced storage life due to air trapped between the piston and the material, leading to premature reaction and degradation.

Innovation Solution

A dispensing assembly with a piston and a membrane that moves relative to the dispensing end to reduce air inclusion, featuring a hermetically sealed space between the membrane and piston, and a piston cover with venting channels to expel air, using materials like elastomers and metals for stability and chemical resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If cartridges are filled with piston already positioned or filled from end where piston is received, then filling process is simple, but air is trapped between piston and material reducing storage life

Engineering Contradiction:
Improvefilling process simplicityVSAvoidstorage life
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The filling process is divided into two distinct phases: first filling the cartridge with material, then inserting the piston separately. This segmentation allows complete evacuation of air before piston insertion, eliminating the air trapping problem while maintaining filling simplicity through standardized sequential operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cartridge is completely filled with material before the piston is inserted. This preliminary action ensures that all air is displaced by the material during filling, and when the piston is subsequently inserted, no air remains between the piston and material, thus preserving storage life without complicating the overall manufacturing process.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If cartridges are made from materials that do not react with stored masses and are kept clean, then storage life is extended, but manufacturing complexity increases

Engineering Contradiction:
Improvestorage lifeVSAvoidcartridge manufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention changes the temporal parameter of the filling process by separating material filling from piston insertion. This parameter change allows the use of standard, chemically inert cartridge materials without requiring complex reactive coating processes, thus extending storage life while avoiding increased manufacturing complexity.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If a membrane is added to cover the dispensing end, then air inclusion is reduced and storage life extended, but device complexity increases

Engineering Contradiction:
Improvestorage lifeVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A flexible membrane is positioned at the dispensing end to seal against the piston surface. This thin film creates a hermetic seal that prevents air inclusion when the piston is inserted, significantly extending storage life. The membrane's flexibility allows it to conform to the piston surface, achieving effective sealing with minimal structural complexity.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The membrane acts as an intermediary element between the piston and the external environment. It provides the necessary hermetic seal to prevent air contamination while allowing the simple piston insertion mechanism to function, thus extending storage life without requiring complex sealing mechanisms.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If hermetic sealing is implemented between membrane and piston, then air presence is minimized, but manufacturing precision requirements increase

Engineering Contradiction:
Improvestorage lifeVSAvoidsealing precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The flexible membrane compensates for manufacturing tolerances through its elasticity. When the piston is inserted, the membrane deforms to conform to the piston surface, creating an effective hermetic seal even with moderate manufacturing precision. This flexibility eliminates the need for ultra-precise sealing surfaces while achieving the required air-tight seal for extended storage life.

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP4585318A1Dispensing assembly
Publication Date: 2025.07.16 MEDMIX SWITZERLAND AG
  • EP4585318A1 patent drawingFigure 1A~1B
  • EP4585318A1 patent drawingFigure 2A~2B
  • EP4585318A1 patent drawingFigure 3A~3B

AI summary

The present invention relates to a dispensing assembly comprising a piston and a membrane.