Modular Dispensing Plunger Cross-Section Change

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Solution Overview

Problem

Collapsible cartridges often leave residual volumes due to the inability of dispensing plungers to fully compress the cartridge wall, especially when creases form during collapse, leading to inefficiencies in dispensing flowable substances.

Innovation Solution

A dispensing plunger with a modular design featuring two parts that can change cross-sections, allowing for a larger first cross-section to compress the cartridge laterally and a smaller second cross-section to further dispense residual volume, utilizing a coupling and decoupling mechanism without additional drives, ensuring minimal residual volume.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a single cross-section dispensing plunger is used, then the device structure is simple, but residual volume remains in the cartridge due to inability to fully compress the cartridge wall

Engineering Contradiction:
Improveresidual volumeVSAvoiddispensing plunger structure
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The dispensing plunger is divided into a first plunger and a second plunger with different cross-sections. The first plunger has a larger cross-section for initial compression, while the second plunger has a smaller cross-section for final compression to access residual volume. This segmentation allows the system to address different stages of cartridge collapse with appropriately sized plungers, thereby minimizing residual volume without requiring an overly complex single-plunger design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The dispensing plunger system dynamically changes its effective cross-section during the dispensing process by switching between the first and second plungers. This dynamic adaptation allows the system to optimize compression effectiveness at different stages of cartridge collapse, transitioning from a larger cross-section for bulk material displacement to a smaller cross-section for accessing remaining material in collapsed regions.

Inventive Principle:
Principle #15Dynamics

2Force

If the dispensing plunger cross-section is increased to compress the cartridge wall, then compression effectiveness improves, but the ability to access residual volume in collapsed regions decreases

Engineering Contradiction:
Improvecartridge wall compressionVSAvoidresidual volume
Core Design Contradiction:
ForceVSQuantity of substance

Solution Approach 1:

The plunger system is segmented into two distinct components with different cross-sectional areas. The first plunger provides high force through its larger cross-section for effective cartridge wall compression, while the second plunger provides access to residual volume through its smaller cross-section that can navigate into collapsed regions. This segmentation resolves the contradiction by assigning different functional roles to different plunger segments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the dispensing system (first plunger vs. second plunger) are given different local qualities in terms of cross-sectional size. The first plunger is designed with a larger cross-section optimized for force application and wall compression, while the second plunger is designed with a smaller cross-section optimized for penetrating into collapsed cartridge regions to access residual material. Each local region of the plunger system has properties tailored to its specific function.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3043928B1Dispensing plunger, dispensing apparatus comprising the dispensing plunger and method
Publication Date: 2020.06.03 SULZER MIXPAC AG
  • EP3043928B1 patent drawingFigure 1~2
  • EP3043928B1 patent drawingFigure 3~4
  • EP3043928B1 patent drawingFigure 5~7

AI summary

The invention relates to a dispensing plunger (1) for a dispensing apparatus (2). The dispensing apparatus (2) is suitable for the reception of a cartridge (3) containing a dispensable medium. The dispensing plunger (1) can be arranged at and/or in the dispensing apparatus (2), wherein the dispensing plunger (1) has an end face (4) which can act on the cartridge (3) for a dispensing of the medium out of the cartridge (3). The dispensing plunger (1) is configured in such a way that the end face (4), during the dispensing of the medium, has at least a first dispensing cross-section (5) and subsequently has at least a second dispensing cross-section. The first dispensing cross-section (5) and the second dispensing cross-section in particular have a different size and/or shape.