Non-Circular Drop Dispenser Surface for Residual Droplet Reduction

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Solution Overview

Problem

Generic drop dispensers often leave a residual droplet on the drop formation surface, which can cause contamination and drying hazards, as the existing solutions like geometry modifications and elastic outlet tubes are insufficient in minimizing the residual droplet volume effectively.

Innovation Solution

The drop formation surface has a non-circular outer boundary contour with inward concave indentations, and a deformable housing mechanism, such as a squeeze bottle design, to reduce the residual droplet volume by altering the shape of the surface and preventing liquid from flowing back into the reservoir.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a circular droplet formation surface is used, then the main droplet size is maintained, but the residual droplet volume is large causing contamination risks

Engineering Contradiction:
Improvemain droplet volumeVSAvoidcontamination risk from residual droplet
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The droplet formation surface uses a non-circular outer boundary contour with indentations that create asymmetric geometry. This asymmetric shape causes the liquid to distribute differently during dispensing, allowing the main droplet to form properly while the residual droplet is funneled into the indentations, reducing its volume and contamination risk.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The invention introduces a new geometric dimension by adding indentations to the droplet formation surface. These indentations create additional spatial zones that capture and contain the residual droplet, effectively using the surface geometry to separate the main droplet formation area from the residual droplet accumulation zones.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If the droplet formation surface area is reduced to minimize residual droplet, then contamination is reduced, but the main droplet size is also reduced

Engineering Contradiction:
Improvecontamination from residual dropletVSAvoidmain droplet volume
Core Design Contradiction:
Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The droplet formation surface is segmented into distinct functional zones by the indentations: a main droplet formation area and residual droplet collection zones within the indentations. This segmentation allows the surface to handle both functions simultaneously - producing adequate main droplets while capturing residual liquid in separate compartments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the droplet formation surface have different local geometries optimized for different functions. The main area maintains sufficient size for proper droplet formation, while the indentated regions provide localized zones for residual droplet capture, giving each part the quality it needs for its specific function.

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If a non-circular droplet formation surface with indentations is used, then residual droplet volume is reduced, but the manufacturing complexity increases

Engineering Contradiction:
Improveresidual droplet volumeVSAvoidmanufacturing complexity of droplet formation surface
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The non-circular contour with indentations can be manufactured using standard molding or machining techniques. The asymmetric geometry is achieved through conventional manufacturing processes, making the increased complexity manageable and cost-effective compared to the benefits of reduced contamination.

Inventive Principle:
Principle #4Asymmetry

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 significantly reduces the residual droplet volume, with the residual droplet being approximately half the size of what would remain on a circular surface, while maintaining comparable main droplet size, thus minimizing contamination risks.

Implementation Method 1

a droplet formation surface surrounding the dispensing opening, on which the liquid collects in order to be dispensed as drops from the droplet formation surface

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Implementation Method 2

the liquid collects on the droplet formation surface

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP2698134B1Drop dispenser
Publication Date: 2015.06.03 APTAR RADOLFZELL
  • EP2698134B1 patent drawingFigure 1
  • EP2698134B1 patent drawingFigure 2~3
  • EP2698134B1 patent drawingFigure 4a~4c

AI summary

1. Liquid dispenser for dispensing drops. 2.1. Drop dispensers (10) are known, comprising a housing (12, 14), a liquid reservoir (12), a dispensing opening (20) through which liquid can be dispensed from the liquid reservoir (12), and a droplet-forming surface (30) surrounding the dispensing opening (812), on which the liquid collects to be dispensed as drops from the droplet-forming surface (30). 2.2. It is proposed that the droplet-forming surface (30) has an outer boundary contour (32) whose shape deviates from a circular shape. 2.3. Use to avoid contamination of the dispensed liquid.