Pharmaceutical Dropper Orifice Geometry for Low Residual Drips
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Solution Overview
Problem
Existing droppers for dispensing pharmaceutical liquids face the issue of residual drops that can cause contamination due to drying on the drop formation surface or being sucked back into the dispenser, leading to potential contamination risks during multiple uses.
Innovation Solution
The dropper design features a discharge orifice with an inner circumferential drip shoulder having different radial widths and a non-circular shape, which reduces the volume of residual drops by modifying the drop formation process, ensuring consistent main drop size and minimizing residual contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional circular drop formation surface is used, then the main drop can be dispensed, but a large residual drop remains on the surface causing contamination
Solution Approach 1:
The patent applies asymmetry by changing the drop formation surface from a conventional circular shape to a non-circular shape with specific geometric features. The outlet contour includes straight sections at 0°, 60°, 120°, 180°, 240°, and 300° positions, creating an asymmetric configuration that prevents residual drop accumulation while maintaining consistent main drop dispensing. This asymmetric geometry disrupts the formation of large residual drops that typically remain on circular surfaces.
Solution Approach 2:
The patent utilizes curvature principles by incorporating a drip shoulder with a specific radius of curvature (R1 = 0.5 mm) and designing the outlet contour with curved sections transitioning between straight segments. The concave curvature of the drip shoulder and the rounded corners at each 60° position create controlled flow patterns that minimize residual drop volume while ensuring smooth liquid discharge.
2Object-affected harmful factors
If the residual drop volume is reduced, then contamination risk decreases, but the main drop size consistency may be affected
Solution Approach 1:
The asymmetric outlet contour with straight sections at specific angular positions (0°, 60°, 120°, 180°, 240°, 300°) creates a balanced distribution of liquid flow that maintains consistent main drop size while minimizing residual drop formation. The symmetry in the angular distribution compensates for the asymmetric shape, ensuring reproducible dispensing characteristics.
Solution Approach 2:
The patent employs parameter changes by optimizing the outlet contour geometry with specific dimensions: R1 = 0.5 mm for the drip shoulder curvature, R2 = 0.25 mm for corner radii, and wall thickness t = 0.5-1.5 mm. These precisely controlled geometric parameters ensure both consistent main drop size and minimal residual drop volume through optimized fluid dynamics.
3Object-affected harmful factors
If a non-circular outlet contour is used to reduce residual drop, then contamination is minimized, but the device complexity increases
Solution Approach 1:
The outlet contour is segmented into six identical straight sections separated by 60° angles, with each section having the same length and geometric properties. This segmentation approach simplifies manufacturing by allowing modular production and ensures consistent performance through repetition of the same geometric pattern around the circular perimeter.
Solution Approach 2:
The non-circular outlet contour serves multiple functions simultaneously: it minimizes residual drop volume, maintains consistent main drop size, facilitates manufacturing through segmented geometry, and ensures proper liquid flow distribution. The unified design achieves contamination reduction without requiring additional components or complex assembly steps.
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 allows for repeated delivery of drops with consistent volume while significantly reducing the residual drop volume, enhancing accuracy and reducing contamination risks, particularly effective for viscous liquids and angled dispensing.
Implementation Method 1
The discharged liquid is received in the area of the outlet orifice and forms a drop there, which detaches from the dropper dispenser after reaching a certain size
Implementation Method 2
The outlet orifice has a capillary orifice shape having an inlet contour and an outlet contour
Data Source
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Figure 3a
AI summary
Dropper (1) for dispensing a pharmaceutical liquid forming a drop, comprising a liquid reservoir (2) and a dropper head (3), wherein the dropper head (3) includes a channel (5) ending in an outlet orifice (6), wherein an outlet valve (7) is associated with the outlet orifice (6), and the outlet orifice (6) has a capillary orifice shape with an inlet contour (8) and an outlet contour (9) and the inlet contour (8) forms an inner annular orifice (18) on the outlet side of a central valve body (10) of the outlet valve (7), wherein the capillary (12) of the outlet orifice (6) is divided by at least one radially outwardly extending annular shoulder (16), wherein with respect to said annular shoulder (16) the outlet contour (9) extends with a shape deviating from a circular shape, and the annular shoulder (16) forms an inner-walled drip step with circumferentially different radial widths (B1, B2) with respect to the annular opening (18) in the inlet contour (8).