Cannula Support Radial Projection Sealing Fluid Dispensing Leaks
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Solution Overview
Problem
Existing single-dose or two-dose fluid product dispensing devices suffer from leaks during actuation, affecting dosage precision and reproducibility, and are prone to manufacturing complexities.
Innovation Solution
A fluid product dispensing device with a cannula support featuring a central axial bore and a radial projection of reduced internal diameter, which seals the cannula and plug during actuation, minimizing leak volume and simplifying manufacturing by eliminating undercutting requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cannula support has a central bore with longitudinal ribs for cannula fixation, then the cannula is securely fixed in the support, but liquid can flow into the entire central bore volume causing leaks and dosage errors
Solution Approach 1:
The central bore is segmented into two distinct zones: an upper portion with sufficient diameter for cannula insertion and fixation, and a lower portion with reduced diameter that prevents liquid accumulation. This segmentation allows the same bore to simultaneously fulfill both cannula fixation and leak prevention functions.
Solution Approach 2:
Different sections of the central bore have different internal diameters tailored to their specific functions. The upper section has a larger diameter for easy cannula insertion and secure fixation, while the lower section has a reduced diameter to prevent liquid from entering and accumulating, thereby addressing the harmful effect locally where it occurs.
2Reliability
If the cannula support has a complex internal structure with ribs and bore variations, then cannula fixation and leak prevention are improved, but manufacturing complexity increases
Solution Approach 1:
The internal diameter parameter of the central bore is varied along its length to create functional zones. By changing the diameter parameter from the upper portion to the lower portion, the patent achieves both secure cannula fixation and leak prevention without requiring complex additional structures, thereby reducing overall device complexity while maintaining reliability.
3Ease of manufacture
If the cannula support bore has uniform internal diameter, then manufacturing is simpler, but liquid can freely flow through causing dosage imprecision
Solution Approach 1:
The bore is divided into functional segments with different diameter characteristics. The upper segment maintains a uniform, larger diameter for ease of manufacture and cannula insertion, while the lower segment transitions to a reduced diameter to prevent liquid accumulation. This segmentation allows the patent to balance manufacturing simplicity with dosage precision requirements.
Solution Approach 2:
The bore structure implements local quality by having different diameter characteristics in different regions. The upper portion has one diameter for manufacturing ease and cannula fixation, while the lower portion has a reduced diameter specifically where liquid flow control is critical, thereby achieving dosage precision without compromising overall manufacturability.
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 solution significantly reduces leaks, enhances dosage precision and reproducibility, and simplifies manufacturing, as demonstrated by improved statistical performance metrics such as lower standard deviation and higher Cp and Cpk values, with minimal out-of-specification doses and leaks.
Implementation Method 1
the internal diameter d2 of said radial projection being less than the internal diameter d1 of said central axial bore... after insertion of the cannula into the cannula support, said radial projection cooperates in a sealed manner with said cannula
Implementation Method 2
said reservoir comprising a hollow tube having a proximal axial opening closed by a plug adapted to slide sealingly in said tube during actuation
Implementation Method 3
limiting the volume likely to receive leaks during operation... the distal axial end of said cannula support comprising a radial projection extending radially inwards
Data Source
Figure 1
Figure 2~6
AI summary
The invention relates to a device for dispensing a fluid product, which device comprises a body (1) and a dispensing head (2) provided with a dispensing opening (3) and axially movable relative to said body (1) during actuation, said body (1) receiving a vessel (10) containing a fluid product, said vessel (10) comprising a hollow tube (11) having a proximal axial opening (12) closed by a plug (20) suitable for sealingly sliding inside said tube (11) upon actuation, said dispensing head (2) comprising a hollow cannula (4) connected on one side to said dispensing opening (3) and provided on the other side with a puncturing tip (5) provided with an opening (6) and intended for puncturing said plug (20), said cannula (4) being inserted into a cannula holder (9) rigidly connected to said dispensing head (2), said cannula holder (9) comprising a central axial bore with an inner diameter which is equal to or slightly greater than the outer diameter of said cannula (4), the distal axial end of said cannula holder (9) comprising a radial projection extending radially inwards, the inner diameter of which is equal to or very slightly smaller than the outer diameter of said cannula (4), the inner diameter of said radial projection being smaller than the inner diameter of said central axial bore.