Vial Adapter Sealing Element for Snap-Fit Leakage Prevention
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Solution Overview
Problem
Fluid transfer devices often cause tears in medicinal vial stoppers during snap fitting, leading to leakage issues during drug reconstitution and administration, due to initial misalignment and the elastic nature of the stoppers, which existing solutions fail to adequately address.
Innovation Solution
A vial adapter with a pointed tubular cannula and an elastic O-ring like sealing element that encircles the cannula, compressing axially to maintain a continuous seal around the puncture site, effectively sealing any tears formed during snap fitting, regardless of alignment issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a pointed cannula is used for piercing the vial stopper during snap fitting, then the fluid transfer device can be quickly mounted on the vial, but tears may form in the stopper leading to leakage
Solution Approach 1:
The sealing element is pre-positioned on the cannula in a retracted state before mounting. During the snap-fit process, it automatically moves into position to seal the puncture site, performing the sealing action in advance preparation without requiring separate manual intervention.
Solution Approach 2:
The sealing element acts as an intermediary component between the cannula and the vial stopper. It is mounted on the cannula and interfaces with the stopper material to prevent leakage, mediating the interaction between the piercing cannula and the elastic stopper.
2Ease of operation
If the vial adapter is designed with a flared skirt for guiding alignment, then ease of mounting is improved, but initial misalignment may still cause skewed or eccentric positioning leading to tears
Solution Approach 1:
The alignment function is extracted from the flared skirt and transferred to the sealing element. The sealing element incorporates alignment features (such as a beveled leading surface) that actively guide the cannula into proper alignment with the vial axis during insertion, separating the alignment function from the guiding skirt structure.
Solution Approach 2:
The sealing element's geometry parameters (such as the beveled angle of its leading surface) are designed to change the interaction dynamics during insertion. The beveled surface gradually engages the stopper material, transforming the insertion process from a direct sharp entry to a controlled progressive engagement that maintains alignment.
3Reliability
If the sealing element is positioned to seal the puncture site, then leakage is prevented, but the element must be disposed of after single use
Solution Approach 1:
The sealing element is designed as a single-use, disposable component that is inexpensive to manufacture. Its short service life (one use only) is acceptable because it ensures reliable sealing performance without the complexity of making it reusable, and the low cost makes disposal economically acceptable.
Solution Approach 2:
The sealing element is discarded after single use to prevent contamination and ensure sterility. The system is designed so that the disposable nature of the sealing element (and entire fluid transfer device) simplifies waste management and eliminates the need for complex sterilization or recovery processes.
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 prevents leakage by ensuring a hermetic seal around the puncture site, maintaining continuous contact and sealing any tears that occur during the snap fitting process, thus preventing liquid or negative pressure leaks in medicinal vials.
Implementation Method 1
an elastic O-ring like sealing element disposed along a cannula and sealingly encircling same... whereupon the sealing element extends radially outward to cover a greater area on the uppermost stopper surface
Implementation Method 2
to be slidingly urged along a cannula towards a top wall as a fluid transfer device snap fits onto a vial to maintain continuous sealing contact with a puncture site
Data Source
Figure 1~2
Figure 3A~3C
Figure 3D~3E
AI summary
The present invention is directed toward fluid transfer devices including a vial adapter having a top wall and a cannula with a cannula tip, and an elastic O-ring like sealing element sealingly encircling the cannula and initially disposed towards the cannula tip and spaced apart from the top wall, the sealing element being brought into initial contact with the vial stopper subsequent to the cannula tip contacting the vial stopper at a puncture site and thereafter being slidingly urged towards the top wall and continuously sealing the puncture site during snap fit mounting the vial adapter on the vial.