Needleless Injector Wave-Shaped Seal Design
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Solution Overview
Problem
Existing needleless injection devices face issues with leakage due to the design of conventional seals, which can overflow and pinch, leading to inefficiencies in sealing between the reservoir and nozzle, especially during the injection process.
Innovation Solution
The introduction of a wave-shaped radial section upper seal with recessed and raised portions that lie down under axial pressure, preventing pinching and creeping, and an additional lower seal to ensure closure with the cap, both made from thermoplastic elastomer for chemical adhesion with the nozzle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional seal is compressed axially between the reservoir and nozzle, then sealing is achieved, but the seal overflows and pinches, causing leakage
Solution Approach 1:
The seal is designed with a wave-shaped radial section featuring convex and concave portions instead of a conventional flat or simple curved shape. This wave configuration allows the seal to deform in a controlled manner under axial compression, with the convex portions being compressed and the concave portions receiving the displaced seal material, preventing overflow and pinching that lead to leakage.
2Reliability
If the seal is compressed axially, then sealing contact is established, but the seal forms lobes that bypass injection channels, creating pinching points
Solution Approach 1:
The wave-shaped radial section with its alternating convex and concave portions redistributes the compression deformation. The convex portions make contact and seal against the nozzle surface, while the concave portions accommodate the lobes formed by the seal material, preventing pinching at the lobes and ensuring continuous sealing contact without bypassing the injection channels.
3Reliability
If the seal material is compressed, then sealing pressure is applied, but the seal flows outwards between nozzle and reservoir
Solution Approach 1:
The wave-shaped radial section provides designated concave regions that act as receptacles for the seal material under compression. Instead of flowing outward uncontrollably between the nozzle and reservoir, the seal material is directed into the concave portions of the wave shape, maintaining sealing pressure while preventing outward flow and potential leakage paths.
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 configuration enhances the tightness of the nozzle, preventing leakage and ensuring effective sealing during injections, maintaining the integrity of the active ingredient delivery.
Implementation Method 1
the raised portion being adapted to lie flat towards the recessed portion provided for this purpose, under the effect of the axial pressure exerted by the lower face of the tank on said sealing joint
Data Source
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AI summary
The invention relates to a needleless injector (10) comprising an injection system (28) having at least one injection nozzle (28) defining at least one injection channel (72) and axially delimited by a top face 60 arranged opposite the bottom face 38 of the reservoir 24, and a bottom face 62 designed to cooperate with a closing element 64, the injector also having a top seal 78 which extends around the at least one channel 72 and is housed in a top neck 80 provided in the top face 60 of the nozzle 28, characterised in that the top seal 78 has a curved radial section having successively in a radial direction a recessed portion 86 and a protruding portion 88, the protruding portion 88 being designed to be folded onto the recessed portion 86 provided for that purpose, under the axial pressure applied by the bottom face 38 of the reservoir 24 to the seal 78.