Auto-injection Syringe Vent Device for Sterility and Pressure Equalization
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Solution Overview
Problem
Existing auto-injection syringes face challenges in maintaining the fluid path in a sterile or aseptic condition and have complex, time-consuming assembly processes, which complicates their use and increases costs.
Innovation Solution
An auto-injection syringe with a vent device that includes a porous plastic end cap to equalize pressure and maintain a sterile or aseptic area, allowing for easy assembly and sterilization, and a retraction assembly with a partially biased spring to secure seals, ensuring the needle remains sterile before use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a self-retracting needle mechanism is incorporated to mitigate needle stick injuries, then safety is improved, but device complexity increases and assembly becomes more time-consuming
Solution Approach 1:
The device is divided into separate modules: a syringe body and a retraction assembly that can be assembled together by the user. The retraction assembly contains the needle and retraction spring as integrated components, simplifying the overall structure while maintaining safety functionality.
Solution Approach 2:
The retraction spring is pre-loaded and positioned within the retraction assembly before user assembly, so that the safety function is self-configured without requiring complex adjustment or calibration by the user during assembly.
2Reliability
If the needle is maintained in a sealed sterile area, then sterility is maintained, but pressure equalization becomes difficult and assembly complexity increases
Solution Approach 1:
The end cap is made from porous plastic material that allows pressure equalization between the sterile interior area and the exterior environment. The porous structure permits gas molecule passage while blocking larger contaminants, maintaining sterility through the filtration effect of the porous material.
Solution Approach 2:
The porous end cap acts as an intermediary barrier that mediates between the sterile interior and non-sterile exterior, allowing pressure equilibrium while preventing contamination. This single component simultaneously achieves both pressure equalization and sterility maintenance.
3Manufacturing precision
If the syringe is designed as a single integrated unit, then manufacturing precision can be maintained, but assembly time increases and costs increase
Solution Approach 1:
The device is segmented into a syringe body and a separate retraction assembly that can be manufactured independently with optimized processes for each component, then quickly assembled by the user through a simple engagement mechanism.
Solution Approach 2:
The retraction spring and needle are pre-positioned and pre-loaded within the retraction assembly during manufacturing, so that these critical components are already in their correct positions and configurations before the user performs the final assembly with the syringe body.
4Ease of operation
If the retraction spring is fully compressed during storage, then the device is ready for immediate use, but pressure differences can overcome the spring force and compromise sterility
Solution Approach 1:
The porous end cap allows pressure equalization between the interior sterile area and exterior environment, preventing pressure differences from building up to levels that could overcome the retraction spring force and compromise the sterile seal.
Solution Approach 2:
The porous end cap serves as a pressure-regulating intermediary that prevents external pressure fluctuations from directly affecting the balanced spring system, thereby maintaining sterility while keeping the device ready for use.
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 syringe effectively maintains sterility during storage and use, allows for quick and easy assembly, and separates the medicine cartridge from the syringe, extending the useful life of the injection and retraction assemblies while preventing contamination and reducing waste due to expired vaccines.
Implementation Method 1
The end cap is defined by a porous plastic material, which allows venting to equalize pressure between the sterile and/or aseptic area and an exterior of the syringe
Data Source
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AI summary
An auto-injection syringe is provided that includes an injection assembly and a retraction assembly operatively securable to the injection assembly. The retraction assembly includes a hypodermic needle having a needle hub, an end cap having a lower seal through which a portion of the hypodermic needle can pass, a retraction spring disposed between the needle hub and the end cap and maintained in a partially compressed condition therebetween, an upper seal urged against a facially sealing surface of the retraction assembly by the force of the retraction spring on the needle hub so that a sealed area is defined between the upper and lower seals, and a vent device in fluid communication with the sealed area for pressure equalization between the sealed area and an exterior of the retraction assembly.