Injection Apparatus Rupture Seal Membrane Design
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Solution Overview
Problem
Conventional injection devices, such as pre-filled syringes and auto-injectors, face challenges in maintaining sterility and preventing medicament exposure to needle materials, especially for sensitive formulations, and can be difficult for patients with limited dexterity to use due to additional steps required for needle attachment.
Innovation Solution
An injection apparatus featuring a hollow body with a bung and piston configuration, where a rupture seal membrane isolates the medicament from the needle until pressure is applied, allowing medicament expulsion through a connected needle without direct contact, and includes a protrusion on the piston to maximize medicament delivery and reduce waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pre-filled syringe or cartridge is used to maintain sterility and prevent medicament exposure to needle materials, then the medicament remains isolated and sterile, but additional steps are required for needle attachment which complicates operation for patients with limited dexterity
Solution Approach 1:
The needle is permanently integrated into the hollow body of the injection apparatus, eliminating the separate needle attachment step. The rupture seal membrane serves as both the sterile barrier and the interface through which medicament is delivered to the needle, merging the sealing function and delivery function into a single integrated structure.
Solution Approach 2:
The rupture seal membrane is extracted as a separate functional element that can rupture under fluid pressure to create a fluid pathway between the medicament reservoir and the needle, allowing the needle to remain in place while enabling controlled medicament flow.
2Object-affected harmful factors
If the needle is kept separate from the medicament until injection time to prevent exposure to needle materials, then medicament sensitivity to needle materials is avoided, but the device complexity increases due to additional assembly steps
Solution Approach 1:
The rupture seal membrane acts as an intermediary barrier between the medicament and the needle. It maintains separation during storage and transport, then allows controlled contact during injection when it ruptures under fluid pressure, enabling the needle to remain permanently attached without causing premature medicament degradation.
3Reliability
If a rupture seal membrane is used to isolate the needle from medicament until pressure is applied, then sterile delivery is ensured, but the membrane must be configured to rupture through fluid pressure alone without contacting the needle which adds design complexity
Solution Approach 1:
The rupture seal membrane has different structural properties at different locations: the central portion is designed to rupture under fluid pressure to create an opening, while the peripheral portion maintains attachment to the bung to prevent needle contact. This local differentiation of membrane properties enables both sterile delivery and controlled rupture.
4Productivity
If the piston is designed with a protrusion to maximize medicament delivery and reduce waste, then medicament expulsion efficiency is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The protrusion on the piston is designed to extend into the aperture of the bung at the end of medicament expulsion, preliminarily positioning itself to maximize the volume of medicament delivered. This preliminary geometric configuration ensures complete evacuation of the medicament reservoir without requiring complex control systems.
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 ensures sterile delivery of medicament by preventing prolonged exposure to needle materials, simplifies the manufacturing process, and enhances user accessibility by minimizing additional steps, particularly benefiting patients with dexterity issues.
Implementation Method 1
The rupture seal membrane is configured to rupture through fluid pressure alone, without the rupture seal membrane contacting the needle, thereby to allow the medicament to be expelled through the needle upon movement of the piston causing the provision of pressure to the medicament.
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3C
AI summary
An injection apparatus comprises a hollow body having a first end at which a hollow needle is or can be located. A bung with a rupture seal membrane is located within the hollow body. A piston is also located within the hollow body. The piston, the hollow body and the bung define a volume containing a liquid medicament. The bung is nearer than the piston to the first end of the hollow body. The rupture seal membrane initially isolates the needle from the medicament. The rupture seal membrane is configured to rupture through fluid pressure alone without the rupture seal membrane contacting the needle,thereby allowing the medicament to be expelled through the needle upon movement of the piston causing the provision of pressure to the medicament. In some embodiments, he piston comprises a protrusion located on the side of the piston which faces the first end of the hollow body, the protrusion shaped so as to extend into an aperture in the bung at the end of medicament expulsion. In other embodiments, the bung comprises at least two oppositely oriented rupture seal membranes, with one configured to rupture under fluid pressure from a first side of the bung and another configured to rupture under fluid pressure from the other side of the bung.