Septum Design Using Composite Elastomer and Rigid Ring
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Solution Overview
Problem
Conventional silicone-based septa are not inert enough and can contaminate samples, while alternative materials face issues with stability and ease of use, particularly with needle punctures and cap attachment.
Innovation Solution
A septum design featuring a disc of elastomeric material, such as a fluorinated thermoplastic elastomer, with a rigid ring and additional openings, that can be pierced and resealed, and is not bonded to the cap, maintaining integrity without compressing the outer periphery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If silicone is used as the elastomeric material for the septum, then the septum is flexible and compressible to create a good seal, but the silicone is not inert and leaches chemicals into the sample
Solution Approach 1:
The septum is divided into two distinct layers: an inner PTFE layer that provides chemical inertness and an outer silicone layer that provides sealing and resealing capabilities. This segmentation allows each material to perform its optimal function without the drawbacks of the other.
Solution Approach 2:
The invention uses a composite structure combining PTFE and silicone materials in a layered configuration. The PTFE layer faces the sample to provide inertness, while the silicone layer provides the necessary elasticity for sealing, creating a material system that exhibits properties superior to either material alone.
2Object-generated harmful factors
If a PTFE layer is added to provide an inert barrier, then chemical contamination is prevented, but the PTFE layer is hard to puncture and does not reseal
Solution Approach 1:
The septum is divided into two distinct layers: an inner PTFE layer that provides chemical inertness and an outer silicone layer that provides sealing and resealing capabilities. This segmentation allows each material to perform its optimal function without the drawbacks of the other.
Solution Approach 2:
The invention uses a composite structure combining PTFE and silicone materials in a layered configuration. The PTFE layer faces the sample to provide inertness, while the silicone layer provides the necessary elasticity for sealing, creating a material system that exhibits properties superior to either material alone.
3Reliability
If the outer periphery of the elastomeric material is compressed between the cap and bottle to hold the septum in place, then the septum is secured, but the compression forces the flow of septa material away from the compression seal which is detrimental
Solution Approach 1:
A compression ring is introduced as an intermediary component between the cap and the elastomeric septum material. This ring distributes the compressive force evenly around the septum's periphery, preventing the material from being forced away from the seal area while still securing the septum in place.
Solution Approach 2:
The compression force is applied locally at the periphery of the septum rather than across the entire surface. The compression ring creates a localized compression zone that secures the septum without affecting the sealing material's position, maintaining local material quality where it is most needed.
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 septum effectively prevents contamination and maintains a secure seal without compressing the elastomeric material, supporting the septum in the cap and preventing material flow, ensuring reliable needle penetration and resealing.
Implementation Method 1
When a septum is punctured, for example, by a needle, compressed elastomeric material can create a seal around the needle as the needle is used to transfer material into or out of a vessel. When the needle is withdrawn from the septum, the compressed material forces the puncture closed and reseals the vessel.
Data Source
AI summary
A septum includes a disc made of an elastomeric material that is capable of being pierced by a needle and resealing itself when the needle is withdrawn. Embedded in the middle of the disc, from top to bottom, is a ring made of a material that is more rigid than the elastomeric material of the disc. The ring has a center circular opening that is filled by the elastomeric material of the disc. The outer circumference of the ring is greater than the circumference of the disc and extends outwardly beyond the circumference of the disc. The outer part of the ring interacts with the inner screw threads of a cap and supports the septum in the cap. A plurality of additional openings equally spaced about the ring adjacent its outer circumference are also filled with the elastic material of the disc to provide additional support for the septum.