Pierceable Cap Frangible Seal for Vessel Leakage Prevention
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Solution Overview
Problem
Existing caps for biological and chemical specimen vessels are prone to leakage during transport and analysis, leading to contamination risks and false positives in nucleic acid detection assays, as they often require physical removal and can create aerosols when pierced, which may spread pathogens and alter assay results.
Innovation Solution
A pierceable cap design featuring a shell with a lower frangible layer and one or more upper frangible layers, where the extensions move to breach the lower layer upon pressure application, allowing air to vent and minimizing specimen transfer before and after piercing, thereby reducing contamination and aerosol formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional screw cap is used to seal the vessel, then the seal is substantially leak-proof during transport, but the cap must be physically removed which creates contamination risk and aerosol formation
Solution Approach 1:
The cap is segmented into multiple functional layers: a non-frangible outer cap structure and an inner frangible seal layer. This segmentation allows the outer cap to maintain seal integrity during transport while the inner frangible layer can be pierced without removing the entire cap, thus eliminating contamination risk during access.
Solution Approach 2:
The frangible seal layer is pre-positioned within the cap structure before use. This preliminary arrangement ensures that when a piercing device is inserted, the seal is already in place to prevent contamination, and the piercing action occurs within the controlled environment of the cap rather than requiring cap removal.
2Ease of operation
If the cap is pierced to allow specimen transfer, then access to the specimen is enabled, but aerosols may be released into the surrounding environment
Solution Approach 1:
The frangible seal layer acts as an intermediary between the specimen and the external environment. When pierced, it controls the interface between the sealed vessel interior and the external atmosphere, allowing specimen access through the piercing device while maintaining a barrier that prevents uncontrolled aerosol release.
Solution Approach 2:
The piercing action, which could potentially cause aerosol formation, is converted into a beneficial controlled process. The frangible seal layer is designed to pierce in a controlled manner that actually reduces aerosol formation compared to traditional methods, transforming the potential harm into a benefit by providing a controlled access pathway.
3Ease of operation
If a frangible layer is used to allow piercing, then specimen transfer is enabled, but jetting droplets may contaminate the surrounding environment
Solution Approach 1:
The frangible seal layer is constructed as a thin, flexible film that can be pierced without causing violent rupture. This flexible membrane structure allows controlled penetration while absorbing the energy of the piercing action, preventing droplet jetting that would occur with rigid sealing materials.
Solution Approach 2:
The cap assembly uses composite materials combining the structural integrity of a rigid outer cap with the controlled-fracture properties of a frangible seal layer. This composite structure enables piercing capability while the frangible layer's material properties prevent droplet jetting by providing a controlled failure mode.
4Reliability
If the vessel is sealed to prevent leakage, then specimen protection is improved, but pressure buildup from temperature changes may occur
Solution Approach 1:
The frangible seal layer is designed with specific material parameters that allow it to accommodate pressure changes from temperature variations. The seal's physical properties are engineered to maintain integrity under normal temperature fluctuations while still allowing controlled piercing when accessed, thus managing internal pressure without compromising leak prevention.
Data Source
Figure 1A~1D
Figure 1E~1G
Figure 2A~2B
AI summary
A pierceable cap comprising: a shell (634); an access port in the shell (634) adapted to allow passage of at least part of a transfer device (25) through the access port; a frangible seal (612) comprising at least two intersecting ribs (620, 621), a collar (623), wherein the intersecting ribs (620, 621) each extend from the collar (623) and comprise end wall (624, 625) and sidewall portions (629) to a bottom surface (626) of the frangible seal (612) having an intersecting openable or tearable portion (630);characterized in thatthe end wall (624, 625) and sidewall portions (629) extend simultaneously inward in a radial direction and downward in an axial direction, such that surfaces of the end wall (624, 625) and sidewall portions (629) are not parallel to an inside surface of a sample vessel (631) when such vessel has been disposed within the shell (634).