Self-Sealing Elastomeric Plug for NMR Rotor Venting
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Solution Overview
Problem
Conventional NMR rotor inserts leak due to capillary action, leading to contamination and sample interference, and existing solutions complicate sample handling and are not cryogenically stable.
Innovation Solution
A self-sealing elastomeric plug with a vent tube is used to prevent air from getting trapped during insertion, allowing air to escape and forming a hermetic seal, which can be easily removed without contaminating the sample, using materials like silicone rubber that maintain integrity under cryogenic conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional Teflon plug with vent hole is used, then air can escape during insertion, but liquid leaks through the plug and rotor wall due to capillary action
Solution Approach 1:
The patent uses an elastomeric material (flexible shell) to form the plug body that can deform to create a liquid-tight seal against the rotor wall. The flexibility allows the material to conform to the rotor opening and prevent capillary leakage while maintaining structural integrity during insertion and removal operations.
Solution Approach 2:
The plug is segmented into functional zones: an outer sealing portion that contacts the rotor wall to prevent liquid leakage, and an inner vent channel portion that allows air escape. This segmentation allows simultaneous achievement of liquid-tight sealing and air venting functions without interference between them.
2Reliability
If additional protection layers (glue, silicone rubber, wax) are added between insert and cap, then leakage is prevented, but sample volume is reduced, removal is complicated, and contamination risk increases
Solution Approach 1:
The patent merges multiple functions into a single integrated elastomeric plug: sealing against the rotor wall, providing an air vent channel, and preventing liquid leakage. This consolidation eliminates the need for separate protection layers like glue or wax, reducing component count and assembly complexity while maintaining reliable leakage prevention.
Solution Approach 2:
The elastomeric material's physical parameters (flexibility, elasticity, chemical inertness) are optimized to provide both sealing and venting functions. The material's ability to deform under compression creates the seal, while its inherent porosity or engineered channels provide air escape paths, achieving leakage prevention without additional components.
3Reliability
If a tightly-fitting plug is used to prevent leakage, then liquid-tight seal is achieved, but air becomes trapped during insertion causing pressure increase
Solution Approach 1:
The elastomeric plug acts as an intermediary between the air inside the rotor and the external environment during insertion. It provides a controlled interface through which air can escape via the vent channel while preventing liquid from leaking outward, thus mediating the pressure equalization process without compromising the liquid seal.
Solution Approach 2:
The plug is designed with pre-formed vent channels that are prepared in advance to allow air escape during insertion. This preliminary configuration of the venting pathway ensures that air can escape before pressure builds up, preventing the harmful effect of trapped air while the tight fit maintains liquid sealing.
4Ease of operation
If the plug is made removable for easy sample access, then sample handling is improved, but seal reliability may be compromised
Solution Approach 1:
The elastomeric plug is designed to be dynamically removable and reinsertable while maintaining seal integrity. Its elastic properties allow it to be pulled out for sample access and then pushed back in to re-establish the liquid-tight seal. The material's ability to return to its original shape after deformation ensures reliable sealing upon reinsertion.
Solution Approach 2:
The elastomeric plug is self-sealing upon reinsertion without requiring additional components or complex procedures. When pushed back into the rotor opening, the material's elasticity causes it to automatically conform to the rotor wall and close the vent channel, restoring the liquid-tight seal through its own physical properties rather than requiring external assistance.
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 solution provides a reliable, leak-proof seal that maintains sample integrity and facilitates easy removal of the plug, preventing contamination and ensuring consistent NMR measurements across thermal cycles.
Implementation Method 1
a self-sealing elastomeric material to close the canal formed by the tube and to form a hermetic seal
Implementation Method 2
leak liquid through the plugged vent hole and between the insert and rotor wall due to capillary action
Data Source
AI summary
A closed container having a single opening is sealed by a plug fabricated from a self-sealing elastomer. Before insertion, the plug is transfixed with a tube to allow air to escape as the plug is pushed into the container. The plug and tube are then inserted into a container. After the plug has been seated in the container, the tube is withdrawn, allowing the self-sealing elastomeric material to close the canal formed by the tube and to form a hermetic seal.