NMR Sample Tube Closure With Compliant Interference Fit
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Solution Overview
Problem
NMR spectrometers face resolution issues due to sample tube asymmetries and inconsistent closure systems, leading to potential sample loss and delays in expensive studies, as existing closure devices are not reliable or compatible with automated handling systems.
Innovation Solution
A selectively removable closure system for NMR sample tubes with a cylindrical design featuring a hollow bore with distinct sections for a compliant interference fit, ensuring secure sealing and easy handling, independent of the tube's top end, and compatible with automated systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional closure device is used to close the NMR sample tube, then the tube can be sealed, but the closure may not provide consistent alignment and sealing, leading to sample loss and degraded spectrum quality
Solution Approach 1:
The closure device incorporates a sealing bead at the distal end that provides localized sealing contact with the sample tube. This concentrated sealing mechanism ensures reliable sealing without requiring perfect alignment across the entire closure-tube interface, resolving the contradiction between sealing reliability and alignment consistency.
Solution Approach 2:
The sealing bead acts as an intermediary element between the closure body and the sample tube. It provides a compliant sealing interface that can accommodate minor misalignments while maintaining reliable sealing, thus improving both sealing reliability and ease of operation.
2Device complexity
If the closure system depends on the tube's top end for sealing, then the sealing mechanism is simple, but it is vulnerable to chip damage and inconsistent tube ends
Solution Approach 1:
The sealing function is extracted from the tube's top end and relocated to a sealing bead on the closure device. This separates the sealing mechanism from the tube's potentially defective top end, making the system reliable while maintaining relatively simple device complexity.
Solution Approach 2:
The sealing bead provides a compliant sealing interface that anticipates and compensates for potential damage or inconsistency at the tube's top end. By positioning the sealing contact point on the closure rather than relying on the tube end, the system pre-cushions against the harmful effects of chip damage.
3Adaptability or versatility
If existing closure devices are used, then they can close the tube, but they are not compatible with automated sample handling equipment
Solution Approach 1:
The closure device is designed with a standardized geometry and sealing mechanism that serves multiple functions: manual handling, automated robotic gripper compatibility, and reliable sealing. This universal design approach enables automated system compatibility without significantly increasing device complexity.
4Reliability
If the closure provides secure sealing, then sample loss is prevented, but the closure may be difficult to remove or install
Solution Approach 1:
The sealing bead provides a dynamic sealing mechanism that requires minimal insertion force while maintaining secure sealing once installed. The compliant nature of the sealing bead allows for easy installation and removal while preventing sample loss, resolving the contradiction between sealing security and installation ease.
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 closure system provides a secure, user-friendly, and reliable means to handle NMR sample tubes, minimizing sample loss and optimizing spectrometer resolution by maintaining a consistent seal and alignment, even with imperfect tube ends, and is compatible with automated handling systems.
Implementation Method 1
The central section is sized to provide a compliant interference fit with the outside diameter of the preselected size NMR sample tube
Data Source
AI summary
A removable closure for closing the open end of an NMR sample tube having an open end and a closed end of the invention includes a cylindrical proximal first and a distal second portion, both portions substantially congruent to a central axis. The second portion has a hollow bore extending therethrough, the hollow bore has three sections: a distal section, a central section and a proximal section. The distal section has an inside diameter sized to accept the outside diameter of a preselected size NMR sample tube substantially without an interference, the central section is sized to provide a compliant interference fit with the outside diameter of the preselected size NMR sample tube, and the proximal section is sized to accept the outside diameter of the preselected size NMR sample tube without interference.