Autosampler Pressure Release Mechanism for Liquid Chromatograph Contamination
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Solution Overview
Problem
The existing autosampler for liquid chromatographs faces contamination issues due to the ejection of mobile phase from the needle tip when the needle is pulled out of the injection port, leading to device contamination.
Innovation Solution
Incorporating a pressure release operation unit that controls the needle drive and switching mechanisms to transition the sampling channel from a closed system to an open system before the needle is pulled out, ensuring the pressure inside the sampling channel returns to atmospheric pressure, thereby preventing mobile phase ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the needle is pulled out from the injection port immediately after the sampling channel is disposed between the feeding device and the analytical column, then the operation time is reduced, but the mobile phase is ejected from the needle tip causing contamination
Solution Approach 1:
The switching mechanism performs a preliminary action by switching the sampling channel out of the high-pressure path before the needle is pulled out from the injection port. This preliminary switching prevents the compressed mobile phase from being ejected when the needle is removed, thereby avoiding contamination while maintaining efficient operation timing.
2Ease of operation
If the switching mechanism switches the sampling channel to be disposed between the feeding device and the analytical column, then the sample introduction function is improved, but the pressure inside the sampling channel increases causing potential ejection
Solution Approach 1:
The switching mechanism dynamically changes the configuration of the sampling channel, alternating between being disposed between the feeding device and analytical column (for sample introduction) and being disposed elsewhere (for pressure release). This dynamic switching allows the system to achieve both efficient sample introduction and pressure management.
3Object-affected harmful factors
If the needle is kept inserted in the injection port longer to allow pressure release, then contamination is prevented, but the productivity is reduced
Solution Approach 1:
The switching mechanism performs a preliminary switch to remove the sampling channel from the high-pressure path before the needle is pulled out. This preliminary action enables rapid pressure release without requiring extended waiting time, thus preventing contamination while maintaining high productivity and analysis efficiency.
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 solution effectively prevents mobile phase ejection from the needle tip, reducing contamination risks and enhancing analysis efficiency by optimizing the pressure release time based on the preceding feed pressure.
Implementation Method 1
performing standby until a pressure inside the sampling channel is returned to atmospheric pressure
Data Source
AI summary
An autosampler includes a pressure release operation unit for performing, by controlling operation of a needle drive mechanism and a switching mechanism, before a tip end of a needle is pulled out from an injection port following a state where a sampling channel is disposed between a feeding device and an analytical column, a pressure release operation of switching the switching mechanism in such a way that the sampling channel is not disposed between the feeding device and the analytical column and a system including the sampling channel is made an open system, and of performing standby until a pressure inside the sampling channel is returned to atmospheric pressure.