Fluidic Valve Switching for High-Pressure Sample Injection
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Solution Overview
Problem
Conventional injectors in liquid chromatography systems are limited in their functionality, particularly in terms of flexibility and precision in injecting fluidic samples into high-pressure flow paths.
Innovation Solution
The development of an injector system that includes a sample accommodation volume, a sample drive for intaking the sample, and a fluidic valve switchable between multiple states to selectively couple or decouple the sample accommodation volume with the flow path, allowing for precise control of pressure and flow rates during injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional injector is used to inject samples into high-pressure flow paths, then the injection can be performed, but the functionality and precision are limited
Solution Approach 1:
The injector is divided into functionally independent modules: a sample introduction module with sample loop and valve for precise sample dosing, a high-pressure pump module for mobile phase delivery, and a control module. This segmentation allows each module to be optimized for its specific function while maintaining overall system versatility without excessive complexity
Solution Approach 2:
The injector system is designed with multi-functional capabilities: the same basic structure supports both low-pressure sample loading and high-pressure injection, the valve system can switch between different flow paths for sample introduction, washing, and injection, and the control system can manage various injection modes (manual, automated, triggered). This universality increases adaptability without proportionally increasing device complexity
2Measurement precision
If pressure control is not implemented during injection, then the system is simpler, but the injection precision and reproducibility deteriorate
Solution Approach 1:
A pressure sensor is integrated into the system to monitor the actual pressure in the flow path during injection. This pressure information is fed back to the control unit, which automatically adjusts the high-pressure pump or sample drive to maintain the desired pressure level. This feedback mechanism ensures precise and reproducible injection without requiring overly complex manual pressure control systems
Solution Approach 2:
The system replaces manual mechanical pressure adjustment with an automated electromechanical system. The high-pressure pump and sample drive are controlled by an electronic control unit that can precisely regulate pressure based on programmed parameters or real-time feedback, eliminating the need for complex manual pressure balancing mechanisms while improving precision
3Ease of operation
If the sample accommodation volume is constantly connected to the flow path, then the system is simpler, but the ability to control flow rates and pressures during injection is lost
Solution Approach 1:
The sample is loaded into the sample loop under low pressure or with the flow path disconnected before injection. The valve is positioned to isolate the sample loop from the high-pressure flow path during the sample loading and preparation phase. When injection is required, the valve switches to connect the sample loop to the flow path. This preliminary action allows easy operation during sample preparation while enabling precise flow control during injection, without requiring a permanently complex valve system
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 injector system enables reproducible and precise sample injection, even at high pressures, by fluidically coupling the fluid drive, separation unit, and sample drive, and allows for flexible operation modes to adjust injection procedures according to specific applications.
Implementation Method 1
a rotor valve (95) being switchable between multiple switching states so as to selectively establish a fluidic coupling between the fluid drive (20), the sample drive (102) and the separation unit (30)
Data Source
AI summary
An injector, for injecting a fluidic sample into a flow path between a fluid drive and a sample separation unit, includes a sample accommodation volume, a sample drive, and a fluidic valve switchable to selectively couple the volume with the flow path or decouple the volume from the flow path. In an injection switching state, the fluid drive, the separation unit and the sample drive are coupled by the valve so that fluid driven by the sample drive and flowing from the volume to the separation unit and further fluid driven by the fluid drive and flowing from the fluid drive to the separation unit are combined at a fluidic connection upstream of the separation unit. A control unit controls an outlet flow rate value according to which a combination of the mobile phase and the fluidic sample is driven through the separation unit.