Liquid Chromatography Valve Control for Common-Pressure Gradient Flow
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Solution Overview
Problem
High performance liquid chromatography (HPLC) systems face challenges in providing continuous or gradient flow of mobile phases from two pumps with differing compressibilities, requiring additional fluids to account for pressure equalization, which complicates the delivery of mobile phases at a common pressure.
Innovation Solution
A system comprising two pumps, pressure sensors, and a controller that regulates the flow through a valve with specific stator and rotor configurations to ensure communication and pressure matching between the pumps, allowing for continuous or gradient flow of mobile phases at a common pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two pumps with differing compressibilities are used to provide mobile phases, then the system can achieve gradient flow capability, but pressure equalization becomes difficult requiring additional fluids
Solution Approach 1:
Pressure sensors are installed on each pump to monitor pressure levels, and a controller receives these signals to regulate pump operation. This feedback mechanism enables automatic pressure equalization between pumps with different compressibilities, eliminating the need for additional compensating fluids while maintaining gradient flow capability
Solution Approach 2:
The system dynamically adjusts operating parameters (pressure, flow rate) of each pump based on real-time conditions. By changing these parameters through controller regulation, the system achieves pressure equalization between pumps with different compressibilities, resolving the contradiction between gradient flow capability and system complexity
2Productivity
If mobile phases are provided at different pressures from two pumps, then each pump can operate independently, but effective flow through the valve is compromised
Solution Approach 1:
The system equalizes pressure (creates equipotential conditions) between the two pumps before they discharge through the valve. By ensuring both pumps operate at the same pressure level through sensor feedback and controller regulation, the system maintains independent pump operation while ensuring effective and reliable flow through the valve
3Adaptability or versatility
If a valve with multiple positions is used to facilitate flow from two pumps, then flow flexibility is improved, but the complexity of pressure matching increases
Solution Approach 1:
Pressure sensors on each pump provide real-time pressure data to the controller, which regulates pump operation to maintain pressure equality. This feedback control simplifies the pressure matching requirement for the multi-position valve, allowing the valve to achieve flow flexibility without increasing overall system complexity
Data Source
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AI summary
Systems for use with liquid chromatography for provision of continuous flow or gradient flow in connection with two pumps providing mobile phase to a valve.