Solvent Supply Piston Control for Flow Rate Accuracy
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Solution Overview
Problem
Existing solvent supply systems face challenges in maintaining precise solvent flow rates due to pressure variations, leading to inaccuracies in solvent composition and oscillations, especially in high-throughput applications and sample analysis.
Innovation Solution
A solvent supply system with a control unit that adjusts piston movement in response to pressure variations, compensating for volumetric changes caused by pressure fluctuations, ensuring a consistent flow rate and stable solvent composition by superposing corrective movements on the piston movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the solvent pressure is increased to improve throughput, then the productivity increases, but the solvent volume in the supply flow path varies due to compression, causing flow rate inaccuracies
Solution Approach 1:
The control unit continuously monitors solvent pressure and uses this feedback to calculate and apply corrective piston movements. The control unit determines the actual pressure in the supply flow path, calculates the required correction based on the pressure-induced volume variation, and adjusts the piston movement accordingly to maintain accurate flow rate despite pressure changes during high-throughput operation
Solution Approach 2:
The system dynamically changes the piston movement parameters (displacement, velocity) based on the measured pressure conditions. When pressure increases causing compression, the control unit adjusts the piston to move further or faster to compensate for the reduced solvent volume, thereby maintaining the desired flow rate accuracy across varying pressure conditions
2Manufacturing precision
If the piston movement is increased to maintain flow rate during pressure rise, then the flow rate accuracy improves, but the system complexity increases due to additional control mechanisms
Solution Approach 1:
The patent replaces complex mechanical flow control mechanisms with a control unit that uses pressure measurements and calculations to determine corrective movements. Instead of complex mechanical feedback linkages, the system uses electronic sensing and computational control to achieve the same flow rate accuracy, simplifying the mechanical structure while maintaining precision
Solution Approach 2:
The control unit acts as an intermediary between the pressure sensor and the piston mechanism. It receives pressure data, calculates the required correction based on known supply flow path characteristics, and translates this into appropriate piston movement commands, thereby decoupling the pressure sensing and flow control functions while maintaining accuracy
3Manufacturing precision
If the supply flow path volume is reduced to minimize pressure variation effects, then the flow rate accuracy improves, but the ability to handle high throughput applications decreases
Solution Approach 1:
The control unit continuously monitors pressure and dynamically adjusts piston movement to compensate for volume effects. This feedback mechanism allows the system to maintain accurate flow rate control even with larger supply flow path volumes that can handle high throughput requirements, eliminating the need to reduce system volume to achieve accuracy
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 system delivers a highly accurate solvent flow that is independent of pressure variations, improving measurement precision and stability, particularly in applications like liquid chromatography where precise solvent gradients are crucial.
Implementation Method 1
a variation of the solvent pressure gives a rise to a corresponding variation of a solvent volume contained in the supply flow path or a part thereof
Data Source
AI summary
A supply flow path for supplying a solvent is described. The supply flow path includes metering devices each with a piston, the metering devices being adapted for metering the solvent through separate source paths feeding the supply flow path. The supply flow path further includes a control unit adapted for controlling the metering devices' piston movement in accordance with solvent pressure, wherein a variation of the solvent pressure gives rise to a corresponding variation of a solvent volume contained in the supply flow path or a part thereof. The control unit is adapted for compensating for the variation of the solvent volume by corresponding movements or forward or backward displacements of the pistons.