Syringe Pump Speed Control for Chromatograph Injection Accuracy
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Solution Overview
Problem
In preparative chromatographs, achieving accurate and efficient sample injection into a separation flow path is hindered by the need for a syringe pump to operate at a speed that balances completion of sample intake and filling operations within a set injection interval time, where higher speeds compromise injection accuracy.
Innovation Solution
A preparative chromatograph system that includes a syringe pump with adjustable intake and discharge operation speeds, determined by a pump speed determiner based on the injection interval time, to ensure accurate and efficient sample injection by optimizing the syringe pump's operation speed during sample intake and filling operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the syringe pump operates at a higher speed to complete sample intake and filling operations within a shorter injection interval time, then the productivity of the preparative chromatograph is improved, but the manufacturing precision of the sample injection amount deteriorates
Solution Approach 1:
The syringe pump operates at variable speeds during different phases of the injection cycle. The intake operation uses a first speed while the filling operation uses a second speed that is lower than the first speed. This dynamic speed adjustment allows the system to complete operations within the required interval time while maintaining high precision during the critical filling phase that directly affects injection accuracy.
Solution Approach 2:
The system changes the operational parameter (syringe pump speed) between different operation phases. By setting the filling operation speed to be lower than the intake operation speed, the system optimizes the balance between completing operations within the injection interval time and ensuring accurate sample injection. The controller dynamically adjusts the speed parameter based on the current operation phase.
2Productivity
If the syringe pump always operates at a constant high speed to ensure completion of operations in the shortest injection interval time, then the productivity is improved, but the measurement precision of the sample amount deteriorates
Solution Approach 1:
The system transitions from a constant speed operation to a dynamic speed operation where the syringe pump uses different speeds for different phases. The intake operation uses a higher first speed for efficiency, while the filling operation uses a lower second speed for precision. This dynamic adjustment ensures both productivity and measurement precision are optimized.
Solution Approach 2:
The system performs the intake operation at a higher speed to quickly prepare the sample, then switches to a lower speed for the filling operation to ensure precision. This preliminary high-speed action followed by a precision-focused action allows the system to meet tight injection interval requirements while maintaining accurate injection amounts.
Data Source
AI summary
An injection valve switches between a first state in which a sample loop is connected to a separation flow path through which a mobile phase from a liquid sender flows and a second state in which the sample loop is disconnected from the separation flow path. A pump speed determiner, in a case where a sample intake operation by a syringe pump is started immediately after the injection valve is switched from the second state to the first state, and a filling operation of filling the sample loop with the sample by the syringe pump is started after the intake operation is completed, determines an intake operation speed of the syringe pump that is required in order for the filling operation to complete immediately before the injection valve is switched from the second state to the first state next time using a set injection interval time. The syringe pump operates at the intake operation speed determined by the pump speed determiner while performing the intake operation. The sample is injected by the injector at intervals of the set injection interval time.