Liquid Chromatograph Pressure Estimation Before Sample Filling
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Solution Overview
Problem
Existing liquid chromatograph systems face challenges in predicting the maximum pressure reached during measurement, as they rely on operator experience and indeterminate parameters, leading to potential pressure fluctuations that can stop measurements prematurely.
Innovation Solution
A method for controlling a liquid chromatograph that calculates the maximum pressure presumed during measurement by using a pressure sensor, initial pressure, and known parameters of the flow channel, and prevents sample filling if the maximum pressure exceeds a predetermined limit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If actual measurement is performed to monitor pressure fluctuation, then measurement accuracy is improved, but measurement may stop prematurely when maximum pressure exceeds upper limit
Solution Approach 1:
The patent performs preliminary pressure estimation before actual measurement by calculating the maximum presumed pressure based on initial pressure and gradient liquid feeding conditions. This preliminary action allows the system to predict potential pressure issues and prevent premature measurement stops, thereby improving measurement completion rate while maintaining pressure monitoring accuracy through the estimation mechanism.
2Reliability
If pressure estimation is performed before measurement, then measurement reliability is improved, but system complexity increases
Solution Approach 1:
The control unit utilizes existing system data (initial pressure from pressure sensor and gradient liquid feeding conditions) to perform self-estimation of maximum pressure without requiring additional external measurement devices or complex algorithms. This self-service approach improves measurement reliability through preliminary pressure assessment while minimizing increases in system complexity by leveraging available system resources.
3Ease of operation
If maximum pressure is predicted based on operator experience, then ease of operation is maintained, but prediction accuracy deteriorates
Solution Approach 1:
The patent replaces the mechanical approach of operator experience-based prediction with an automated calculation system. The control unit computes maximum presumed pressure objectively using initial pressure measurements and gradient liquid feeding conditions, eliminating subjective human judgment. This substitution maintains ease of operation as the system executes calculations automatically while dramatically improving pressure prediction accuracy through quantitative analysis.
Data Source
AI summary
A method of controlling a liquid chromatograph that estimates the maximum value of the pressure reached during measurement before actually measuring a sample. The method includes a pump having a gradient function that feeds liquid while changing the composition of a plurality of eluents, according to gradient liquid feeding conditions, a sample filling unit for filling a sample, a separation column, an analysis flow channel connecting the pump to the separation column, and a pressure sensor which detects a pressure within the analysis flow channel during liquid feeding by the pump. A maximum pressure presumed during measurement is calculated based on an initial pressure as a pressure within the analysis flow channel when the pump starts feeding liquid and the gradient liquid feeding conditions and that when the maximum pressure presumed is determined to be a predetermined upper pressure limit, the sample filling is not performed.