Reciprocating Pump Control for Liquid Supply Precision
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Solution Overview
Problem
Reciprocating pumps in liquid chromatography systems face variations in liquid supply, which can lead to incorrect operations, such as incomplete replacement of cleaning liquids, potentially mixing undesired substances with target components during the preparative separation-purification process.
Innovation Solution
A controlling apparatus and method for a reciprocating pump that sets a target liquid supply amount, computes the smallest multiple of the unit discharge amount to ensure consistent liquid supply, and adjusts the motor control to maintain consistent activation timing, preventing variations in liquid supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the pump is activated for a computed time period based on target liquid supply amount and flow rate, then the liquid supply process can be completed within expected time, but the actual liquid supply amount varies due to timing variations in drawing and discharge operations
Solution Approach 1:
The control unit counts the number of reciprocating operations and compares it with the target number of operations calculated from the target liquid supply amount and unit discharge amount. By using feedback control based on the actual counting result, the system adjusts the operating time to ensure the liquid supply amount matches the target value, thereby resolving the contradiction between time efficiency and supply amount precision.
Solution Approach 2:
The patent replaces the traditional mechanical timing method (controlling pump operation time based on flow rate) with an electronic control system that counts reciprocating operations. This substitution allows for more precise control of the liquid supply amount by directly counting discrete pumping cycles rather than relying on continuous time-based flow rate control, thus improving manufacturing precision while maintaining reasonable time efficiency.
2Ease of operation
If the pump operates with simple timing control, then the operation is easy to implement, but the liquid supply amount varies and may be insufficient for correct operation such as cleaning liquid replacement
Solution Approach 1:
The control unit implements feedback control by counting the actual number of reciprocating operations and comparing it with the target number. This feedback mechanism ensures that the liquid supply amount consistently meets or exceeds the target value, thereby improving reliability while maintaining ease of operation through automated control.
Solution Approach 2:
The control unit pre-calculates the target number of reciprocating operations based on the target liquid supply amount and the unit discharge amount stored in memory. By determining the required number of operations in advance, the system ensures reliable liquid supply without requiring complex real-time adjustments, thus maintaining ease of operation while improving consistency.
3Device complexity
If the pump uses fixed flow rate control, then the pump operation is straightforward, but the actual liquid supply amount may differ from the target amount due to variations in drawing and discharge timing
Solution Approach 1:
The patent replaces continuous flow rate control with discrete reciprocating operation counting. The control unit calculates the target number of operations and counts actual operations, substituting the mechanical flow rate control mechanism with an electronic counting system. This approach improves liquid supply amount accuracy while keeping the control system relatively simple through straightforward counting and comparison logic.
Solution Approach 2:
The patent segments the continuous liquid supply process into discrete reciprocating operations. By controlling and counting individual pumping cycles rather than managing continuous flow, the system achieves more precise control over the total liquid supply amount. This segmentation allows for better accuracy while maintaining manageable system complexity through modular operation control.
Data Source
AI summary
A preparative separation-purification system has controlling apparatus, which has a pump housing for pumping liquid. The apparatus also has a moving component for reciprocating in the pump housing so as to draw a liquid into the pump housing and discharge the liquid from the pump housing and a driving source for reciprocating the moving component. A setting unit is provided for setting a target liquid supply amount or a target amount which corresponds thereto. A unit amount memory unit is provided for storing a discharge amount of the reciprocating pump per a reciprocal movement of the moving component or a unit amount which is a value corresponding to the discharge amount. A computation unit is provided for computing the smallest multiple number of the unit amount which is equal to or larger than the target amount; and a motor controller for controlling the driving source.