Dual Pump Dosing Control via Piston Reversal
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Solution Overview
Problem
Existing dosing and mixing systems experience inefficiencies due to dead time during pump reversal and waiting periods, leading to flow rate fluctuations and potential imbalances between pump circuits, which affect the consistency of the mixture delivery.
Innovation Solution
A control method that continuously determines the remaining volume in each pump and reverses the piston movement during the injection of the other component to maintain continuous operation, using a controller connected to displacement detectors to ensure sufficient volume for the next dose and detect leaks, thereby minimizing downtime and pressure drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the piston displacement is reversed using an end stop to complete the sequential injection cycle, then the injection process can be completed, but dead time is created during pump reversal and waiting periods, reducing system efficiency
Solution Approach 1:
The controller determines the remaining volume in the pump before the piston reaches the end stop position. When insufficient volume is detected, the controller triggers piston reversal in advance during the injection phase of the other pump, rather than waiting for the end stop to activate reversal. This preliminary action eliminates dead time by ensuring the pump is ready for the next injection cycle without waiting periods.
2Productivity
If the piston is reversed during the injection of the other component to eliminate dead time, then operational efficiency is improved, but differential pressure may occur between pump circuits, causing flow rate fluctuations
Solution Approach 1:
The system continuously monitors the position of both pistons and the state of injection valves through displacement detectors. The controller uses this feedback information to determine remaining volumes and coordinate piston reversals. By basing reversal decisions on actual measured positions and volumes rather than fixed timing, the system maintains pressure balance between circuits while eliminating dead time, preventing flow rate fluctuations.
3Productivity
If the remaining volume in the pump is not monitored, then the system operates with simpler control, but the pump may not have sufficient volume for the next dose, interrupting continuous operation
Solution Approach 1:
The system replaces complex mechanical volume measurement mechanisms with an electronic control system that calculates remaining volume based on piston displacement detected by displacement detectors. The controller determines remaining volume by tracking the piston position from the last reversal point to the current position, eliminating the need for mechanical volume sensors while ensuring sufficient volume for continuous operation.
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The method involves determining remaining volumes in respective double action reciprocating pumps (1, 2) when injection valves of the corresponding pumps are closed, where same pressure is maintained in the pumps. Displacement of a piston of the pump (1) is reversed in a suction and expulsion direction of a component i.e. base, while the injection valve of the pump (2) is opened to inject a dose of another component i.e. catalyst, in a mixer (3), if the remaining volume of the pump (1) is insufficient to inject a dose following to the injection of a predefined dose. An independent claim is also included for a controlled dosage and mixing system for dosing and mixing a product composed of two components.