Positive Displacement Pump Dosing Profiles With Model-Based Control
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Solution Overview
Problem
Magnetic metering pumps face challenges in controlling movement for low metering speeds, especially when abrupt fluid delivery is not desired, and existing control methods are complex and unsuitable for handling unexpected faults or changes in fluid conditions like cavitation or viscosity variations.
Innovation Solution
A model-based control method is developed, using a state space model to predict system behavior and calculate necessary manipulated variables, allowing for adaptive control without prior tabulation of control parameters, and incorporating self-learning mechanisms to correct deviations in fluid pressure and flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the electromagnet is activated to move the diaphragm from the second position to the first position, then the metering rate is improved, but the movement becomes abrupt which is undesirable for low metering speeds
Solution Approach 1:
The patent applies dynamics by making the electromagnet's current profile adjustable and time-dependent. Instead of a fixed abrupt activation, the current can be modulated to create gradual or stepped movement profiles, allowing the system to adapt its dynamic behavior to different metering speed requirements and maintain control quality across various operating conditions.
Solution Approach 2:
The patent changes the parameter of electromagnet current from a simple binary on/off state to a controllable variable with multiple possible profiles (gradual, stepped, etc.). This parameter change enables the system to optimize both metering rate and movement control quality by selecting appropriate current profiles for different operating conditions.
2Manufacturing precision
If different control parameters are empirically determined and stored in memory for different pressure piece position states, then the control accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent uses feedback from the position sensor to continuously monitor the pressure piece position and automatically select or adjust the appropriate current profile from available options. This feedback mechanism maintains high control accuracy across different position states without requiring complex manual configuration or multiple dedicated control systems for each state.
Solution Approach 2:
The patent creates a universal control system that can handle multiple pressure piece position states using a single integrated controller with programmable current profiles. Instead of requiring separate control circuits for each position state, one multi-functional controller adapts its behavior based on real-time position feedback, reducing overall system complexity.
3Loss of time
If the control parameters are stored in memory for retrieval based on pressure piece position, then the response time is improved, but the adaptability to unexpected conditions like cavitation or viscosity changes decreases
Solution Approach 1:
The patent makes the control system dynamic by allowing real-time switching and blending of different current profiles based on position feedback and detected operating conditions. Instead of relying on a single static lookup table, the system can adaptively combine multiple profiles or select from various pre-programmed profiles to respond to unexpected conditions like cavitation or viscosity changes while maintaining fast response times.
Solution Approach 2:
The patent enhances feedback by monitoring not only position but also operating conditions such as fluid viscosity and cavitation indicators. This expanded feedback enables the controller to detect unexpected conditions and adjust the current profile selection or parameters in real-time, maintaining both fast response and high adaptability to varying fluid conditions.
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
This approach provides improved control quality and accuracy, enabling precise regulation of fluid flow even under unexpected conditions, such as cavitation or changes in fluid viscosity, without the need for additional sensors, thus enhancing the reliability of magnetic metering pumps.
Implementation Method 1
If a current is applied to the electromagnet, a magnetic flux is formed, which moves the correspondingly designed pressure piece inside the electromagnet from its second position to the first position
Implementation Method 2
As long as the electromagnet is not carrying a current, so that no magnetic flux is generated inside it, the spring tension ensures that the pressure piece, and thus the diaphragm, remains in a predetermined position
Data Source
AI summary
The invention relates to a method for optimizing metering profiles of displacement pumps in which a movable displacement element bounds a metering chamber, which metering chamber is connected to a suction line and to a pressure line by means of valves, such that pumped fluid can be alternately sucked into the metering chamber via the suction line and pressed out of the metering chamber via the pressure line by means of an oscillating movement of the displacement element, wherein a drive is provided for the oscillating movement of the displacement element. In order to provide a method according to the invention which permits control of the pressure-piece movement without prior tabulation of control parameters even if the system is exposed to unexpected disturbances, a model-based control according to the invention is used for the drive.