Filling Valve Control Using Virtual Pressure for Flow Stability
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Solution Overview
Problem
Existing filling machines for pourable food products in composite packages face challenges in reacting to product line disturbances without the installation of a pressure sensor, due to physical or economic constraints, limiting their ability to adjust the flow regulating valve effectively.
Innovation Solution
A control system that uses a virtual pressure estimation, based on the output of the flow feedback control loop and a reference pressure, to adjust the flow regulating valve, eliminating the need for a dedicated pressure sensor and allowing for improved reaction to flow and pressure fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure sensor is installed to measure inlet pressure for flow regulation, then the ability to react to product line disturbances is improved, but the device complexity and cost increase
Solution Approach 1:
The patent creates a virtual copy of the pressure measurement function through software calculation rather than physical sensing. The control unit computes a virtual pressure value based on the relationship between flow set point and actual flow measurement, replicating the information a pressure sensor would provide without the physical hardware. This allows the system to react to pressure disturbances using the same control algorithms as if a real pressure sensor were installed.
Solution Approach 2:
The patent replaces the mechanical/physical pressure sensor system with an electronic/software-based virtual pressure calculation system. Instead of using a physical device to measure pressure, the control unit calculates virtual pressure from flow measurements and control set points, substituting a complex physical measurement system with a simpler computational approach that achieves the same control objective.
2Manufacturing precision
If a pressure sensor is installed to measure inlet pressure, then the flow regulation accuracy is improved, but the manufacturing cost increases
Solution Approach 1:
The patent creates a virtual copy of the pressure measurement function through software calculation rather than physical sensing. The control unit computes a virtual pressure value based on the relationship between flow set point and actual flow measurement, replicating the information a pressure sensor would provide without the physical hardware. This allows the system to react to pressure disturbances using the same control algorithms as if a real pressure sensor were installed.
Solution Approach 2:
The patent uses inexpensive computational resources within the existing control unit to perform virtual pressure calculations, replacing the need for expensive pressure sensing hardware. The virtual pressure calculation leverages already-available data (flow measurements and control set points) through simple mathematical relationships, providing accurate flow regulation at minimal additional cost.
3Device complexity
If virtual pressure estimation is used instead of a pressure sensor, then the device complexity is reduced, but the measurement precision may be affected
Solution Approach 1:
The patent uses feedback from the actual flow measurement and flow set point to continuously update and refine the virtual pressure estimation. The control system monitors the difference between desired and actual flow, and uses this feedback information to adjust the virtual pressure calculation, ensuring that the estimated pressure accurately reflects the actual system conditions and maintains measurement precision without physical sensors.
Solution Approach 2:
The patent replaces the mechanical/physical pressure sensor system with an electronic/software-based virtual pressure calculation system. Instead of using a physical device to measure pressure, the control unit calculates virtual pressure from flow measurements and control set points, substituting a complex physical measurement system with a simpler computational approach that achieves the same control objective.
Data Source
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AI summary
A method for controlling a flow regulating valve (6) of a filling machine (1) forming composite packages (2) from a multilayer composite packaging material and filling the composite packages with a pourable filling product, wherein a position of the regulating valve controls the flow of the product filling the packages, the method envisages: implementing a flow feedback control, receiving a flow set point (FSP) and an inlet flow measurement (FIN) and generating a feedback control contribution (CFB) indicative of a difference between the inlet flow measurement and the flow set point; implementing a flow feed-forward control, receiving the flow set point (FSP) and generating a feedforward control contribution (CFF) using fluid-dynamic maps, which map an output position of the regulating valve with respect to flow and pressure values of the filling product; generating a virtual pressure (Pv) based on the feedback control contribution (CFB) generated at the output of the flow feedback control module, wherein the flow feedforward control receives the virtual pressure (Pv) and generates at its output the feedforward control contribution (CFF) based on the flow set point (FSP) and the virtual pressure (PV) using the fluid-dynamic maps. The feedforward control contribution (CFF) determines a control signal (Sc) for adjusting an operating position of the flow regulating valve (6).