Adaptive Mass Flow Control for Filling Free-Flowing Substances
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Solution Overview
Problem
Existing methods for accurately and rapidly dispensing small quantities of free-flowing substances into target containers are inefficient due to reliance on volumetric measurements, which are influenced by complex rheological properties and result in contamination and prolonged filling times, especially when dealing with pulverous substances.
Innovation Solution
A method and apparatus that utilize a valve with adjustable mass flow rate controlled by a controller unit, incorporating an adaptive filter and weighing signal processing to maintain a desired mass flow rate, ensuring accurate and reproducible filling within a predetermined tolerance, suitable for both pulverous and liquid substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If volumetric measurement methods are used to control the amount of substance delivered, then the filling process can be performed, but the mass accuracy deteriorates due to complex rheological properties and influence factors
Solution Approach 1:
The patent implements a feedback control system where the actual mass flow rate (determined from balance measurements) is continuously compared with the desired mass flow rate, and the valve aperture is adjusted accordingly to maintain accurate mass delivery. This closed-loop feedback mechanism resolves the contradiction by enabling fast filling while maintaining precision through real-time correction of flow rate deviations.
Solution Approach 2:
The patent replaces volumetric measurement methods with mass flow rate control based on balance measurements. Instead of relying on mechanical volumetric dispensing which is affected by rheological properties, the system uses gravitational mass flow control where the force of gravity acting on the substance is measured and controlled, eliminating the influence of complex rheological behavior on measurement accuracy.
2Manufacturing precision
If optimization extends over several filling cycles, then the mass flow can be optimized, but the filling time increases and substance may be contaminated
Solution Approach 1:
The patent performs preliminary calibration of the balance and determination of the delay interval before the actual filling process. By pre-characterizing the system response and storing calibration data, the system eliminates the need for trial-and-error optimization during production cycles, enabling immediate accurate filling without time loss and preventing contamination of test substances.
Solution Approach 2:
The system uses its own balance measurements to automatically adjust and optimize the mass flow rate in real-time during filling, rather than requiring external optimization processes. The controller unit self-regulates the valve aperture based on feedback from the balance, making the system self-optimizing and eliminating the need for separate optimization cycles that would consume time and risk contaminating substances.
3Measurement precision
If the balance response time is considered, then accurate mass measurement is possible, but the filling speed must be reduced to allow sufficient response time
Solution Approach 1:
The patent determines and stores the delay interval parameter beforehand through calibration, accounting for the balance's response time characteristics. By pre-compensating for this time delay in the control algorithm, the system can operate at high filling speeds without sacrificing measurement accuracy, as the controller already knows how much time the balance needs to respond before providing accurate feedback.
Solution Approach 2:
The patent implements dynamic adjustment of the desired mass flow rate based on real-time balance feedback, continuously adapting to the actual flow conditions. The controller dynamically modifies the valve aperture position in response to measured mass flow deviations, enabling the system to maintain both high speed and high precision by constantly optimizing the flow rate within the balance's response capabilities.
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
Enables fast and accurate dispensing of small quantities of free-flowing substances, minimizing contamination risks and reducing filling time by dynamically adjusting the mass flow rate based on real-time weighing and environmental factors, ensuring precise target mass delivery.
Implementation Method 1
a balance for determining the mass m of the substance in the target container
Implementation Method 2
the hydrostatic pressure resulting from the fill height h of the substance in the reservoir
Data Source
AI summary
A container is filled to a predetermined target mass of a free-flowing substance with the help of a device that dispenses measured doses of the substance. The dispensing device has a valve for variably adjusting the mass flow rate of the substance from a reservoir into the container. The dispensing device further includes a device to measure the elapsed time from the beginning of the filling process, a balance for determining the mass of the substance in the container, and a controller unit with a valve control module. The controller unit includes an adjusting module, where a predetermined desired mass flow rate is stored. At an elapsed time, if the mass flow rate is smaller or larger than the desired mass flow rate, the flow rate is, respectively, increased or decreased by a flow rate adjustment. An adaptive filter of the controller unit determines the mass flow rate.