Sectoral Rotor Load Measurement for Anticipatory Flow Compensation
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Solution Overview
Problem
Existing metering systems for flowable materials struggle with inaccuracies due to mass flow fluctuations and inertia, particularly in materials prone to bridging or fluidization, leading to regulation dead time and increased construction costs.
Innovation Solution
A method and apparatus for continuous gravimetric metering using sectoral load measurement to determine instantaneous mass flow, allowing anticipatory control of the metering device speed to compensate for mass flow deviations before delivery, utilizing a metering rotor with sectoral load detection and anticipatory control points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metering rotor with substantial mass (hundreds of kilograms) is used to ensure pressure surge resistance, then reliability is improved, but the ability to compensate for short-term mass flow fluctuations deteriorates due to inertia
Solution Approach 1:
The system performs preliminary action by determining the instantaneous mass flow at an anticipatory control point located ahead of the delivery point. This allows the control system to predict future mass flow deviations before they occur at the delivery point, enabling proactive compensation rather than reactive adjustment. The anticipatory control point is positioned such that its mass flow information can be used to adjust the metering device speed before the actual delivery occurs, effectively looking ahead in the material flow to prevent deviations rather than correct them after they occur.
Solution Approach 2:
The rotor weighing path is divided into multiple sectors, with at least one anticipatory control point located in a sector ahead of the delivery point. This segmentation allows independent measurement and control based on the position of material in different sectors of the rotor, enabling the system to differentiate between material that will be delivered soon versus material that is still in the weighing path. This spatial segmentation resolves the contradiction by allowing the system to use information from the anticipatory sector to control overall delivery while the substantial mass of the rotor continues to provide pressure surge resistance.
2Measurement precision
If a collecting container supported on load cells is added to compensate for mass flow fluctuations, then measurement precision is improved, but device complexity and space requirements increase
Solution Approach 1:
The metering rotor itself is made multi-functional by utilizing its existing substantial mass for both pressure surge resistance and as the measurement medium. The rotor's mass, which would traditionally be seen as a limitation for fast response, is instead leveraged as a built-in buffer that naturally dampens fluctuations while the sectoral load measurement at the anticipatory control point provides the intelligence needed for precise control. This eliminates the need for a separate collecting container, as the rotor performs both the buffering function and the measurement function simultaneously.
Solution Approach 2:
The system uses its own inherent properties - the substantial mass of the metering rotor and the position of material within it - to achieve mass flow fluctuation compensation without requiring external compensating devices. The rotor's own mass and geometry provide the necessary buffering capacity, while the load cell measurement system already present in the device provides the measurement capability. By combining these self-contained resources with anticipatory control logic, the system achieves precise fluctuation compensation without adding external collecting containers or additional space-consuming components.
3Device complexity
If the total rotor weighing path loading is measured, then device complexity is reduced, but measurement precision deteriorates due to non-constant loading distribution over the rotor weighing path
Solution Approach 1:
Instead of measuring the total loading uniformly across the entire rotor weighing path, the system applies local quality measurement by focusing the load cell measurement on a specific sector - the anticipatory control point sector - which is located ahead of the delivery point. This localized measurement captures the loading distribution characteristics at a specific position in the rotor, providing precise information about material that will be delivered in the near future. The load cell is positioned to measure only the sector corresponding to the anticipatory control point, giving localized loading information rather than an averaged total.
Solution Approach 2:
The system performs preliminary measurement action by positioning the load cell to measure the loading at the anticipatory control point sector before the material reaches the delivery point. This preliminary measurement of the specific sector's loading allows the control system to predict and compensate for upcoming mass flow deviations. By measuring the loading distribution at the anticipatory position rather than averaging the total, the system gains early warning information about future delivery conditions while maintaining relatively simple device architecture.
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
Achieves high short-term metering accuracy by accurately predicting and adjusting for mass flow fluctuations, minimizing regulation dead time and reducing construction complexity.
Implementation Method 1
a metering rotor balance according to DE 3217406 A1 or EP A 0 198956 is utilized... the weighing signal of the hopper weighing cells serves as an input signal... the bulk goods mass acting instantaneously in the rotor weighing path in the metering rotor balance is detected
Data Source
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AI summary
The invention relates to a method for continuous, gravimetric metering and mass flow determination of flowable materials, comprising: determining with a metering device an instantaneous mass flow at an anticipatory control point located a first distance ahead of a delivery point for the flowable material; affecting discharge of the flowable material by altering a speed of rotation of the metering device and varying the first distance of the anticipatory control point ahead of the delivery point depending on at least one of a current actual speed and a loading of the metering device, wherein the loading of the metering device is calculated on the basis of a sectoral load measurement.