Carousel Scale Calibration Using Reference Weight Sector
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Solution Overview
Problem
Carousel scales generate dynamic weight values due to rotational movement, which are not precise enough for high-precision measurements, especially in applications like the pharmaceutical industry, as they include vibrations and centrifugal forces affecting the weighing sensors.
Innovation Solution
A calibration sector is introduced between the unloading and loading sectors where load cells are loaded with a reference weight to determine dynamic reference weight values, which are then compared to known static reference weights to calculate precise correction values for dynamic sample weight values, reducing deviations between static and dynamic weights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carousel scale operates with continuously rotating base to enable high-speed weighing of multiple goods, then productivity is improved, but measurement precision deteriorates due to dynamic forces affecting load cells
Solution Approach 1:
The patent applies preliminary action by performing calibration of the carousel scale before actual weighing operations. A calibration phase is executed where the system determines correction values for each load cell position while stationary, which are then stored and applied during subsequent dynamic weighing operations to compensate for the effects of rotation and centrifugal forces
Solution Approach 2:
The patent applies parameter changes by introducing correction values that are added to the raw measurement signals from the load cells. These correction values compensate for the dynamic forces (centrifugal force, vibration) that vary with rotational speed and position, effectively changing the measurement parameters to account for the rotating reference frame
2Device complexity
If correction values are determined using only empty carousel scale calibration, then device complexity is reduced, but measurement precision is insufficient for high-precision applications
Solution Approach 1:
The patent applies segmentation by dividing the calibration process into multiple distinct phases: an initial empty-scale calibration phase and a subsequent loaded calibration phase. Each phase addresses different aspects of the measurement error, with the empty scale calibration handling baseline offsets and the loaded calibration handling dynamic force effects, allowing comprehensive correction without excessive complexity
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 method significantly improves the accuracy of weight measurements by accounting for centrifugal forces and other parasitic forces, ensuring more precise correction values and reducing errors, thus enhancing the precision of dynamic weight values to match static weights.
Implementation Method 1
each load cell has a load receptacle that can be loaded with the goods to be weighed and that is (typically) connected to a mechatronic weighing system via a lever mechanism
Implementation Method 2
those sample weight values are sought that would result from weighing with a stationary load cell, although a carousel scale is, in principle, only capable of supplying dynamic sample weight values recorded with moving load cells. In addition to the pure sample weight, vibration and above all centrifugal forces also contribute to these dynamic sample weight values
Data Source
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AI summary
The invention relates to a method for operating a carousel scale (10, 10') with a plurality of load cells (12) arranged in a ring on a continuously rotating base and moved on a circular path divided into several functional sectors (I, II, III, IV, V), wherein - the load cells (12) are loaded with a sample (100; 104) to be weighed in a loading sector (I), - corresponding dynamic sample weight values are determined in a weighing sector (II), - the dynamic sample weight values are corrected with the correction values assigned to the load cells (12), and - the samples (100; 104) are removed from the load cells in an unloading sector (III).The invention is characterized in that in a calibration sector (IV) located in the direction of rotation behind the unloading sector (III) and in front of the loading sector (I) - the load cells (12) are loaded with a reference weight (20) of known static reference weight, - corresponding dynamic reference weight values are determined, and - the correction values are calculated by comparing the determined dynamic reference weight values with the known static reference weights.