Capacitive Dosing Calibration for Pharmaceutical Mass Accuracy
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Solution Overview
Problem
In the pharmaceutical sector, achieving precise and repeatable dosing of solid pharmaceutical dosage units is challenging due to density fluctuations and high movement speeds in industrial-scale dosing, making 100% in-process control difficult and expensive.
Innovation Solution
A capacitive measuring system is calibrated using a test body with known dielectric properties, moved back and forth through the measuring channel, allowing for accurate mass determination of dosage units during regular operation, enabling dynamic and precise mass measurement without slowing down the dosing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gravimetric measurements are used to control dosing result, then measurement accuracy is improved, but measurement time increases and productivity decreases
Solution Approach 1:
The patent replaces the mechanical gravimetric weighing system with a capacitive measurement system. The capacitive sensor measures dosing results through electrical fields without requiring physical contact or stopping the dosing process, thereby maintaining high measurement accuracy while preserving production speed. The capacitive measurement takes place during the dosing process itself, eliminating the need for separate weighing steps.
2Measurement precision
If static weighing is used for gravimetric measurements, then measurement accuracy is improved, but the process requires stopping movement and time increases
Solution Approach 1:
The patent transitions from static weighing to dynamic capacitive measurement. The capacitive sensor can measure the dosing result while the dosage unit is still in motion through the dosing channel, eliminating the need to stop the dosing process for measurement. This dynamic measurement approach maintains accuracy while dramatically reducing measurement time and enabling continuous operation.
3Reliability
If 100% in-process control is implemented, then dosing reliability is improved, but device complexity and cost increase
Solution Approach 1:
The capacitive measurement system is integrated directly into the dosing device structure, allowing the dosing device to perform self-measurement and self-control during the dosing process. The capacitive sensor utilizes the electrical properties of the material being dosed to automatically determine dosing accuracy, eliminating the need for separate complex measurement equipment and enabling 100% in-process control with minimal additional 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 approach achieves measurement results with standard deviations of <0.5%, ensuring reliability and accuracy for 100% in-process control, meeting pharmaceutical sector approval requirements, and allowing for dynamic mass determination without static weighing.
Implementation Method 1
a capacitive measuring system (1) comprising a base body (10) with at least one measuring channel (8) formed in it, aligned in the direction of the force of gravity, in which there is arranged the measuring section of a capacitive measuring transducer (14)
Implementation Method 2
The test body, which has previously determined and known dielectric properties, is now moved back and forth along the guide path between the two end positions at least once, preferably several times
Data Source
Figure 1~2
AI summary
The invention relates to a calibration device (2) for a capacitive measuring system (1) in a dosing device, or a dosing device for, in particular, solid pharmaceutical dosage units (9), and an associated dosing method. The calibration device (2) comprises a test object (3), drive means (4) for the test object (3), and a guide (5) for the test object (3) with a first end position (6), a second end position (7), and a guide path (s) extending between the two end positions (6, 7), wherein the drive means (4) are designed to move the test object (3) back and forth along the guide path (s) between the two end positions (6, 7). The capacitive measuring system (1) is calibrated by means of the calibration device (2).The dosage units (9) are then dosed by means of the dosing device and checked for properly dosed mass by means of the calibrated capacitive measuring system (1).