Drum Dosing Pressure Feedback for Accurate Powder Mass Measurement
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Solution Overview
Problem
Dosing quantities produced by drum dosing devices often exhibit inconsistent ejection behavior due to varying fall speeds and tumbling motions, leading to inaccurate mass measurements and potential faults in the dosing process.
Innovation Solution
A method involving the comparison of actual time periods between ejection and measurement reference points to adjust positive ejection pressure, ensuring consistent dosing behavior and fall speeds by incrementally or proportionally adjusting pressure based on deviations from specified time periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed positive ejection pressure is used to eject dosing quantities from the dosing opening, then the ejection process is simple to control, but the dosing quantities are not ejected uniformly resulting in variations in fall speed and tumbling motions that falsify mass measurement results
Solution Approach 1:
The patent implements feedback control by continuously monitoring the actual time period between ejection and mass verification, comparing it with a specified time period, and adapting the positive ejection pressure accordingly. This closed-loop feedback mechanism ensures uniform ejection and consistent fall speed of dosing quantities, thereby improving mass measurement precision while maintaining manageable control system complexity through automated adjustment.
Solution Approach 2:
The patent dynamically changes the positive ejection pressure parameter based on the comparison between actual and specified time periods. By adjusting this critical parameter in response to measured performance, the system achieves uniform ejection characteristics and consistent dosing quantity delivery, resolving the contradiction between measurement precision and control simplicity.
2Reliability
If the positive ejection pressure is increased to ensure uniform ejection, then the dosing quantities are ejected more consistently, but the risk of over-ejection and process faults increases
Solution Approach 1:
The feedback control mechanism monitors the actual time period and compares it with the specified time period to determine the appropriate positive ejection pressure. This prevents over-ejection by only increasing pressure when the actual time period exceeds the specified value, thereby ensuring ejection uniformity while avoiding process faults associated with excessive pressure application.
Solution Approach 2:
The patent employs dynamic adjustment of the positive ejection pressure rather than using a fixed high pressure. The pressure level is adapted in real-time based on process conditions, allowing the system to maintain reliable uniform ejection while avoiding the harmful effects of consistently high pressure that could cause over-ejection and process faults.
3Measurement precision
If continuous monitoring of mass is performed with an AMV system, then dosing accuracy can be verified, but the dosing process becomes more complex and time-consuming
Solution Approach 1:
The patent implements continuous mass monitoring throughout the dosing process using an AMV system, maintaining constant verification without interrupting the dosing cycle. This continuous action approach ensures dosing accuracy is verified at all times while minimizing time loss by integrating the measurement process into the existing workflow rather than adding separate verification steps.
Solution Approach 2:
The continuous mass monitoring data is immediately fed back into the control system to adjust the positive ejection pressure in real-time. This feedback loop enables the system to maintain accurate dosing while operating efficiently, as the monitoring serves both verification and active control functions simultaneously, reducing the overall time penalty of continuous measurement.
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 enhances the precision of mass determination by maintaining consistent dosing quantity fall speeds and reducing measurement inaccuracies, facilitating extended process monitoring and early response to changes, thereby improving overall dosing accuracy.
Implementation Method 1
the dosing opening being subjected to a negative pressure through the filter element... Under the effect of the negative pressure, powder is drawn into the dosing openings
Implementation Method 2
the dosing opening being subjected to a positive ejection pressure through the filter element and the dosing quantity being thereby ejected
Implementation Method 3
a capacitive measuring device being used... the dosing quantity ejected from the dosing opening falls through a capacitive measuring section of the AMV system and thereby generates a capacitive measuring signal
Data Source
AI summary
A method is for producing individual dosing quantities of a powdered product via a drum dosing device. A dosing drum has a dosing opening on its circumference. In an ejection position, an ejection process is effected, the dosing opening being subjected to a positive pressure and the dosing quantity being thereby ejected from the opening, and an associated ejection reference time-point being determined. The individual mass of an ejected dosing quantity and an associated measurement reference time-point are determined via the measuring device. An actual time period is ascertained from the difference between the measurement reference time-point and the ejection reference time-point and compared with a specified time period. In dependence on the comparison, an adaptation of the positive pressure for a subsequent ejection process is performed such that the level of the positive pressure is increased if the actual time period is too great.