Packaging Machine Filling Box Differential Weighing Control
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Solution Overview
Problem
Existing packaging machines for filling open-mouth bags face limitations in filling capacity and weight precision, especially when handling dusty, fine-grain products, due to issues with air entrapment and vibration interference with weighing systems.
Innovation Solution
A packaging machine design featuring a non-communicating filling box with a separate weighing device and control system that allows for precise differential weighing and concurrent compaction, enabling high filling rates and accuracy by controlling the volume flow and fill height during the filling process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a packaging machine uses a traditional weighing system with vibrating compaction devices, then compaction can be performed during filling, but the vibrations are transmitted to the scales causing incorrect weight measurements
Solution Approach 1:
The system divides the filling process into distinct phases: a first filling phase where the compaction device operates simultaneously with filling (achieving both compaction and high filling rate), and a second filling phase where only filling occurs without compaction vibrations. This segmentation allows the machine to optimize for both productivity and measurement accuracy at different times during the filling process.
Solution Approach 2:
The control device periodically switches between different filling modes - alternating between phases with compaction and phases without compaction. This periodic action allows the system to achieve effective compaction over time while ensuring accurate weight measurements during the non-compaction phases, thus resolving the contradiction between productivity and reliability.
2Productivity
If a packaging machine fills fine-grain products quickly, then filling rate increases, but air becomes trapped reducing stacking capability
Solution Approach 1:
The filling process is segmented into multiple phases with different characteristics. The first phase allows rapid filling to achieve high productivity, while subsequent phases incorporate compaction to remove trapped air and achieve proper package density. This segmentation enables the system to address both productivity and manufacturing precision requirements.
Solution Approach 2:
The system performs preliminary rapid filling to quickly fill the bag, then follows with compaction action to remove air. This preliminary action approach allows the machine to achieve high initial filling rates while subsequently correcting the air entrapment issue that would otherwise reduce stacking capability.
3Productivity
If differential weighing devices are used to increase filling rate, then more devices are required, but inaccuracies of multiple devices may add up reducing weight precision
Solution Approach 1:
The system uses a single differential weighing device that measures weight changes during different filling phases. By segmenting the filling process into multiple phases and using one high-precision weighing device to monitor each phase separately, the system avoids the accumulation of errors that would occur with multiple weighing devices while maintaining high filling rates.
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 solution enables efficient and precise filling of a variety of products, including fine-grain and difficult-to-bag materials, with reduced air entrapment and accurate weight measurement, enhancing filling rates and precision while allowing for desired handling of bags during the filling process.
Implementation Method 1
The filling box is weighed separately by the associated weighing device so as to discharge from the filling box a predefined quantity of intended fill by way of differential weighing
Implementation Method 2
The control device is configured for timing the strength of the volume flow into the bag throughout the filling process so that the intended till is maintained at a high level during filling while overflow is concurrently prevented
Data Source
AI summary
A packaging machine and method for filling bags with a supporting structure to which at least one filling box is fastened which includes a conveyor element and to which a weighing device and a filling spout are assigned. A control device is provided. The filling box is retained non-communicating with the supporting structure and the assigned filling box and is weighed separately by the assigned weighing device to discharge from the filling box a predefined quantity of intended fill product by way of differential weighing and to fill it into the bag through the filling spout. The control device controls the strength of a volume flow into the bag over the time of the filling process so that the intended fill product is maintained at a high fill height while overflow is simultaneously prevented.