Capsule Weighing in Filling Machines via Speed Deceleration
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Solution Overview
Problem
Current methods for weighing capsules in automatic packaging machines face challenges in achieving high precision and accuracy due to disturbances from vibrations, accelerations, and air flows, especially during total weight control, which compromises machine productivity and leads to unacceptable rejection rates, particularly with powdery and granular pharmaceutical products.
Innovation Solution
A method that involves selectively slowing down the machine during weighing intervals to increase measurement time and inhibit operating station operations, allowing for higher precision and accuracy in statistical weight control of a sample, while maintaining total weight control for all capsules, by decelerating and accelerating the machine speed to minimize disturbances and perturbations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the machine operates at nominal speed for total weight control of all capsules, then machine productivity is maintained, but measurement precision and accuracy deteriorate due to insufficient weighing time and disturbances
Solution Approach 1:
The patent divides weight control into two separate modes: statistical weight control for sample capsules and total weight control for all capsules. This segmentation allows the system to apply different measurement strategies to different subsets of capsules, optimizing both productivity and precision without requiring the entire production line to slow down.
Solution Approach 2:
The patent applies partial action by performing precise measurements on only a statistical sample of capsules rather than all capsules. This partial measurement approach achieves sufficient quality control while maintaining high-speed operation for the majority of production, resolving the contradiction between full inspection precision and overall productivity.
2Measurement precision
If the machine slows down to allow scale stabilization and reduce disturbances, then measurement precision improves, but machine productivity decreases
Solution Approach 1:
The patent segments the production stream into a statistical sample group and the remaining capsules. Only the sample group undergoes the time-consuming precise measurement process, while the rest continue at nominal speed. This segmentation confines the productivity impact to a minimal subset while achieving high precision where needed.
Solution Approach 2:
The patent implements periodic statistical control where measurements are taken at regular intervals on selected capsules rather than continuously on all capsules. This periodic sampling approach allows the system to maintain high-speed operation while periodically verifying quality with high-precision measurements.
3Measurement precision
If the machine operates at reduced speed during weighing intervals, then measurement accuracy improves by reducing vibrations and air flows, but dosing consistency deteriorates due to speed-dependent dosing variations
Solution Approach 1:
The patent separates the dosing process from the measurement process by performing dosing on all capsules at nominal speed, then selectively measuring only a statistical sample. This segmentation ensures that dosing consistency is maintained for all capsules while measurement accuracy is optimized for the sample, avoiding the contradiction entirely.
Solution Approach 2:
The patent performs dosing as a preliminary action at nominal speed for all capsules before the statistical sampling and measurement phase. This ensures that dosing consistency is established under optimal conditions, and subsequent measurements are performed on already-dosed capsules without affecting dosing quality.
Data Source
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AI summary
A method for weighting containers (100), particularly soft capsules or hard capsules, in a filling machine (1) suitable to fill the containers (100) with a product, and comprising a feeding station (F) of the containers (100), a plurality of operating stations (A, D, R) for carrying out operations on the containers (100), weighting means (G, T) for weighting the containers (100), and moving means (7) provided with a plurality of supports (8) with corresponding seats (9) for housing the containers (100) and arranged to move the latter ones sequentially through the operating stations (A, D, R), comprises supplying the sup-ports (8) with the containers (100) in the feeding station (F), carrying out operations on the containers (100) by the operating stations (A, D, R), and weighting the containers (100) by the weighting means (G, T) with a predetermined precision and accuracy.