Weighing Method for Pharmaceutical Containers Using Reference Samples
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Solution Overview
Problem
Existing weighing methods in the pharmaceutical, medical, and food sectors face challenges in achieving precise and repeatable weight measurements due to environmental factors such as air flow, which can introduce measurement errors, especially in sterile and controlled environments where laminar air flow can generate micro-vortices and turbulences, making it difficult to accurately compensate for these errors.
Innovation Solution
A weighing method that utilizes a weighing unit with multiple devices, where containers filled with substances and reference sample containers with known weights and sizes are weighed to calculate and correct for measurement errors, allowing for precise estimation and correction of weight measurements by assuming the measurement error of filled containers is equal to that of the reference samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a laminar air flow is generated from top down to protect the sterile environment, then contamination is reduced, but measurement precision deteriorates due to micro-vortices and local turbulences
Solution Approach 1:
The weighing system is divided into multiple independent weighing devices (first weighing device and second weighing device), allowing separate measurement of reference sample and filled container. This segmentation enables independent error characterization for each measurement position, improving overall measurement precision despite environmental disturbances.
Solution Approach 2:
A reference sample container with known weight is placed on one weighing device to create a reference measurement that copies the environmental conditions affecting the filled container measurement. By comparing the reference measurement with its known value, the system characterizes environmental errors (such as those from laminar air flow) and uses this information to correct the filled container measurement, thereby maintaining measurement precision in a contaminated-protected environment.
2Measurement precision
If software compensation is used to correct weighing errors, then measurement accuracy improves, but reliability deteriorates when environmental conditions vary beyond compensation ranges
Solution Approach 1:
The system performs preliminary measurement of a reference sample container with known weight under the same environmental conditions as the filled container. This preliminary action characterizes the environmental errors (laminar air flow effects, turbulence) before measuring the filled container, allowing the system to establish correction factors in advance that are valid for the current environmental state, thereby maintaining both accuracy and reliability.
Solution Approach 2:
The system uses the reference sample measurement as feedback to determine environmental error characteristics. By comparing the measured reference weight with its known value, the system calculates error factors and applies them to correct the filled container measurement. This feedback mechanism dynamically adapts to environmental variations, maintaining measurement reliability even when conditions change beyond fixed compensation ranges.
3Measurement precision
If multiple weighing devices are used to enable reference sample weighing, then measurement precision improves through error correction, but device complexity increases
Solution Approach 1:
The second weighing device serves multiple functions: it measures the reference sample container to characterize environmental errors, and can also measure filled containers when needed. This multi-functionality allows the system to achieve improved measurement precision through reference measurements without requiring dedicated separate equipment for each function, thereby limiting the increase in device complexity.
Solution Approach 2:
The weighing system uses itself to characterize and correct its own errors. The reference sample measurement on one weighing device provides information about environmental conditions affecting all weighing devices, allowing the system to self-diagnose and self-correct measurement errors. This self-service approach eliminates the need for external calibration equipment or complex additional systems, achieving error correction with minimal added 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 reduces measurement errors to microgram levels, providing reliable and accurate weight measurements by accounting for environmental influences, thereby ensuring safety and precision in pharmaceutical and food product dosing.
Implementation Method 1
a) making available a weighing device (30) provided with a container support (22) and configured to detect a weight force acting on the container support (22) in order to determine a weight of a container (12) filled with a desired quantity of substance
Implementation Method 2
there is a known practice of generating, inside the at least partly closed weighing chamber created in this way, a laminar air flow forced from the top down
Data Source
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AI summary
A weighing method for weighing containers of pharmaceutical, medical, food substances or similar, in which the containers are subject to the action of an air flow, comprises making available a weighing unit (20) provided with two or more weighing devices (30) and weighing containers (12) filled with a desired quantity of substance, occupying respective weighing devices (30) of said weighing unit (20), supplying a weight value of said containers (12) obtained from an actual weight value which is corrected by adopting a measurement error that estimates the effect of the action of the air flow.