Liquid Metering in Analytical Devices
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Solution Overview
Problem
In wet chemistry analytical devices, air bubbles and liquid films formed during liquid metering can lead to incorrect volume settings and impaired measurement accuracy due to the activation of the dose measuring device by air bubbles, especially during purging and metering processes.
Innovation Solution
A method where an additional volume of liquid is drawn into the metering tube beyond the dose measuring device, and the status of the device is checked to ensure the absence of air bubbles or liquid films, allowing for precise liquid volume setting and continuous measurement by repeating the process until the device remains inactive, indicating air bubble-free conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid is drawn at high speed into the metering unit during purging and metering, then the metering process is efficient and productive, but air bubbles are drawn in together with the liquid causing erroneous activation of the dose measuring device
Solution Approach 1:
The patent applies preliminary action by performing a purging step before the actual metering operation. During purging, the system intentionally draws liquid at high speed to clear air bubbles from the tubing and metering unit, preparing the system for accurate measurement. This preliminary clearing action prevents air bubbles from interfering with subsequent dose measurements, thus maintaining both high productivity and reliability.
Solution Approach 2:
The patent extracts the harmful air bubbles from the liquid stream by using a separate purging cycle. The dosing pump operates in a clearing mode that specifically targets and removes air bubbles from the metering unit and tubing before the actual dosing begins. This extraction of the harmful element (air bubbles) allows the main dosing operation to proceed with high reliability while maintaining efficient throughput.
2Productivity
If the dose measuring device is activated by air bubbles or liquid films, then the metering process continues without interruption, but the volume to be metered is not set correctly impairing measurement accuracy
Solution Approach 1:
The patent employs feedback by using the dose measuring device to detect the presence of air bubbles or liquid films during the metering process. When the dose measuring device is erroneously activated by an air bubble, the system receives feedback about this condition and can respond by correcting the volume setting or initiating another purging cycle. This feedback mechanism ensures that measurement accuracy is maintained while allowing continuous operation.
Solution Approach 2:
The patent applies periodic action by implementing repeated purging cycles at intervals during the metering process. Instead of attempting to detect and correct each air bubble individually, the system periodically interrupts the dosing operation to perform a quick purging cycle that removes accumulated air bubbles. This periodic maintenance approach keeps the measurement precision high while minimizing interruptions to overall productivity.
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 ensures accurate liquid volume setting and prevents incorrect dosing and incomplete rinsing, enhancing the measurement accuracy and reliability of the analytical device by reliably detecting and addressing air bubbles and liquid films.
Implementation Method 1
the status of the dose measuring device is checked, and a conclusion is drawn from this status check regarding the presence of an air bubble-free liquid in the metering tube
Data Source
AI summary
The present disclosure relates to a method for metering a liquid into a wet chemistry analytical device wherein a specified volume of individual liquids is placed in a metering unit consisting of a metering container and at least one dose measuring device. During the filling of the metering container with the respective liquid, after the activation of the dose measuring device, an additional volume of the liquid is drawn into the metering tube beyond the position of the dose measuring device, wherein during this procedure and afterwards the status of the dose measuring device is checked, and a conclusion is drawn from this regarding the presence of an air bubble-free liquid in the metering tube.