Pipette Tip Vibration Control for Liquid Dosing
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Solution Overview
Problem
Existing pipetting methods cannot continuously monitor and control the precise aspiration and dispensing of liquid quantities during the pipetting process, especially for small volumes, due to limitations in accurately determining the amount of dosing liquid in the pipette tip while it is immersed in the liquid.
Innovation Solution
A method that iteratively adjusts the pipetting process by determining a reference variable representing the target liquid quantity, which deviates from the actual quantity present, and uses vibration analysis to match the detected variables with the reference variables, allowing for precise control of aspiration and dispensing through iterative excitation and detection of vibration shapes, independent of vibration coupling quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If vibration analysis is used to determine liquid quantity in a pipette tip during aspiration/dispensing, then measurement precision is improved, but the method becomes complex to implement continuously during the pipetting process
Solution Approach 1:
The patent implements continuous feedback control by iteratively comparing the detected vibration shape variables with reference variables and adjusting the aspiration/dispensing process accordingly. The control method repeatedly determines reference variables representing target quantities, detects actual quantities through vibration analysis, compares them, and adjusts the process until they match, enabling precise real-time control of liquid quantities during pipetting operations
Solution Approach 2:
The patent applies preliminary action by pre-determining reference variables that represent target liquid quantities before the actual pipetting process. These reference variables are established in advance through calibration or calculation, allowing the system to compare actual measurements against predetermined standards during continuous monitoring and control of the aspiration and dispensing processes
2Productivity
If the pipette tip remains immersed in dosing liquid during measurement, then continuous monitoring is enabled, but vibration coupling quality varies affecting measurement accuracy
Solution Approach 1:
The patent applies dynamics by making the measurement system adaptable to varying vibration coupling conditions. Instead of requiring fixed coupling quality, the method dynamically adjusts by iteratively comparing detected vibration variables with reference variables and continuing the process until convergence is achieved, allowing accurate measurements regardless of coupling variations that occur when the pipette tip remains immersed in liquid
Solution Approach 2:
The patent utilizes parameter changes by monitoring how vibration shape variables change during the aspiration and dispensing processes. The method detects these parameter changes iteratively and compares them against reference variables representing target quantities, enabling the system to track liquid quantity changes in real-time while the pipette tip remains immersed in the dosing liquid
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
Enables continuous, precise control of liquid quantities during aspiration and dispensing, ensuring high accuracy and consistency regardless of the quality of vibration coupling, allowing for precise metering even with interchangeable pipette tips.
Implementation Method 1
exciting the pipette tip (32) to vibrate and detecting a vibration shape of the excited pipette tip (32)
Implementation Method 2
coupling ultrasound into the wall of a suction tube of a pipetting device and measuring the attenuation of the ultrasound signal
Implementation Method 3
The publication of the prior art proposes piezocrystals for coupling ultrasound into the intake manifold and for measuring the damping of the ultrasound signal
Data Source
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AI summary
The invention relates to a method for determining a quantity of a dosing liquid aspirated through a dosing opening of a pipette tip into a holding volume of the pipette tip and/or dispensed from the holding volume of the pipette tip, wherein the method comprises the following steps: providing at least one reference variable (61, 63, 65) of at least one reference form of vibration; exciting a mode of vibration of at least one vibration section of the pipette tip; detecting at least one variable of the excited mode of vibration of the vibration section; and comparing the at least one detected variable of the excited mode of vibration to the at least one reference variable (61, 63, 65) of the reference mode of vibration. The method is a control method in which providing the at least one reference variable (61, 63, 65) comprises the following step: determining the at least one reference variable (61, 63, 65) such that it represents a desired target dosing liquid quantity which, at the time of determination, deviates from an actual dosing liquid quantity present in the holding volume, wherein the steps of exciting the mode of vibration, detecting the at least one excited variable and comparing the same to the at least one reference variable (61, 63, 65) are iteratively repeated during an aspiration of dosing liquid with the pipetting opening immersed in dosing liquid, or during a dispensation of dosing liquid, until the at least one detected variable is concordant with the at least one reference variable (61, 63, 65).