Pipette Pressure Curve Sensing for Unknown Liquid Properties
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Solution Overview
Problem
Laboratory automation devices face challenges in accurately determining the physical properties of unknown liquids, such as density and viscosity, which are crucial for precise handling and processing.
Innovation Solution
A method involving a pipetting arm to aspirate and dispense air and liquid in a controlled manner within a pipette, while measuring pressure curves to determine physical parameters like viscosity and surface tension using a pressure sensor, and employing equations to model the pipette and liquid properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a pipette is reused after contact with liquid, then operational efficiency is improved, but measurement precision deteriorates due to contamination and wetting effects
Solution Approach 1:
The patent employs disposable pipettes that are discarded after a single use. This eliminates contamination from previous liquid contacts and ensures consistent measurement precision for each determination, while the low cost of disposable pipettes maintains operational efficiency.
2Ease of operation
If multiple aspiration and dispensing cycles are performed, then liquid handling is more thorough, but measurement precision deteriorates due to repeated wetting of the interior surface
Solution Approach 1:
The patent segments the measurement process into distinct phases: first aspirating air to establish a baseline pressure curve, then aspirating liquid in a single pass to determine physical parameters. This segmentation prevents repeated wetting cycles that would alter surface properties and compromise measurement precision.
Solution Approach 2:
The patent performs preliminary aspiration of air before liquid contact to establish reference pressure values. This preliminary action prepares the system for accurate liquid measurement without requiring subsequent re-wetting cycles, thereby maintaining measurement precision.
3Measurement precision
If physical parameters are determined manually, then measurement precision can be verified, but productivity deteriorates due to time-consuming procedures
Solution Approach 1:
The system performs self-service by automatically determining physical parameters through computerized analysis of pressure curves. The control device automatically processes the pressure data, calculates physical parameters using stored equations, and stores results without requiring manual verification, thereby maintaining productivity while ensuring measurement precision through automated validation.
Solution Approach 2:
The patent replaces manual mechanical measurement procedures with automated electronic pressure sensing and computerized calculation. Pressure sensors automatically record curves during aspiration, and computer algorithms calculate physical parameters, eliminating time-consuming manual operations while maintaining or improving measurement precision.
4Measurement precision
If complex liquid handling procedures are used to determine multiple parameters, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent employs a universal pressure sensor and control device that can determine multiple physical parameters (density, viscosity, surface tension, wetting angle) through a single integrated system. The same hardware platform performs multiple measurement functions by analyzing different aspects of the pressure curve, thereby improving measurement precision without proportionally increasing device complexity.
Solution Approach 2:
The system determines multiple physical parameters by analyzing different characteristics of the pressure curve obtained during a single aspiration process. By extracting multiple parameters from one measurement dataset through mathematical analysis, the system improves comprehensive measurement precision without requiring multiple separate measurement devices or procedures.
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 accurate and automated determination of liquid properties, enhancing the precision and efficiency of laboratory automation systems by using disposable pipettes and minimizing interference from previous liquid contact.
Implementation Method 1
measuring a pressure curve in the pipette with a pressure sensor of the laboratory automation device
Implementation Method 2
an interior surface of the pipette is wetted with liquid solely one time
Data Source
Figure 1~2
AI summary
A method for determining physical parameters of a liquid (22) to be aspirated and/or dispensed by a laboratory automation device (10) comprises: pickup of a pipette (14) with the laboratory automation device (10); lowering the pipette (14) into a sample container (18) with the laboratory automation device (10), the sample container (18) containing the liquid (22); aspirating and dispensing air and liquid (22) with the laboratory automation device (10) in such a way, that a liquid level in the pipette (14) solely rises in a first step and solely lowers in a second step, such that an interior surface of the pipette (14) is wetted with liquid solely one time; and during aspirating and dispensing air and liquid (22), measuring a pressure curve (40) in the pipette (14) and determining the physical parameters from the pressure curve (40), the physical parameters comprising at least one of a surface tension, a wetting angle and a viscosity.