Volumetric Displacement Calibration for Liquid Handling Systems
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Solution Overview
Problem
Existing methods for calibrating liquid and solid substance volumes in laboratory devices are complex, costly, and lack the precision required by ISO 8655, often requiring liquid handling and temperature compensation, and are not user-friendly for frequent calibration.
Innovation Solution
A method and system using gas displacement volume measurement through pressure change in a closed volume, utilizing barometric pressure sensors for accurate calibration without liquid handling, allowing easy and frequent calibration with no need for precise scales.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gravimetric calibration method is used, then measurement precision is improved, but device complexity and ease of operation deteriorate
Solution Approach 1:
The patent replaces the mechanical gravimetric system (precision scale, manual weighing) with a pressure-based measurement system. Pressure sensors measure pressure changes in a closed volume when liquid is aspirated or dispensed, and volume is calculated using the compressibility of gas and liquid. This substitution eliminates the need for mechanical scales and complex manual weighing procedures while maintaining measurement precision.
Solution Approach 2:
The patent uses pneumatic principles by measuring pressure changes in a closed gas volume to determine liquid volume. When liquid is aspirated or dispensed, the gas volume changes, causing pressure changes that are measured by pressure sensors. This pneumatic approach simplifies the system compared to gravimetric methods while achieving the required measurement precision.
2Measurement precision
If gravimetric calibration method is used, then measurement precision is improved, but ease of operation worsens
Solution Approach 1:
The patent enables self-service calibration by allowing users to perform calibration without specialized training or equipment. The automated pressure-based system eliminates the need for users to master complex weighing techniques or understand temperature compensation procedures. Users simply connect the device and follow automated prompts, making calibration accessible to non-experts.
Solution Approach 2:
The replacement of manual gravimetric procedures with automated pressure sensing eliminates the need for careful manual handling and weighing operations. The system automatically measures pressure changes and calculates volumes, removing the skill-intensive steps of manual calibration while maintaining precision.
3Reliability
If regular calibration is performed, then reliability is improved, but loss of time increases
Solution Approach 1:
The patent facilitates periodic calibration by making the process so simple and quick that users can perform it regularly without significant time loss. The automated pressure-based system completes calibration in minutes rather than hours, enabling frequent reliability checks. Users can calibrate before each use or at regular intervals, maintaining high reliability without excessive time investment.
Solution Approach 2:
The self-service nature of the calibration system allows users to perform it quickly without external assistance. This reduces the time cost of regular calibration while maintaining reliability, as users can independently perform frequent checks without scheduling external service providers.
4Measurement precision
If external service providers are used for calibration, then measurement precision is maintained, but cost increases
Solution Approach 1:
The patent enables users to perform their own calibration, eliminating the need to subcontract to external service providers. This self-service capability maintains measurement precision through the accurate pressure-based system while eliminating the recurring costs of external calibration services, significantly reducing the cost of ownership.
Solution Approach 2:
The substitution of expensive external calibration services with an in-house automated system eliminates ongoing service costs. The one-time investment in the pressure-based calibration device replaces recurring payments to external providers, reducing the total cost of ownership while maintaining precision.
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
Achieves precision comparable to liquid weighting methods while being simpler, faster, and cheaper, reducing the cost of ownership and increasing quality control by enabling easy calibration of multiple systems simultaneously.
Implementation Method 1
The calibration device (1) comprises a pressure sensor (12) connected to said main chamber (10) and arranged to measure a pressure change inside said main chamber (10) resulting from the volume change of the aspired liquid
Data Source
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AI summary
The invention is achieved by a volumetric displacement calibration device (1) configured to be able to adapt at least one suction system (1000), comprising a tip (1006), having a volume VP, connected to a shaft (1003) comprising a volume change mechanism (1002). The device (1) comprises at least one main chamber (10) and one reference chamber (20), connected by a conduct (100) and a valve (102) to said main chamber (10) and at least one first pressure sensor (12) connected to said main chamber (10). The device (1) comprises also a second pressure sensor (22) connected to said reference chamber (20). The pressure sensors and calculation means allow to calculate an internal volume Vo, being the sum of the volume VP of said aspiration tip (1006), the volume (1005) of the shaft (1003) when the volume change mechanism (1002) is down. The invention is also achieved by a system (2) comprising the device (1) and at least one suction system (10001- 1000n) adapted to said device (1). The invention relates also to a calibration method of a volumetric fluid handling system (2) and comprising successive steps (a-m) to determine said volume Vo.