Pipette Pressure Discharge for Reproducible Liquid Dosing
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Solution Overview
Problem
Existing pipetting methods struggle with achieving accurate and reproducible liquid doses, particularly in high-throughput applications, due to variations in minimum aspirable volumes and volumes dispensed, which are influenced by previous pipetting steps.
Innovation Solution
A method involving controlled loading of pipettes with working media at specific pressures and discharging the pressure through a valve arrangement to reference pressure between loadings, ensuring precise and reproducible liquid dose production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a pipette is used to aspirate and dispense liquid without pressure discharge between operations, then the device complexity is reduced, but the manufacturing precision of liquid doses deteriorates due to variations in minimum aspirable volumes and volumes dispensed
Solution Approach 1:
The patent extracts the pressure discharge function into a separate, dedicated valve arrangement that operates independently from the main pipetting mechanism. This discrete pressure discharge valve is integrated into the existing pipette system, allowing pressure normalization without adding complex multi-functional components. The valve arrangement specifically targets and resolves pressure variations between operations, thereby improving liquid dose accuracy while maintaining relatively simple device architecture.
Solution Approach 2:
The patent changes the pressure parameter of the working medium by introducing a controlled discharge mechanism that actively normalizes pressure to reference levels between aspirating and dispensing operations. This dynamic pressure parameter adjustment ensures consistent liquid volume delivery by eliminating pressure-induced volume variations, directly addressing the manufacturing precision issue without requiring complex mechanical redesign.
2Reliability
If pressure is not discharged between loadings, then the loss of time is reduced, but the reliability of liquid dose volume deteriorates due to influence from preceding pipetting steps
Solution Approach 1:
The patent implements a preliminary pressure discharge action between pipetting operations that proactively normalizes pressure conditions before the next liquid dose operation. This preliminary pressure normalization prevents carryover effects from preceding steps, ensuring each liquid dose is delivered under consistent reference pressure conditions, thereby improving reproducibility. The discharge timing is optimized to occur during natural transition periods, minimizing impact on overall processing time.
3Quantity of substance
If the minimum aspirable volume is reduced without pressure discharge control, then the quantity of substance handled is improved, but the manufacturing precision deteriorates due to uncontrolled pressure variations
Solution Approach 1:
The patent implements a feedback mechanism through the pressure discharge valve arrangement that monitors and corrects pressure deviations from reference conditions between aspirating and dispensing operations. This feedback control ensures that even when handling small liquid volumes, the pressure remains normalized, preventing the amplification of pressure-related volume errors. The system automatically adjusts pressure conditions based on operational state, maintaining high precision across the full range of aspirable volumes.
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 allows for highly reproducible and accurate liquid doses, reducing the need for discarding initial portions and minimizing wasted liquid, especially in multi-dispensing scenarios.
Implementation Method 1
A flow restriction, preferably a capillary, which is arranged in the flow connection between the opening of the pipette connector and the pressure source
Implementation Method 2
at least one positive and/or negative pressure source with respect to reference pressure
Implementation Method 3
discharging a pressure in said first working medium through a controlled valve arrangement to the reference pressure between said first and said second loadings
Data Source
AI summary
A method is disclosed for controlling at least one of aspirating and of dispensing a liquid dose or of producing a liquid dose in a pipette or in receptacle, the method having the steps of first loading a first pipette with a first working medium at a first pressure having a first sign with respect to a reference pressure, thereby dispensing the liquid dose into the receptacle or aspirating the liquid dose into the first pipette, second loading a second pipette with a second working medium at a second pressure having a second sign with respect to the reference pressure, thereby dispensing the liquid dose into the receptacle or aspirating the liquid dose into the second pipette, discharging a pressure in the first working medium through a controlled valve arrangement to the reference pressure between first and second loadings. A pipetting device is also disclosed.