Channel Pump Backflow Compensation via Pressure Difference
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Solution Overview
Problem
Automated pipetting systems face challenges in achieving precise fluid handling due to fluid backflow caused by pressure differences in pump conduits, which affects the accuracy and efficiency of pipetting operations, especially when switching between pipetting and washing modes.
Innovation Solution
A pipetting system with a channel pump that includes tip-sided and reservoir-sided ports connected by pump conduits, where a controller determines pressure differences to adjust the pipetting period and compensate for fluid backflow, ensuring accurate and extended pipetting periods to achieve precise fluid delivery, and a method for calibrating the system to establish relationships between pressure differences and fluid backflow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a rotary displacement pump is used for both pipetting and washing operations, then the pump can handle both functions with a single device, but fluid backflow occurs due to pressure differences in the pump conduits reducing pipetting precision
Solution Approach 1:
The controller continuously monitors the actual fluid volume delivered by the rotary displacement pump and compares it to the expected volume. Based on this feedback, the controller automatically adjusts pump operation parameters to compensate for backflow effects, thereby maintaining pipetting precision while using a single pump for both pipetting and washing operations
Solution Approach 2:
The system changes operational parameters such as pump speed, pressure, and flow rate depending on whether the current operation is pipetting or washing. By dynamically adjusting these parameters, the system optimizes performance for each specific task while compensating for backflow effects during pipetting operations
2Manufacturing precision
If plunger pumps are used for pipetting operations, then precise pipetting can be achieved, but separate pumps are required for pipetting and washing operations increasing system complexity
Solution Approach 1:
The patent makes a single rotary displacement pump capable of performing both pipetting and washing functions by implementing intelligent control that adjusts pump operation based on the current task. This multi-functionality eliminates the need for separate pumps while maintaining precision through real-time compensation for backflow effects
Solution Approach 2:
The controller uses feedback from flow sensors and pressure monitors to detect backflow conditions and automatically adjusts pump parameters. This feedback mechanism enables a single pump to achieve precision comparable to dedicated plunger pumps while handling multiple operations
3Manufacturing precision
If the pipetting period is extended to compensate for fluid backflow, then accurate fluid delivery can be achieved, but the pipetting operation time increases
Solution Approach 1:
Instead of using a fixed extended pipetting period, the system dynamically adjusts the operation duration based on real-time monitoring of actual fluid delivery. The controller continuously adapts the pipetting period to compensate for backflow effects, achieving accurate fluid delivery without unnecessary time extension
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
The system enables highly precise and flexible pipetting by compensating for fluid backflow, allowing for accurate delivery of both small and larger fluid volumes, and facilitates efficient calibration to maintain pipetting accuracy across different operational conditions.
Implementation Method 1
a channel pump (3) having at least one tip-sided port (6) connected to a pipetting tip (4) by a tip-sided pump conduit (5) for generating a positive or negative pressure in the pipetting tip (4)
Implementation Method 2
The channel pump (3) exhibits a fluid backflow caused by a pressure difference between fluid pressures in the tip- and reservoir-sided pump conduits (5, 8)
Data Source
AI summary
A system and a method for the automated pipetting of fluids are disclosed as well as a method for calibrating the system. A channel pump having at least one tip-sided port connected to a pipetting tip by a tip-sided pump conduit for generating a positive or negative pressure in the pipetting tip, and at least one reservoir-sided port connected to a system fluid reservoir by a reservoir-sided pump conduit is provided. The channel pump when operated at a nominal flow rate exhibits a fluid backflow caused by a pressure difference in the tip- and reservoir-sided pump conduits which results in an effective flow rate compared to the nominal flow rate. Such a pressure difference can be used to determine an extended pipetting period which extends a pipetting period of the channel pump operating at the nominal flow rate, and to calibrate the system.