Aspirate-Dispense Volume Control Using Secondary Fluid Feedback
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Solution Overview
Problem
Existing aspiration-dispense systems rely on time to monitor and control fluid volume, leading to inaccuracies due to variations in flow rate caused by pressure, conduit physical characteristics, and fluid viscosity, resulting in wasted fluid.
Innovation Solution
A controller that uses a secondary fluid to monitor flow parameters, determining the volume of primary fluid aspiration or dispensing based on calibration data, and controls the flow of fluids to achieve precise volume control by regulating pressure and valve operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time-based monitoring is used to control fluid volume, then the system is simple to operate, but measurement precision deteriorates due to flow rate variations
Solution Approach 1:
A secondary fluid is introduced as an intermediary between the pressure control system and the primary fluid. The secondary fluid transmits pressure changes from the pressure control device to the primary fluid without requiring direct contact, enabling indirect measurement of primary fluid volume through flow parameter changes in the secondary fluid. This resolves the contradiction by providing accurate measurement through the intermediary's response to pressure changes.
2Loss of substance
If flow rate variations are not compensated, then the system is simpler, but loss of substance increases due to inaccurate volume control
Solution Approach 1:
The system continuously monitors flow parameters of the secondary fluid and uses this feedback to determine the actual volume of primary fluid aspirated or dispensed. The controller adjusts pressure based on the measured volume to achieve the target volume, creating a closed-loop feedback system that compensates for flow rate variations and prevents fluid waste.
3Measurement precision
If manual calibration is performed, then measurement precision can be improved, but loss of time increases due to calibration requirements
Solution Approach 1:
The system performs automatic calibration by measuring the flow parameters of the secondary fluid during normal operation and using these measurements to determine primary fluid volume. The calibration data is stored and reused for subsequent operations, eliminating the need for repeated manual calibration and reducing time loss while maintaining measurement 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 accurate fluid volume control with reduced waste by using secondary fluid flow parameters, independent of primary fluid characteristics, and facilitates automation with reduced human error and calibration time.
Implementation Method 1
a flow meter to measure a flow rate of the secondary fluid
Implementation Method 2
a pressure regulator to control a pressure of the secondary fluid
Implementation Method 3
a valve to limit a flow of the primary or secondary fluid
Data Source
Figure 1
Figure 2~3b
Figure 4~5b
AI summary
A controller configured to control one or more of aspiration and dispensing of a primary fluid by an aspirate-dispense apparatus, the aspirate-dispense apparatus comprising a secondary fluid in working communication with the primary fluid, wherein the controller is configured to: receive measurement signalling for a monitored flow parameter of the secondary fluid; determine, using calibration data, a volume of aspirated or dispensed primary fluid based on the received measurement signalling, the calibration data defining a relationship between the volume of aspirated or dispensed primary fluid and the monitored flow parameter of the secondary fluid; and control the flow of primary or secondary fluid based on the determined volume to aspirate or dispense a specific volume of primary fluid.