Peristaltic Pump Calibration Through Bubble-Sensor Aspiration Timing
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Solution Overview
Problem
Existing liquid extraction systems in automated analyzers face challenges due to varying tolerances in peristaltic hoses and pumps, leading to inaccurate process control and unscheduled maintenance, particularly due to the aging of components.
Innovation Solution
A method involving a known volume of liquid aspiration using a peristaltic pump, monitored by a bubble sensor, to calculate a calibration value based on the time difference between expected and actual aspiration times, allowing for parameter adjustments to compensate for pump and hose variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the parameterized limits are set more generously to account for tolerances in suction hoses, pumps, and environmental conditions, then error robustness of process control is improved, but measurement precision deteriorates
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the expected suction time parameter based on measured actual suction times. The system stores multiple expected suction time values and selects/apples corrections based on current operating conditions, allowing the control parameters to adapt to aging components and environmental variations while maintaining both robustness and precision
Solution Approach 2:
The patent implements feedback by measuring actual suction times and comparing them against expected values, then using the difference to correct subsequent measurements. The bubble sensor provides continuous feedback on liquid/air transitions, and the system uses this feedback to adjust calibration values and maintain accurate dispense volume control despite component tolerances and aging
2Manufacturing precision
If parameters are kept constant to reduce variability, then manufacturing precision is improved, but adaptability deteriorates
Solution Approach 1:
The patent applies dynamics by transitioning from static, constant parameters to dynamic parameters that automatically adjust based on measured performance. The expected suction time is not fixed but is corrected based on actual measurements, allowing the system to adapt to aging peristaltic tubes and pump variations while maintaining consistent process control through automated calibration
3Device complexity
If the suction speed of the pump is kept constant, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent replaces mechanical adjustment of pump speed with an optical/electronic measurement and correction system. Instead of mechanically varying pump speed to compensate for tolerances, the system uses a bubble sensor to optically detect liquid/air transitions and electronically calculates corrected suction times, substituting mechanical complexity with sensor-based measurement and computational correction
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
Enhances process control accuracy and extends the service life of peristaltic tubes by adapting parameters to changing conditions, reducing maintenance frequency and maintaining sensitivity.
Implementation Method 1
The sensor is configured to optically detect transitions from air to liquid in the extraction hose comprising the liquid
Data Source
AI summary
A method for calibrating a pump, comprising the steps of providing a known volume of a liquid in a container; aspirating the known volume with a pump through a channel; determining with a liquid sensor the time for aspiration of the whole known volume by measuring liquid/air changes in the channel; comparing the determined time for aspiration with an expected time for aspiration; calculating at least one calibration value depending on a deviation from the expected time for calibration; applying the at least one calibration value to parameters for the aspiration process and a related pump calibration device.