Dispensing Probe Wear Detection for Accurate Liquid Handling
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Solution Overview
Problem
Existing dispensing devices fail to ensure accurate dispensing when using probes that have worn tips due to repeated penetration of sealed specimen containers, leading to reduced accuracy.
Innovation Solution
A dispensing device with a probe, sensor, and drive unit that measures the change in probe length by detecting contact with a reference surface to determine the appropriate replacement time, ensuring accurate dispensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the probe is repeatedly used to penetrate the plug of sealed specimen containers, then the penetration function is maintained, but the probe length shortens and dispensing accuracy deteriorates
Solution Approach 1:
The system performs preliminary measurement of the probe length before dispensing operations. By measuring the probe length in advance using a sensor that detects the position where the probe tip contacts a reference surface, the system can calculate the lowering amount needed to maintain accurate dispensing position, preventing accuracy deterioration before it occurs
Solution Approach 2:
The system implements feedback control by continuously monitoring probe length changes and adjusting the probe lowering amount accordingly. The control unit calculates the difference between the measured probe length and a reference length, then adjusts the lowering amount to compensate for wear, ensuring consistent dispensing accuracy throughout the probe's service life
2Manufacturing precision
If the probe is replaced frequently to maintain dispensing accuracy, then dispensing accuracy is maintained, but operational time and productivity decrease
Solution Approach 1:
The system dynamically adjusts the probe lowering amount parameter based on measured probe length changes. Instead of replacing the probe based on fixed usage time or count, the system modifies the operational parameter (lowering amount) to compensate for wear, allowing the probe to maintain accuracy for extended periods and reducing replacement frequency
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 solution allows for timely replacement of probes, maintaining dispensing accuracy by correcting the probe's lowering amount based on wear, thereby preventing reduced accuracy.
Implementation Method 1
a sensor configured to detect contact of a tip of the probe
Data Source
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AI summary
An object of the invention is to provide a dispensing device and a probe state checking method capable of grasping an appropriate replacement time of a probe while reducing a decrease in dispensing accuracy. Therefore, according to the invention, in a dispensing device including: a probe configured to aspirate and eject a liquid; a sensor configured to detect contact of a tip of the probe; a drive unit configured to drive the probe in an up-down direction; and a control unit configured to control the drive unit, the control unit performs a checking operation of checking a change in a length of the probe by lowering the probe by the drive unit until contact with a predetermined reference surface forming a part of the dispensing device is detected.