Clog Detection in Clinical Sampling Pipette
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for determining the quality and integrity of liquid aspiration processes, particularly for small aspiration volumes, are inadequate as they rely on pressure differential measurements which become erratic with decreasing sample volumes and are ineffective in detecting full or partial clogs.
Innovation Solution
The method involves recording and analyzing aspiration pressure data during a predetermined period before the end of the vacuum pumping phase, calculating an average pressure reading, and comparing it to a minimum threshold to determine if the aspiration process is free from clogs, and applying a similar analysis during dispensing to ensure the absence of clogs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure differential measurements are used to detect clogs in liquid aspiration, then clog detection is enabled, but measurement precision deteriorates with decreasing sample volumes
Solution Approach 1:
The patent changes the measurement parameter from pressure differential to absolute pressure within the pipette. By monitoring absolute pressure during the aspiration phase and comparing it to a predetermined threshold, the system achieves reliable clog detection without the precision problems of pressure differential measurements at small volumes. This parameter transformation resolves the contradiction by enabling accurate detection across all volume ranges.
2Reliability
If multiple aspiration tests are performed to verify liquid quality, then detection reliability improves, but device complexity increases
Solution Approach 1:
The patent merges multiple aspiration quality verification functions into a single integrated test. Instead of performing separate pressure difference tests, pressure recovery tests, and pressure shape tests as disclosed in prior art, the system combines these into one aspiration phase pressure monitoring that detects clogs, air aspiration, and other abnormalities simultaneously. This consolidation maintains high reliability while reducing device complexity.
Solution Approach 2:
The single aspiration phase pressure measurement serves multiple detection functions: it detects clogs by comparing pressure to a threshold, identifies air aspiration through pressure profile analysis, and verifies liquid presence. This multi-functionality approach allows one measurement system to replace multiple specialized tests, resolving the contradiction between reliability and complexity.
3Productivity
If pressure differential tests are used for small aspiration volumes, then aspiration monitoring is enabled, but measurement accuracy deteriorates
Solution Approach 1:
The patent transforms the measurement approach from pressure differential to absolute pressure measurement within the pipette chamber. This parameter change enables accurate monitoring at small aspiration volumes because absolute pressure measurements are not subject to the same noise and error issues as differential measurements at low volumes. The system maintains productivity through continuous monitoring while achieving the required 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
This approach effectively detects full or partial clogs in both aspiration and dispensing processes, ensuring the quality and integrity of the liquid transfer, even for small volumes with varying viscosities, by using average pressure readings within the system's geometrical and pumping characteristics.
Implementation Method 1
Some type of vacuum pressure activated device, such as a piston assembly, may be incorporated into the pipette to aspirate liquid into the pipette
Implementation Method 2
A pressure transducer measures the negative pressure developed within the pipette during the aspiration process
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Analyzing the pressure profile generated during a predetermined period of time prior to the end of an aspiration or dispensing process and comparing a pressure reading to predetermined values to determine if the aspiration or dispensing pipette was free of clogs.