Fluorometer Partial Recalibration for Zero Point Drift

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Solution Overview

Problem

Existing fluorometric monitoring systems face challenges in accurately detecting low concentrations of fluorescent tracers in membrane separation processes, leading to potential errors in membrane integrity assessment.

Innovation Solution

The system performs a partial recalibration of the fluorometer by adjusting the intercept of the calibration curve based on controlled changes in the concentration of a fluorescent tracer introduced into the feed stream, allowing for improved accuracy without full recalibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fluorometer is used to detect very small concentrations of fluorescent tracer in membrane separation processes, then the ability to monitor membrane integrity is improved, but measurement precision deteriorates due to calibration errors and zero point drift

Engineering Contradiction:
Improvemembrane integrity monitoringVSAvoidtracer concentration measurement
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by adjusting the intercept parameter of the calibration curve to compensate for zero point drift. The system dynamically modifies the calibration parameters based on measured zero point shifts, thereby maintaining measurement precision despite changes in operating conditions over time.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If a full multi-point calibration is performed to improve measurement precision, then calibration accuracy is improved, but loss of time increases due to system shutdown requirements

Engineering Contradiction:
Improvecalibration accuracyVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements partial calibration by performing only a zero-point calibration rather than a full multi-point calibration. This partial action is sufficient to correct the specific issue of zero point drift while avoiding the time-consuming full calibration process, thus resolving the contradiction between calibration accuracy and calibration time.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system performs a preliminary zero-point calibration check at regular intervals during operation. This preliminary action detects zero point drift early and triggers only the necessary partial recalibration, preventing the need for more extensive full calibrations and minimizing system shutdown time.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If the fluorometer is recalibrated frequently to maintain measurement precision, then measurement precision is improved, but productivity decreases due to continuous shutdowns

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidmembrane separation process output
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent uses partial zero-point calibration instead of full calibration, which requires minimal system shutdown time. This partial recalibration can be performed frequently without significantly impacting productivity, while still maintaining measurement precision by correcting zero point drift.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system incorporates feedback by continuously monitoring the zero point and triggering recalibration only when drift is detected. This feedback mechanism ensures calibration is performed only when necessary, maintaining measurement precision while minimizing interruptions to productivity.

Inventive Principle:
Principle #23Feedback

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 enhances the accuracy of fluorometric measurements, particularly at ultralow concentrations, by correcting for zero point drift, thereby maintaining the reliability of membrane separation process monitoring.

Implementation Method 1

a fluorometer used to monitor the process may undergo a full, multi-point calibration. The full calibration process may involve fluorometrically analyzing a reference solution

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP3759466B1Calibration of a fluorometer for an ultra-low concentration measurement range
Publication Date: 2025.01.22 ECOLAB USA INC
  • EP3759466B1 patent drawingFigure 1
  • EP3759466B1 patent drawingFigure 2
  • EP3759466B1 patent drawingFigure 3

AI summary

A fluorometer may be used to measure ultralow concentrations of fluorescing species, such as ultralow concentrations of fluorescent tracer passing through a reverse osmosis membrane into a permeate stream. In some examples, the fluorometer may be recalibrated by resetting some but not all of the calibration parameters used to determine the concentration of fluorescent tracer in the permeate based on the measured fluorescent response of the fluorometer. For example, an intercept of a calibration curve may be reset or recalibrated for the fluorometer in situ, potentially providing significant accuracy improvements even though the fluorometer has not undergone a full recalibration.