Dissolved Oxygen Sensor Luminophor End-of-Life Detection
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Solution Overview
Problem
Existing dissolved oxygen sensors are unsuitable for ultra-high purity environments due to material incompatibility, contamination, and disruption of fluid flow, and lack an effective indicator for component replacement, leading to unnecessary expenses and process disruptions.
Innovation Solution
A dissolved oxygen sensor with an optically transparent window and a luminophor that emits light in response to excitation, allowing for monitoring of light intensity to determine if the luminophor needs replacement, and an optical probe design that separates components to prevent electrical and optical crosstalk, enabling accurate measurement and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrochemical sensors with metal probes are used to measure dissolved oxygen, then oxygen concentration can be measured, but the metal probes contaminate the process fluid and are incompatible with ultra-high purity environments
Solution Approach 1:
The patent replaces the electrochemical measurement mechanism with an optical measurement system. An optical probe with a luminophor coating measures dissolved oxygen through fluorescence quenching, eliminating the need for metal probes that cause contamination. The optical system uses light excitation and detection instead of electrical currents, solving the contamination problem while maintaining measurement capability.
Solution Approach 2:
The patent uses a thin luminophor coating on an optical probe instead of a solid metal probe. The luminophor layer is a thin film that allows optical penetration while providing the measurement function. This thin film approach eliminates the bulk metal materials that cause contamination in ultra-high purity environments.
2Measurement precision
If metal probe tips are inserted into process fluid, then oxygen measurement is enabled, but fluid flow is disrupted causing bubbles and variations in dispense rates
Solution Approach 1:
The patent replaces the mechanical probe insertion method with an optical measurement approach. The optical probe measures oxygen through fluorescence quenching without requiring physical contact with the fluid that would disrupt flow patterns. This substitution eliminates flow disruption while maintaining measurement accuracy.
3Measurement precision
If luminophor is replaced on an accelerated schedule to ensure accurate measurement, then measurement accuracy is maintained, but unnecessary expenses are incurred and process disruptions occur
Solution Approach 1:
The patent incorporates a feedback mechanism that continuously monitors the luminophor's light emission intensity. When the luminophor degrades, the feedback system detects the change in emission characteristics and triggers an alarm or notification. This allows replacement only when actually needed, eliminating unnecessary replacements and associated process disruptions while maintaining measurement accuracy.
Solution Approach 2:
The luminophor system performs self-diagnosis through its optical properties. The luminophor's own light emission serves as the indicator of its health status, eliminating the need for external monitoring systems or scheduled maintenance. The system tells itself when it needs replacement through changes in its optical characteristics.
4Volume of moving object
If optical probe components are placed close together for compact design, then device size is reduced, but electrical and optical crosstalk occurs affecting measurement accuracy
Solution Approach 1:
The patent extracts the optical measurement components from the electrical probe structure, creating a separate optical probe system. This separation eliminates the crosstalk problem inherent in combined electrochemical-optical probes. The optical components (light source, luminophor, detector) are isolated from electrical components, allowing compact design without compromising measurement accuracy.
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 sensor provides a reliable indication for luminophor replacement, maintaining accurate functioning while reducing unnecessary replacement and avoiding process disruptions in ultra-high purity environments.
Implementation Method 1
a luminophor that emits light in response to excitation
Implementation Method 2
a photodiode receives the light emitted by the luminophor
Data Source
AI summary
Embodiments as disclosed herein may include a sensor including a luminophor exposed to a fluid flow path. The luminophor may emit light in response to illumination by an excitation light source. The magnitude of light emitted by the luminophor in response to illumination may be determined. It can be determined if this magnitude is within a threshold of the baseline magnitude and an alarm state set based on this determination. This alarm state may indicate that the luminophor has reached an end-of-life state or otherwise should be replaced.