Excimer Lamp TOC Analyzer with Temperature Compensation
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Solution Overview
Problem
Current TOC measurement devices for pure or ultrapure water face challenges in sensitivity, accuracy, useful lifetime, and measuring speed, and pose environmental and safety concerns due to the use of mercury lamps, which degrade quickly and require hazardous handling.
Innovation Solution
A device using an excimer lamp as the radiation source for TOC measurement, which emits radiation nearly instantly upon switching on, has a longer operational lifetime, and is safer and more environmentally friendly, combined with temperature sensors for precise conductivity compensation and dynamic control to stop the oxidation reaction when stabilized, allowing for detection of low TOC concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mercury gas lamp is used as the radiation source for UV-oxidation, then the oxidation reaction can be induced effectively, but the lamp degrades quickly and requires frequent replacement and hazardous handling
Solution Approach 1:
The patent changes the radiation source from a mercury gas lamp to an excimer lamp, which operates at different wavelengths (172 nm for Xe2, 146 nm for Kr2). This parameter change in the light source eliminates mercury toxicity while maintaining effective UV-oxidation capability, resolving both the reliability and harmful factors contradictions
Solution Approach 2:
The excimer lamp represents a replacement that, while having its own lifetime limitations, eliminates the hazardous mercury content. The new lamp can be disposed of as general electrical waste rather than requiring special hazardous material handling procedures
2Productivity
If a mercury gas lamp is used for TOC measurement, then oxidation can be achieved, but the lamp requires a pre-heating time of 30 seconds which delays work progress
Solution Approach 1:
The excimer lamp is designed to emit radiation nearly instantly upon switching on, eliminating the 30-second pre-heating period required by mercury lamps. This preliminary readiness state allows measurements to begin immediately, significantly improving productivity and reducing time loss
Solution Approach 2:
The patent implements dynamic control where the excimer lamp is switched on only when needed for measurement and turned off when not in use. This periodic operation, enabled by the lamp's instant-on capability, eliminates unnecessary radiation time while maintaining measurement readiness
3Measurement precision
If the static sample fluid is heated by heat transmitted from the lamp during oxidation, then the oxidation reaction proceeds, but the temperature influence on TOC computation is especially high at conductivity between 0.1 and 1 μS/cm
Solution Approach 1:
The patent incorporates temperature sensors and implements temperature compensation in the TOC computation algorithm. The system continuously monitors temperature and adjusts the conductivity-to-TOC conversion based on the measured temperature, eliminating measurement errors caused by thermal effects
Solution Approach 2:
The patent introduces temperature compensation as an intermediary calculation step between conductivity measurement and TOC determination. This intermediary process corrects for temperature effects before the final TOC value is computed, ensuring accuracy despite temperature variations
4Reliability
If the excimer lamp is operated continuously, then oxidation can be maintained, but unnecessary radiation and heat generation occur after the oxidation reaction has stabilized
Solution Approach 1:
The patent implements periodic operation of the excimer lamp, switching it on only when needed for oxidation and turning it off when the reaction has stabilized. This periodic action maintains oxidation reliability during measurement while eliminating unnecessary energy loss during stable operation
Solution Approach 2:
The system dynamically adjusts the excimer lamp operation based on the oxidation reaction state. The lamp is activated when oxidation is needed and deactivated when stability is achieved, making the system adaptive rather than static, thereby reducing energy waste
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 enhances sensitivity and accuracy, extends the device's operational lifetime, reduces environmental impact, and improves safety, enabling precise detection of TOC levels down to 1 ppb in ultrapure water with reduced unnecessary radiation and heat generation.
Implementation Method 1
an oxidation of the organic carbon contained in a sample fluid and a subsequent detection of the resulting CO2 (carbon dioxide) in the sample fluid. The oxidation of the sample fluid can be effected by UV-radiation
Implementation Method 2
The amount of CO2 is determined by measuring the conductivity of the sample fluid
Implementation Method 3
the static sample fluid is generally heated by the heat transmitted from the lamp but could be also cooled by the influence of static air surrounding the oxidation chamber. The influence of the temperature on the TOC computation is especially high at a conductivity between 0.1 and 1 μS/cm
Data Source
AI summary
A device for measuring the total organic carbon content (TOC) of a sample fluid comprises a measuring cell (2) defining a volume (3) for containing a sample fluid and an excimer lamp (20) arranged to cause an oxidation reaction of the sample fluid by emitting radiation onto the sample fluid in the volume (3). A pair of electrodes is arranged to measure the conductivity of the sample fluid during the oxidation reaction and at least one temperature senor (31) is arranged on the measuring cell (2) to measure a temperature that is related to the sample fluid. The total organic carbon content (TOC) of the sample fluid is determined on the basis of the measured conductivity compensated by the temperature related to the sample fluid.