Concentration Measurement Using Temperature-Corrected Wavelength Selection
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Solution Overview
Problem
Concentration measurement accuracy is compromised due to varying absorbance characteristics of fluids with temperature changes, even with the same gas species, in conventional concentration measurement devices.
Innovation Solution
A concentration measurement method using a device with a measurement cell, light source, photodetector, and arithmetic circuit that calculates fluid concentration based on the Lambert-Beer law, incorporating a temperature sensor to correct for temperature-dependent absorbance changes, with incident light wavelengths outside the 220-240 nm range for fluids like trimethylaluminum, and using a two-core type concentration measurement device to minimize stray light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional concentration measurement devices use fixed wavelength light detection, then the device structure remains simple, but measurement accuracy deteriorates when fluid temperature varies
Solution Approach 1:
The patent applies parameter changes by selecting a specific wavelength range (250-300 nm) for incident light that is less sensitive to temperature-induced molecular structure variations. This wavelength parameter selection allows accurate concentration measurement across varying temperatures without requiring complex temperature compensation mechanisms, thus improving measurement precision while maintaining relatively simple device structure.
Solution Approach 2:
The patent implements feedback by using the detected absorbance signal to calculate concentration through the Lambert-Beer law, and by incorporating temperature sensing to account for temperature effects on absorbance characteristics. This feedback mechanism enables the system to maintain accurate concentration measurements despite temperature variations in the fluid.
2Illumination intensity
If light wavelength in the range of 220-240 nm is used for measurement, then absorbance signal strength is maximized, but measurement accuracy deteriorates due to temperature-dependent molecular structure changes
Solution Approach 1:
The patent changes the wavelength parameter from the conventional 220-240 nm range to 250-300 nm range. This parameter change reduces sensitivity to temperature-induced molecular structure variations while still providing sufficient absorbance signal for accurate concentration measurement, thereby resolving the contradiction between signal strength and measurement precision under varying temperature conditions.
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 enables more accurate concentration measurement of fluids whose molecular structure varies with temperature, improving measurement precision by accounting for temperature-induced changes in absorbance characteristics.
Implementation Method 1
a light with a predetermined wavelength is incident from a light source through an incident window on a measurement cell in which a fluid flows
Implementation Method 2
the absorbance is measured with a light-receiving element by receiving transmitted light passing through the measurement cell
Implementation Method 3
The concentration of the fluid can be calculated according to the Lambert-Behr's law from the measured absorption
Data Source
AI summary
A concentration measurement method is performed using a concentration measurement device comprising: a measurement cell for flowing a fluid to be measured; a light source for generating light incident on the measurement cell; a photodetector for detecting light emitted from the measurement cell; an arithmetic unit for calculating the absorbance and concentration of the fluid to be measured based on an output of the photodetector; and a temperature sensor for measuring the temperature of the fluid to be measured. The concentration measurement method includes: a step of flowing a gas whose molecular structure varies with the temperature as the fluid to be measured in the measurement cell; a step of making light of a wavelength absorbable by the fluid to be measured to be incident from the light source to the measurement cell; a step of measuring the intensity of light emitted from the measurement cell by the photodetector; and a step of calculating the concentration of the fluid to be measured based on the temperature and the output of the photodetector measured by the temperature sensor.