Outdoor TDLAS Multi-Pass Cell Temperature Control
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Solution Overview
Problem
Existing systems for measuring NOx and SOx, precursors of fine dust, face challenges in maintaining accurate temperature control without vibration, especially when used outdoors, which affects the precision of tunable diode laser absorption spectroscopy (TDLAS) measurements.
Innovation Solution
A system comprising a laser unit, a multi-pass measurement cell with prism or tube-shaped design, and a jacket-shaped heat exchanging unit surrounded by a thermoelectrically controlled heating medium, which maintains constant temperature without generating vibration, using a peristaltic pump to circulate the heating medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional cooling system using a compressor is used, then temperature control capability is improved, but vibration is generated which affects TDLAS measurement accuracy
Solution Approach 1:
The patent removes the compressor from the cooling system and replaces it with a thermoelectric element-based cooling mechanism. This extraction of the vibration-generating component (compressor) eliminates the source of vibration while maintaining temperature control capability through solid-state thermoelectric cooling.
Solution Approach 2:
The patent replaces the mechanical compressor-based cooling system with an electrical thermoelectric element-based system. This substitution eliminates moving parts and mechanical vibration while achieving the same temperature control function through the Peltier effect.
2Temperature
If a pump for transmitting heating medium is installed at a long distance, then temperature control is improved, but vibration from the pump disturbs accurate measurement of TDLAS
Solution Approach 1:
The patent removes the pump from the temperature control system and replaces it with a passive heat pipe-based heat transmission mechanism. This extraction eliminates the vibration source while maintaining effective heat transfer through phase change and capillary action in the heat pipe.
Solution Approach 2:
The patent replaces the mechanical pump-based fluid circulation system with a passive heat pipe system that uses phase change and capillary forces to transmit heat without moving parts, thereby eliminating vibration while maintaining temperature control.
3Productivity
If outdoor measurement is performed, then real-time measurement capability is improved, but temperature changes depending on seasons and day-night cycles affect measurement accuracy
Solution Approach 1:
The patent implements a proactive temperature control system that anticipates and compensates for environmental temperature changes before they affect the measurement. The thermoelectric element and heat pipe system actively maintain constant temperature in the measurement cell, preventing temperature drift that would otherwise occur due to outdoor environmental variations.
Solution Approach 2:
The patent changes the thermal parameters of the measurement system by implementing active heating and cooling capabilities through thermoelectric elements. This allows the system to dynamically adjust and maintain optimal temperature conditions regardless of outdoor environmental temperature changes.
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
Enables accurate, real-time measurement of NOx and SOx concentrations outdoors, maintaining precise temperature control regardless of environmental changes, thus ensuring accurate detection of fine-dust precursors without measurement errors.
Implementation Method 1
temperature control without vibration using a thermoelectric element
Implementation Method 2
a heat pipe, and a thermoelectric element, the heat pipe having a heat exchange portion that is in contact with an outer surface of the measurement cell
Implementation Method 3
Gases which influence an air environment absorbs mainly infrared ray
Implementation Method 4
a concentration and a temperature are obtained by comparing ratios between an initial laser intensity (I0) before transmission through a measurement region and a laser intensity (I) after the transmission through the measurement region where absorption occurs. This is performed based on the Beer-Lambert law.
Implementation Method 5
using a peristaltic pump to circulate the heating medium
Data Source
AI summary
The invention of the present application relates to a system for accurately measuring fine-dust precursors. Among apparatuses that measure concentrations of NOx and SOx which are precursors of fine dust by use of tunable diode laser absorption spectroscopy (TDLAS), an apparatus that can control a temperature of a measurement cell equipped with prism-type multi-passes by using thermoelectric elements without vibration is provided.