Gas Analyzers
UVDOAS Gas Analyzer
Posted: February 6, 2017 at 6:39 am / by / comments (0)
Ultraviolet Differential Optical Absorption Spectroscopy Gas Analyzer(UV DOAS)
Vasthi Instruments UV DOAS Gas Analyzer for Sox, Nox and other emission monitoring as per CPCB Guidelines.
The module uses the long optical path UV DOAS technology. Its optical technology platform consists of light source, gas chamber, optical and spectroscopic (including diaphragm, holographic grating, linear array detector) and other optical components.
The same gas has different absorption in different spectral band, the absorption of different gases in the same spectral band has superposition effect. Through the analysis of continuous spectrum, a variety of gas can be measured at the same time. The holographic grating is used for light splitting of light absorbed by gas to be measured, sensor array is used to convert the spectral optical signals into electrical signals, after obtaining the continuous absorption spectra of medium, and a variety of gas can be measured at the same time.
Differences between Different Technologies:
| NDIR Technology | FTIR Technology | UV Fluorescence+ Chemiluminescence | UV DOAS Adopted Technology |
| I. Low cost | I. High cost | I. High cost | I. Low cost |
| II. Measure few components:Generally, the single gas chamber can only measure one kind of gas | II. Measure over 10 components, which is the greatest advantage | II. Measure few components, Different components with different measurement principle. | II. The single gas chamber can measure 3-5 components |
| III. Precious gas chamber, high cost and complicated replacement | III. Precious gas chamber, high cost and complicated replacement | III. Precious chamber, high cost and complicated replacement | III. Strong gas chamber low cost and convenient replacement |
| IV. Have the optical moving parts, with low reliability | IV. The interferometer is an optical moving part | IV. No optical parts | IV. Adopt the full spectrum electronic scanning and have no optical moving parts |
| V. Single or dual wavelength measurement; easy to be affected by the interfering gas | V. Full infrared spectrum measurement, and have no effect by the cross interference | V. Very sensitive to some interference , such as background fluorescence and quenching effect, etc. | V. Full ultraviolet spectrum measurement, and have no effect by the cross interference |
| VI. Fast response, low measurement accuracy and large drift | VI. Restricted by the scanning time; slow response, high measurement accuracy and small drift | VI. Fast response, Background light resulting in poor results of stability and reproducibility; high measurement accuracy and large drift | VI. Fast response, high measurement accuracy and small drift |
| VII. High requirements for the measured gas, no dust and low dew point | VII. High requirements for the measured gas, no dust and low dew point | VII. High requirements for the measured gas, no dust and low dew point | VII. Low requirements for the measured gas, applicable to the operating environment with dust or high humidity |
| VIII. Adopt the continuous light source, with the service life of thousands | VIII. Adopt the continuous light source, with the service life of thousands of hours | VIII. Adopt the continuous light source, with the service life of thousands of hours | VIII. Adopt the pulse light source, with the service life of 10 years |
Comments (0)