Model 450i Hydrogen Sulfide - Sulfur Dioxide Analyzer
Volume III, Edition 2
The Thermo Scientific™ Model 450i Hydrogen Sulfide–Sulfur Dioxide analyzer operates on the principle that H2S can be converted to SO2. As the SO2 molecules absorb ultraviolet (UV) light and become excited at one wavelength, the molecules then decay to a lower energy state emitting UV light at a different wavelength. The pulsing of the UV source lamp serves to increase the optical intensity, whereby a greater UV energy throughput and lower detectable SO2 concentration are realized. Consider these 5 tips and tricks when operating a 450i Hydrogen Sulfide—Sulfur Dioxide analyzer:
Rebuild your pump
It’s recommended to rebuild your pump before they become less effective and trip the flow or pressure alarms. Typically this should be done every 6 months to a year. For detailed instructions see the iSeries Vacuum Pump Technical Note
Perform a pre-calibration
If you are in the market for a CO2 analyzer, it's helpful to know the Thermo Scientific Model 410i Carbon Dioxide Analyzer is available in a standard or a high level range and the two versions are not interchangeable. The analyzer uses an internally stored calibration curve to accurately linearize the instrument output over any range up to a concentration of either 10,000 ppm (standard range) or 25% (high level range). Additionally, when placing your order, be aware the letter D in the Model code stands for dilution and letter E stands for extractive.
Let the mirrors be
DO NOT attempt to clean the mirrors in the mirror housing assembly. These mirrors do not come in contact with the sample gas and should not be cleaned. Cleaning the mirrors can damage them. If you need to replace the entrance mirror or mirror block housing due to UV degradation, see Mirror Housing Technical Bulletin for details. Please note the Model 450i utilizes the same mirror part numbers as the Model 43i.
What is the optical span test?
One of the built-in diagnostic tools of the Model 450i Hydrogen Sulfide—Sulfur Dioxide analyzer is the Optical Span test. The optical span test screen is used to turn the optical span test LED on or off, and displays an SO2 concentration reading. Within the fluorescence chamber is a light emitting diode (LED) which may be used to simulate a particular concentration of SO2. Note: The flash lamp must be turned off prior to this test. It is designed to provide a quick and easy way of checking the optics and electronics for span drift or other problems.
Model 450i spare parts
To keep your system running and properly collecting data, it’s important to have spare parts on hand. We have developed spare parts kits to ensure maximum uptime of your Thermo Scientific instrument during its life cycle.