The new OE750 OES analyser from Hitachi High-Tech shows what’s possible with an analyser of this class. It has the performance usually only seen in much more expensive instruments, such as analysing all elements in metal down to astonishingly low ppm.
But how can it deliver this level of performance at such an accessible purchase price? And how have we cut the analyser’s running costs too? It’s all in the technology:
The optics are core to the operation of the OE750, and this new optical concept, which has four patents pending, gives the analyser the best optical resolution in its class. This ensures you can detect everything you need to, even at ultra-low limits. The optics configuration within the OE750 have been completely re-designed. The volume of the housing is relatively small, reducing start up time, ensuring the instrument is ready to use much sooner. We have included more detectors and placed them on a single focal plane; this gives excellent resolution and clear presentation of results. And finally, the detector itself has been upgraded, which we’ll cover below.
Fundamental to reducing the cost of the analyser, yet improving performance, is the detector itself. We have used a new CMOS chip instead of the old type CCD detector. The CMOS chip has a higher resolution and improved pixel size, plus a higher dynamic range. This means that only one coated sensor can be used, where several CCD type sensors would typically be needed. And it’s this that keeps the cost of the analyser down, yet the performance on a par with much more expensive instruments. The CMOS type of detector also outperforms the older CCDs in terms of stability at low limits of detection – exactly what you need when analysing metals down to the ppm range.
One of the issues with standard OES instruments is the tendency of light intensities to degrade over time for wavelengths below 200nm, causing lack of resolution for some analyses. We’ve overcome this problem entirely by developing a mid-pressure argon purge environment that gives better stability and higher intensity even below 150nm. The system reduces the amount of argon needed and allows for use of an oil-free pump that is only in use for some of the time. Power consumption to the pump is reduced and maintenance and calibration intervals are greatly increased. This increases the instrument availability and reduces operating costs.
We’ve also redesigned the electrical spark discharge source. This part of the analyser traditionally used a lot of power to generate the spark, and any fluctuations in the power supply could change the spark characteristics, which could affect the reliability of the results. In the OE750 we decided to go back to the drawing board and design this from the ground up. We’ve increased the efficiency of the spark source, which means it uses less power and generates less heat. We’ve also included features that improve reliability and reproducibility of each spark – for example a 24V DC supply that isolates the spark from the local mains voltage, so fluctuations in the local supply doesn’t affect the performance of the analyser.
In the new design the spark-stand and optics are essentially one sealed unit. This is the best way to get consistently low detection limits and best performance over the wide wavelength range. This is also mandatory for the analysis of gases in metals such as nitrogen in steel with a detection limit at a level of 10 ppm. A sealed unit means air and particulates cannot enter the spark stand and optics area, ensuring minimal interference of the analysis. It also means that the distance between the entrance slit and lens is very short, vastly improving the light coupling. The housing is designed for optimal laminar flow of argon around the lens, again reducing the amount of argon needed. Plus the sealed unit reduces the need for maintenance, so you get more uptime AND better results.
This level of performance enables you to meet stringent specifications, detect tramp and trace elements in scrap, and verify incoming materials at the ultra-low limits that today’s metal industry demands.
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To find out more about how the OE750 gives you much more for your money, get in touch to book a demo.
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