Complete UV/VIS/NIR Systems 
Liquids and Gases Worldwide Sales and Support
Liquids and Gases Worldwide Sales and SupportComplete UV/VIS/NIR Systems Liquids and Gases Worldwide Sales and Support
Liquids and Gases Worldwide Sales and Support
ChemView SMART Photometer
NEMA 4X General Purpose |
Class 1, Divisions 1-2 Groups B-D |
ATEX II 2 EEx d IIC T6 |
ChemView was designed for those liquid and gas applications where a spectrohotometer and chemometric modeling are overkill. A surprising number of applications can be simplified to a handful of wavelengths. A photometer is a lower cost alternative for long-term success at the plant-level. Consider a photometer where partial least-squares PLS chemometric models show less than five factors are needed. This encompasses a great variety of chemical measurements. Furthermore, photometers typically operate with multiple linear regression (MLR) or simple least-squares (LS) prediction models that can be generated in common spreadsheet programs by most instrument specialists or process engineers. As such they do not require Ph.D. chemometrics specialists for model maintenance. The models can be maintained at the plant level.
ChemView revolutionized process filter photometry since its introduction in 1997. Its main advantages are:
- Compact size starting at 6 x 8 x 10" (NEMA)
- 5 analyzing and 1 reference wavelength
- StabLamp stabilized light source with optical feedback
- Extensive thermal stability for best analytical precision
- Very low photometric drift of 1-2 mAU/2 weeks (equivalent to ±25 ppm water in a 2 cm optical path at 1900 nm)
- NO-MOVING-PARTS for low maintenance (no spinning filter wheel bushings to replace)
- Simultaneous measurement of all wavelengths to reduce process "noise", ensuring that your reference wavelength relates EXACTLY to the analyzing wavelengths
- Simultaneous measurement of VISIBLE color and NIR composition (e.g. yellowness and acid number in resin melts)
- SMART diagnostics to minimize guesswork in troubleshooting
- Can be up to 80 m from the sample cell using fiber optics, eliminating the need to pump explosive or dangerous liquids (phenol, HCN) or gases (Cl2, phosgene) into the analyzer
- Can accept signals from RTD temperature sensors or pressure transducers to correct for variations in sample conditions
ChemView's patented design is shown below. A tungsten halogen lamp is selected to match the size of the optical fibers. It is stabilized by a detector in an optical feedback loop (a pulsed Xe lamp is used for UV applications). Light is transmitted in a fiber optic cable to the sample cell, where it interacts with the sample. The remaining light is transferred back to the analyzer by a second fiber optic cable. It is divided among (up to) 6 detectors using beamsplitters and then passes through spectrally narrow (6-15 nm wide) optical filters. We use Si and InGaAs detectors, such that low light levels are not a problem. The detectors produce a voltage that is converted to log(voltage). The log(voltage) at each analyzing wavelength is subtracted from the log(voltage) at the reference wavelength, resulting in a voltage equivalent to units of spectroscopic absorbance. The reference wavelength is generally chosen in a spectral region that does not change with changing chemistry. 1 Volt = 1 Absorbance Unit or AU. From this point in the circuitry, ChemView is now an absorbance machine. Absorbance is proportional to chemical concentration in most instances. The powerful microprocessor applies the calibration coefficients to the absorbances, including sample pressure or temperature if needed, sums the results and outputs the predicted concentration. The output is displayed on the LCD screen, scaled and transmitted to the process control computer with self-powered, isolated 4-20 mA analog signals.
As shown at the top of the page, ChemView can be supplied for NEMA 4X general purpose environments and explosion-proof in C1D1/2 or ATEX enclosures.
ChemView's diagnostic features with fault alarms are extensive, helping the instrument specialist to determine:
- lamp replacement
- window fouling
- fiber breakage
- sample cell failure
- intermittent cloudiness or turbidity
If there are no system faults, ChemView can further help in determining if the sample is an "outlier", that is, it does not "fit" within the calibration model. ChemView optionally has a patented chemical outlier detection (OutlierDetect) capability that can be trended or alarmed if the calibration uses 2 or more analytical wavelengths.
Lastly, ChemView can be provided with VirtualView, where an operator has access to nearly all menus, output scalings and calibration coefficients on a remote PC via local area network. This save time in sending an instrument specialist to another building to check a specific reading on the LCD display or upgrading the prediction model with new coefficients.
Specifications
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Enclosures |
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Dimensions |
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Certifications |
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Purges |
Expo-Safety Systems, continuous flow sub-miniPruge (1ZCFSS1S). Intrinsically safe switch closure and pneumatic "winkie" fo purge loss. 1/2" NPTF purge fitting. Purge vent orofice is Size 1 (for 0.4 cfm; 10 L/min). Allow 6 min. purge cycle (min. 4 volumes) prior to power up |
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Purge Gas |
110 p.s.i. clean, dry compressed air or inert gas |
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Fiber connections |
SMA 905 400 - 600 micron (core) |
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Detectors |
Max. 5 analyzing and 1 reference
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Filters |
10 nm FWHM for UV/VIS, 15 nm for NIR typical. 4 OD out-of-band blocking |
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Light Source |
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Wavelength Drift |
0.1 nm with Si detector 0.2 nm near 1450 nm with InGaAs detector |
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Photometric Drift |
<2 mAU with ±5ºC variation (±2 to 3 mAU with Xe) 0.2 mAU/ºC at 0 AU typical <2 mAU over 2 weeks |
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Photometric Noise |
<1 mAU (3 mAU with Xe source) |
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Outputs |
4 4-20 mA isolated, self-powered. 2 4-20 mAU additionally optional for a total of 6. |
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Environmental |
10 - 40 ºC, 10-90% rel. humidity (non-condensing) |
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Power |
110 - 240 V AC, 50-60 Hz, 70 VA (24 V DC, 2.1 A optional) |