McNab Model HSB High Sensitivity Clarity Analyzer |
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Click to enlargeModel HSB-XP (Explosion Proof) |
Center-of-pipe,
real-time measurement of suspended solids and clarity in process liquids.
A nephelometric particle measuring instrument, self-correcting for variations in illumination, color & fouling of optical surfaces. Related Technical Papers/News Releases: |
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How It WorksScatter is the effect particles have on a light shining through liquid. Typical engineering units are PPM (parts per million), NTU, EBC, JTU and others. In a scatter analyzer, light is collimated in a liquid, and the light scattered (by reflection, etc.) is proportional to the concentration of particles. The HSB measures light scatter at a right angle to the incident light. This has become an international standard, accepted by the EPA in the United States, the EBC in Europe and other authorities The Model HSB consists of a flow cell unit and the control/indicator unit. The unique 4-chamber design isolates scatter, transmitted and trapped stray light. The flow cell includes:
The indicator/control cabinet contains the modular electronic circuitry necessary to process signals from the photo-sensors to provide readings in the required units, to display those readings, to input desired set points, to indicate alarm levels, to operate relays and to provide self-diagnostics. From Light Beer to Coal Slurry…McNab Clarity Analyzers measure suspended solids in process liquids with:
No Standardization RequiredThe HSB achieves measurement stability of 0.1% per year, allowing maintenance-free operation. This is made possible by two critical matched signal verifying modules (SVMs), each with 100-megohm input impedance. These SVM’s eliminate drift, so there is no need for constant restandardization. SVM's also correct for any variation in sensor cable length, so nearby electric interference does not affect operation, even at cable distances of 600 feet (180m). Built-in Zero StandardThe unique built-in zero standard can be used at any time to verify standardization, even when the process is operating. Simply press the test button, and the system verifies that actual standardization has been maintained; no drift has occurred. No down time or removal is needed. High-Sensitivity Measurement In Problem LiquidsNew high technology optics and UV-enhanced sensors deliver 1,000 times more sensitivity than was possible just a few years ago. The HSB uses this dramatic improvement to measure suspended solids in "problem" liquids like dark stout and orange juice. Complete Color CompensationColor is "dissolved" in a liquid. Color does not scatter light, but it will attenuate light, interfering with accurate particle measurement. To prevent color interference, the Model HSB measures light attenuated by color and completely adjusts for this interference. The result is accurate, stable measurements without moving parts or adjustments. Center-Of-Pipe MeasurementThe ideal scatter measurement is made in the center of the actual process pipe. Near the pipe wall, in a by-pass pipe or in a slipstream, scatter particles will settle out because minimum velocity is not maintained. To eliminate this problem, the HSB measures only in the high velocity region in the center of the pipe. This is essential for high accuracy measurement and can yield a 2:1 improvement in accuracy. Extended-Life Light SourceOptical lamp life has been extended to an average of five years by use of optional improved lamp control circuitry. This makes a truly maintenance-free system. High Sensitivity For Ultra-Clean LiquidsMeasurement of liquids, like WFI and ultra-pure water, requires high sensitivity measuring geometry. The HSB uses a new, proprietary light trap chamber to give a 3:1 improvement in sensitivity over the previous state of the art. This chamber configuration traps stray light that would otherwise block high-sensitivity measurement, as in other designs. About McNabSpecifications
A90-85B Rev B |
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