Wednesday, July 18, 2018

Process Refractometers Used in Industry

Process refractometer
Technician adjusts process refractometer in plant.
(Electron Machine)
Process refractometers provide the analysis to quickly, reliably, and very accurately identify a sample and determine it's concentration and purity levels. They measure the refractive index and temperature of flowing liquids, and apply mathematical functions to determine the concentration of dissolved solids.

Part physics, part material science and part chemistry, refractometry is the process which measures the composition of known substances by means of calculating their respective refractive indexes (RI).  Light bends and changes velocity as it travels from one media into another through the media interface. When light traveling through air enters liquid, the light rays change direction by an amount determined by the liquid's density. RIs are evaluated via a refractometer, a device which measures the curve, or refraction. The
unitless number given by the refractometer, usually between 1.3000 and 1.7000, is the RI. The composition of substances is then determined when the RI is compared to a standard curve specific to the material of the substance. Standard tables are available that correlate RI to a variety of materials. These same tables also correlate RI to varying concentrations of particular liquid media at a particular temperature. Take corn syrup for example. Different refractive indexes are observed for different corn syrup samples of different concentrations. Therefore, by using a process refractometer to observe the RI of a particular corn syrup sample, a determination of the concentration of that particular sample can be made. By referring to the table or scale that correlates the RI to concentration at a particular fixed temperature, liquid concentration can be determined.

Common industrial refractometer applications are:

Process refractometer
Process refractometer with flanged spool adapter.
(Electron Machine)
  • Calculating amount of sugar dissolved in juices and beverages.
  • In commercial food applications such as juice production or tomato processing, refractometers are used to measure degrees Brix (the Brix scale relates refractive index to sugar concentration, and is a key way to maintain consistency).
  • In the pharmaceutical industry, process refractometers are used to monitor and control concentration levels during supersaturation, a critical process in crystallization.
  • In pulp and paper production, process refractometers for measuring dissolved solids in black and green liquor during the chemical recovery process.

Equipment manufacturers have developed numerous refractometer configurations tailored to specific each use and application. Each has a set of features making it the advantageous choice for its intended application. Product specialists are invaluable sources of information and assistance to potential refractometer users seeking to match the best equipment to their application or process.

For more information on industrial refractometers, contact Alliance Technical Sales by visiting or by calling 630-321-9646.