Measurement
Refractive index
Liquid measurement with inline process refractometers Latest: Vaisala Polaris™ process refractometer product family
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Vaisala Polaris process refractometers are used for inline liquid measurements to enable efficient process control and industrial automation. They are stand-alone and smart devices that measure and indicate concentration units and diagnostic information. They provide 4-20 mA or Modbus RTU outputs to connect directly to the control system. All process refractometers can also be connected with the Indigo520 for process refractometers for physical user interface and expansion of features.
The Vaisala Polaris refractometers represent the latest, 5th -generation product line. Process refractometers became part of Vaisala in 2019, following the acquisition of K-PATENTS, a leading innovator with over 40 years of experience in designing and manufacturing industrial process refractometers to cater to a wide range of applications.
Our significant investments in research and development have earned us global recognition for delivering innovative, dependable, and top-quality products.
Accurate, drift-free measurements for liquid concentration
Vaisala Polaris process refractometers are widely utilized to determine liquid concentration or density. This measurement has been an important element in the processing industries for over a century. Our advanced digital refractometer technology can significantly enhance the performance of refining, manufacturing, and quality control operations.
Real-time concentration measurements obtained through our inline refractometers can be used as a valuable predictive tool for achieving optimal final concentration. A quick and accurate response is needed to optimize production. Cost reduction is possible by reducing the variation of mean average of the product concentration. The cost saving is related to the value of the component being measured.
Customer reviews:
“The measurement is reliable and stable despite of heavy membrane vibration.”
– Whey protein concentrate plant, New Zealand
“Our annual waste at filling line was million liters. Replacing volumetric flow and turbidity meters with in-line refractometers, helped us to cut the changeover time to a legal minimum of 5 min, reducing waste by two thirds.”
– Dairy, Europe
“Real-time process refractometer is a great alternative to titrators saving time and materials”.
– Pharmaceutical plant, Austria
Full system of Indigo520 transmitter and process refractometer
The Vaisala Polaris paired with the Indigo520 transmitter for process refractometers makes an impressive duo, offering compelling features to suit all users. Indigo520 enables data logging, prism wash control, adjustment of settings and measurement parameters, and Indigo service updates.
The Indigo520 for process refractometers offers versatile system connectivity by two selected analog or digital inputs for process refractometers and other Indigo-compatible probes, four configurable analog outputs to alarm relays, and Modbus TCP/IP digital protocol.
Completely digital measurement principle based on physics
The refractometer operates on the principle of critical angle measurement. Inside the refractometer, there is a light source, a prism, and an image detector. Light rays with varying angles are emitted to the prism and process interface. Rays with a steep angle are partly reflected to the image detector and partly refracted to the process. Rays with a low angle are totally reflected to the detector. The critical angle is the angle at which the total reflection begins.
The CCD camera inside the refractometer detects a bright field and a dark field corresponding to partly and totally reflected light, respectively. The position of the borderline between these fields indicates the critical angle, which is proportional to the refractive index and thus the solution's concentration. As the measurement principle is based on physics and the law of refraction, it is drift-free.
A built-in temperature sensor measures the temperature T on the interface of the process liquid. The sensor converts the refractive index nD and temperature T into concentration units. Vaisala Polaris process refractometer can indicate different scales, for example, Brix, liquid density or concentration by weight. The diagnostics program ensures that the measurement is reliable.
Learn more about the Refractive Index Measurement Principle (PDF) and the law of refraction.
Refractive Index measurement principle, critical angle measurement
Industries and applications
Process refractometers help to achieve desired product specifications with improved product quality while optimizing the process and saving on energy consumption, raw materials, water, steam, and chemicals.
Chemical
Inline concentration measurement of acids, alkaline solutions, alcohols, hydrocarbons, solvents, and various other solutions in chemical industry Measure changes in concentrations of liquid chemicals in the harshest conditions of chemical processing industry. See the typical processes and applications where the inline refractometer can be used for product quality and process control.
Food and beverage
Inline Brix, total dissolved solids, or other other liquid concentrations for dairy, whey, brewing, juices, soft drinks, meat and fish products, ingredients, and fruit and vegetables processing. Stable inline liquid concentration measurements for instant productivity and material gains, and simplified process operation. Learn more from the application examples.
Oil refining and petrochemical
Loading and unloading operations, sulfuric acid alkylation, amine gas treating, gas dehydration, and lube oil production Eliminate sampling, improve product consistency and operations safety and optimize the process with the help of Vaisala Polaris process refractometers.
Pharmaceutical and biotechnology
Active Pharmaceutical Ingredients (API) development and production, Pharmaceutical fermentation, Vaccine and penicillin production, Protein concentration and filtration The Polaris Process Refractometer provides continuous, accurate, and repeatable measurements to optimize R&D and production processes.
Pulp and paper
Black liquor, green liquor, brown stock washing, filtrates, and other liquids in chemical recovery line and fiberline Optimize processes in the pulp and paper industry
Semiconductor
KOH (Potassium hydroxide), H2SO4 (Sulfuric acid), HF (Hydrofluoric acid), NH4OH (Ammonium hydroxide), HCl (Hydrochloric acid), IPA (Isopropyl alcohol), EKC, CMP slurries, and others Real-time concentration monitoring of wet chemical processes, including wafer manufacturing, etching, and cleaning
Sugar
Cane and beet sugar crystallization control Inline process refractometer for advanced supersaturation control and ensuring fine crystal formation and growth. Learn how to optimize cane and beet sugar refining and milling processes to achieve substantial energy conservation.
Sweeteners
Total dissolved solids (TDS) measurement in the production of starch sweeteners and sugar substitutes such as glucose (dextrose), fructose glucose syrup, corn syrup, and sorbitol. Inline liquid concentration measurement for liquid and crystal sweeteners manufacturing. Learn how to use the inline process refractometer to optimize downstream processes and comply with tight final product specifications.
Wastewater and effluent monitoring
The Vaisala Polaris™ inline process refractometer enables continuous, real-time monitoring of dissolved solids in wastewater streams by measuring the refractive index of effluents. This immediate insight allows industries to detect elevated levels of dissolved contaminants as soon as they occur, supporting early intervention and prevention of process upsets or abnormal contaminant levels.
Evaporation process optimization
Integrating Vaisala Polaris™ inline process refractometers into your evaporation process delivers operational advantages and cost savings through improved energy efficiency, consistent product quality, and process stability.
Key benefits
Full measurement range
The refractometer works over the full measurement range of Refractive Index (nD) 1.3200 – 1.5300, which corresponds to 0-100 Brix. Optional measurement ranges available.
CORE-Optics
Built-in CORE-Optics element eliminates the risk of leakages and drifts.
Completely digital system
Color, bubbles, particles, flow, temperature or pressure changes do not affect operation or accuracy.
Withstands low and high process temperatures
Compact model -40°C...130°C (-40°F...266°F), probe model: 40°C...150°C (-40°F...302°F).
Temperature compensated measurement output
The refractometer has a built-in Pt1000 temperature sensor for fast process temperature measurement and automatic temperature compensation.
Compatible with CIP and SIP cleaning
The refractometer withstands CIP (clean-in-place) and SIP (sterilization-in-place) processes and cleaning and rinsing of facilities.
Highly accurate
The accuracy of the in-line measurement is comparable to the accuracy of the production laboratory. Read more from our accuracy statement here
Easy on-site instrument verification
The refractometers are delivered calibrated with NIST traceable standard Refractive Index liquids. This allows easy instrument verification within user’s own quality assurance system using standard liquids and a built-in verification procedure.
Easy installation
Installation in the main processing line or vessel directly or via variety of flow cells; no by-pass arrangements are required. Also in vessels with mixers or scrapers is possible. Engineered custom solutions available.
Maintenance-free
The refractometer requires no regular maintenance as there are no wear and tear components that would have to be changed regularly. This means a low cost of ownership.
Product approvals and certifications
All instruments are developed considering the industry specific regulations and safety aspects. Product approvals and certificates allow manufacturing and supply of products in compliance with ATEX, CSA, FM, IEC, CRN, KEMA, DEKRA AND SANITARY 3-A, EHEDG.
Smarter liquid concentration measurement
Vaisala Polaris™ process refractometers deliver accurate, drift-free liquid concentration data to optimize processes, improve quality, and save energy across industries.
Support material of the previous generations
Manuals, approvals, certificates, safety instructions, and videos
A question about your measurement
A specialist replies with the solution, the instrument and the service that fit.