Showing posts with label K-Patents. Show all posts
Showing posts with label K-Patents. Show all posts

Tuesday, August 11, 2020

Sanitary Process Refractometers for Food, Beverage & Dairy Industries: The Vaisala K-PATENTS PR-43A

Vaisala K-PATENTS® PR-43A Models PR-43-AC, PR-43-AP, PR-43-APT

Vaisala K-PATENTS® Sanitary Process Refractometers PR-43-AC for hygienic installations in small pipe line sizes of 2.5 inch and smaller; PR-43-AP for hygienic installations in large pipes, tanks, cookers, crystallizers and kettles and for higher temperatures up to 150°C (300 °F); and the PR-43-APT for flush mounting installations in cookers, cooling crystallizers and other vessels that have scrapers or mixers.

Sanitary Refractometer Applications:

Extraction, evaporation, brewing, distilling, sugar dissolving, blending, filling. Alcohol, rum, whiskey, brandy, vodka, molasses, liquors, cider, alcoholic beverages, pre-mixed liquors. Beer and malt beverages, wort, cut beer, root beer. Juices, blended vegetable and fruit juices and nectars, still drinks, vegetable and juice concentrates, iced tea and coffee, instant coffee and tea. Soft drinks, energy and sport drinks, beverage base. Wines, grape must.

Sanitary Refractometer 3A Approval:

The Sanitary refractometer PR-43-A is Sanitary 3-A approved to meet the highest hygiene requirements of food production. The 3-A Symbol assures that the Sanitary Refractometer

PR-43-A conforms to 3-A Sanitary Standard Number 46-04 for Refractometers and Energy-Absorbing Optical Sensors for Milk and Milk Products and it has passed the independent Third Party Verification inspection for 3-A Symbol authorization.

For more information about Vaisala K-PATENTS products in New New England, contact Piping Specialties, Inc. / PSI Controls. Call them at 800-223-1468 or visit their web site at

Monday, July 20, 2020

Refractometer Application in Kraft (Sulphate) Pulp Process: Digester Washing Zone and Blowline

Refractometer Black Liquor


The first operation in the Kraft pulping process involves the extraction of cellulose from wood by dissolving the lignin that binds the fibers together. This is done in a strongly alkaline solution.

This process is known as cooking. After the wood pulp is obtained, it is washed and bleached to obtain the fibrous product.

To optimize the pulp chemical consumption and water usage, the black liquor concentrations have to be measured before and after washing.


Incoming wood is debarked and chipped to an optimal size to minimize fibre damage, and to maximize the impregnation with the cooking liquor. The chips and the cooking liquor are fed into a large vessel known as digester. The pulping reaction takes place under pressure and at a high temperature.

After cooking, the pulp passes through a blow line to the blow tank and then to a washing section. The diffuser washers separate the black liquor from the fibers by washing them with a washing liquor or water. The products from the fiber line are a clean pulp, and a diluted black liquor known as weak liquor.

The washed pulp is then screened before it is sent to the bleaching plant, and the weak black liquor passes from the washing section to the chemical recovery process.

Instrumentation and installation

The K-Patents SAFE-DRIVE Refractometer PR-23-SD measures in real-time the Total Dissolved Solids (TDS) content in black liquor.

K-Patents PR-23-SD
The K-Patents refractometer is installed in-line in different points after the digester. TDS measurement
in the blow pulp suspension after the digester enables monitoring of the diffuser operation. Together with other measurements (e.g. filtrate and flush liquor) this provides the mill with the ability to control the performance of the washing zone in the digester. In addition, TDS measurement in the blow line allows the performance of the digester to be monitored, ensuring that it yields the correct concentration. The combination of these measurements facilitates continuous calculation of the mass balances of the digester.

The refractometer’s measurement is unaffected by bubbles, particles, consistency, flow, ion changes, pH, temperature, pressure, color or turbulent flow. The measurement surface is periodically cleaned using an integrated and automatic prism cleaning system.

The K-Patents PR-23-SD 

Black liquor concentration measurement with the SAFE-DRIVE process refractometer helps to increase washing efficiency, obtain a consistent pulp quality, reduce bleaching chemical consumption and environmental load, and increase evaporation efficiency.

For more information, contact PSI Controls (Piping Specialties, Inc.). Call them at 800-223-1468 or visit their website at

Thursday, June 18, 2020

Process Refractometers Improve Production and Quality of Phosphoric Acid Production

Phosphoric Acid Production
Phosphoric acid is an important product used in industrial applications such as the manufacture of agricultural phosphate fertilizers, detergents, pesticides, metal coating, etc. Due to its non-toxic and mildly acidic nature, phosphoric acid is also used in other applications including food flavoring, soft drinks, pharmaceuticals, dental products, cosmetics, and skin care products.

Phosphoric acid is produced by mining the naturally occurring phosphate rock and processing it via a wet process or a thermal process. The concentration of the acids during the wet process can be measured inline with the process refractometers, such as those manufactured by K-Patents.

To learn more about where and how these refractometers are used in wet process phosphoric acid production, visit the PSI Controls web page. 

Piping Specialties, Inc. / PSI Controls

Wednesday, October 16, 2019

Inline Process Refractometers in Beer Brewing

Inline Process Refractometers in Beer Brewing


PR-43-AThe first step in the beer brewing process is the preparation of malt grains. The extract received fromthe processing of this raw material is called wort. The second step is fermentation by yeast. The last steps are conditioning and final filtration. After filtration, the beer is ready for bottling.

Instrumentation and Installation

Vaisala K-PATENTS® Sanitary Process Refractometer PR-43-A is used at many stages of the brewery process to determine in real-time and accurately the concentration of dissolved solids. The refractometer takes an optical measurement of the refractive index of a solution and its output can be calibrated in Plato, Brix, Balling, gravity or density, depending on the preference of the brewery.
The Sanitary Refractometer is available with 3-A Sanitary and EHEDG certifications and it withstands CIP/SIP cleaning and rinsing of the facilities.

1. Mash tank

Mashing is the process of mixing the crushed malt with very hot water. In this process, the malted grain breaks down to create enzymes, which become active when exposed to water at a specific temperature. These active enzymes convert the starches into sugars. The resultant sugary liquid is known as the wort. Mashing is a crucial step as it determines the final structure of the beer.
In the mashing stage, the refractometer is used to measure the concentration of the mash in water at the outlet pipe to maintain a consistent concentration. Automatic prism wash with steam or high-pressure hot water is recommended for this application.

2. Lauter Tun

Lauter tun is a vessel used to separate the extracted wort from the spent grain. The solids in the lauter tun are rinsed with water to separate the clear liquid wort from the solids. The liquid concentration gradually decreases during the rinsing.
At the lauter tun the refractometer’s output signal is used to detect the shut-off point for rinsing, thus preventing excessive use of water. Automatic prism wash with steam or high-pressure water is recommended for this application.

3. Wort Boiler (Brew Kettle)

In the wort boiler the wort is pasteurized, and its flavor is adjusted by the addition of hops (or other flavors such as ginger or molasses). The brew is boiled until a certain strength or gravity is achieved. This step is essential for the quality of the final beer.
The refractometer is installed directly on the wort boiler to measure the wort strength/gravity. It provides an instant feedback when the wort has reached its required strength. No by-pass arrangements are required. The purpose is to eliminate sampling, optimize the boiling time, and to improve beer consistency and quality. Automatic prism wash with steam or high-pressure water is recommended for this application.

4. Hot Wort from Boiler to Whirlpool

The refractometer is installed in the wort boiler outlet to monitor the quality of the wort. Before the wort goes on to the next stage, solids are removed from the liquid by using a whirlpool. All hops and other solids are forced to the center of the whirlpool. When the whirlpool is stopped, the solids settle at the bottom, forming a fairly solid central cone. The liquid can then be drained off.

5. Chilled Wort from Heat Exchanger

The wort is cooled down to the correct temperature for the yeast. The refractometer is used for quality control, by a way of measuring the cold wort before it enters the fermentation process. This is an alternative measurement to point 4.

6. Fermentation

Fermentation starts when the yeasts are added to the wort. The yeast converts the sugars and amino acids into alcohol and carbon dioxide. The fermenting reaction is slow, and its progress must be monitored to determine the end point.
The spent yeast settles at the bottom of the tank and is frequently removed. This process helps to clarify the beer.
In fermentation, The refractometer continuously detects the changes in refractive index because of the conversion of sugars into alcohol. This allows monitoring the conversion rate, the degree of fermentation and provides an indirect measurement of the alcohol volume (%) for determining the end point (see also application note Alcoholic Fermentation).

7. Filtering

After fermentation, the beer is let to rest, so that the suspended dead yeast settles at the bottom. This conditioning process helps the maturing of the beer. The refractometer provides a quality control measurement for the wort filtering output.

8. Packing and Interface Detection

Packing is typically done by filling the beer into bottles or aluminum cans via a filling machine. Some brewers may use the same filling line for different products. In this case a Clean-In-Place (CIP) operation is required between the filling of each product.

At the filling line, the refractometer instantly detects the product-to-product and product to-CIP cleaning interfaces in bottling. The refractometer output signal can be utilized for quality control monitoring, and to ensure correct product-to-bottle selection and a product quality within specification.

If the same filling station is used for different products, the refractometer can be used for automated monitoring and controlling of the CIP cleaning process, allowing products to be switched freely. This results in increased productivity, without compromising the end product’s quality and safety.

For more information about the use of process refractometers, contact Piping Specialties, Inc. / PSI Controls by calling 800-223-1468 or visit their web site at

Reprinted with permission from Vaisala/K-Patents.

Wednesday, June 5, 2019

Guide to Industrial Refractometer Applications

Industrial refractometer
Industrial refractometer
As a general rule, refractometers measure the concentration of any dissolved material in a liquid. A typical measured medium is a binary solution, but it can also be a mixture of more than two components. In multi-component solutions this is a checksum; if one of the components is wrong, the overall refractive index value changes.

The potential applications in different industries are countless. Although the manufacturing process, environment and processing medium vary from industry to industry, all basic unit operations and control strategies are roughly the same despite of the end product.

Applications discussed in the application guide include:
  • Crystallizers
  • Reactors
  • Evaporation
  • Ultrafiltration
  • Reverse Osmosis
  • Spray Dryers
  • Dissolving Tanks
  • Solid / Liquid Extraction
  • Cooking Processes
  • Ion Exchangers
  • Absorbers and Wet Scrubbers
  • Distillation
  • Interface Detection

For more information about the application of industrial refractometers in manufacturing processes, contact Piping Specialties / PSI Controls by calling 800-223-1468 or by visiting their web site at

Saturday, June 30, 2018

Best Practices Document for the K-Patents PR-23-SD Safe-Drive™ Process Refractometer

K-Patents PR-23-SD Safe-Drive
This document is intended for individuals installing, commissioning, operating, and/ or servicing the Safe-DriveTM Process Refractometer PR-23-SD, generation 2.1 model. The purpose of this document is to provide a quick guide for the abovementioned tasks in the form of K-Patents recommended best practices.

This document is intended for PR-23-SD applications that have a steam wash system (typical application for black liquor) and applications that have high pressure water wash system (typical application for green liquor).

NOTE: These instructions are for quick reference only. For more thorough guidance, please refer to the K-Patents user manual and documentation that came with your equipment.

Review the embedded document below, or download a PDF version of Safe-Drive™ Process Refractometer PR-23-SD Generation 2.1 Best Practices here.

Monday, May 21, 2018

Refractometer Application for Wet Spinning of Alginate Fibers

Refractometer used for
wet spinning of alginate fiber.
Alginates are biopolymers extracted from brown algae species such as seaweed. Extraction is performed from the harvested material by treatment with aqueous alkaline solutions. The extract is then filtered and the alginate salt is precipitated by the addition of calcium chloride or an acid. After purification, drying and milling, a water-soluble sodium alginate powder is produced. Alginates have found a variety of uses in different industries because of their unique properties. These materials have been extensively used in pharmaceutical applications as they are gel forming, non-toxic and highly absorbent.

The document below illustrates the use of industrial refractometers in the processing of Sodium Alginate. You can also download the full PDF of "Wet Spinning of Alginate Fibers" here.

Tuesday, February 27, 2018

Industrial Process Refractometers

Process refractometer
Process refractometer
The ultimate focus of industrial refractometry is to describe the percentage of certain compounds in a final product. Refractometry, a combination of physics, materials, and chemistry, is the process which measures the composition of known substances by means of calculating their respective refractive indexes (RI). RIs are evaluated via a refractometer, a device which measures the curve, or refraction, resulting when the wavelength of light moves from the air into and through a tested substance. 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.

Common examples of industrial refractometry uses are measuring the salinity of water to determine drinkability; calculating the dissolved solids in liquor processing in pulp and paper production;  figuring beverages’ ratios of sugar content; and understanding the hydrocarbon content of motor fuels. Regarding pulp and paper, refractometry scrutinizes content of compounds in black and green liquor processing. Regarding food, refractometry has the ability to measure the glucose in fruit during the fermentation process. Because of this, those in food services know when fruit is at peak ripeness and, in turn, also understand the most advantageous point in the fruit’s “lifetime” to put it on the market.

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

Sunday, November 12, 2017

Instructional Video: Inserting K-Patents Generation 2.1 SAFE-DRIVE™ Process Refractometer PR-23-SD

This video is intended for individuals installing, commissioning, operating, and/ or servicing the K-Patents Safe-DriveTM Process Refractometer PR-23-SD, generation 2 model. The purpose of this video is to provide a quick guide for the above mentioned tasks in the form of K-Patents recommended best practices.

K-Patents SAFE-DRIVE™ design allows for safe and easy insertion and retraction of the sensor under full operating pressure without having to shut down the process.

Below the video is the document "Best Practices for the Safe-DriveTM Process Refractometer PR-23-SD Generation 2" for your convenience.

For more information, visit or call 800-223-1468.