Vaisala Polaris™ PR53SD Process Refractometer

Pulp industry process optimization, black liquor, green liquor, brown stock washing, and other liquid concentrations in fiber and chemical recovery lines 

The Vaisala Polaris PR53SD Process Refractometer model is for the toughest process conditions in the pulp industry, measuring black liquor, green liquor, brown stock washing and other liquid concentrations in the fiber and chemical recovery lines. 

Stable and reliable measurement is in our core, and the process refractometer is retractable for service without process shutdown, minimizing downtime in the measurement. Therefore, the PR53SD instrument is for the critical and safety measurements in pulp mills.  

The modern, brand-new design on the SAFE-DRIVE retractor system enhances safety by integrating the process refractometer and the retractor as one, simple system. This prevents inadvertent errors in use and ensures that the isolation valve is closed before the instrument is removed. The system is easy to operate, consisting of only a few steps to insert or remove the process refractometer from pressurized process line with full operation ongoing. 

Unique in the world, Vaisala offers a retractable refractometer with a wash nozzle for green liquor. Same, accurate measurements inline also with high solids concentrations up to 85 % in black liquor. 

Advanced optical image analysis and diagnostics for prism wash

Advanced optical image analysis and diagnostics help users to quickly analyze wash performance. 

Get full data from the latest wash, along with comparable visual information, and adjust wash parameters accordingly. Fast and easy. 

Key benefits

Critical and safety measurements in pulp mills

The process refractometer design is in compliance with the BLRBAC Recommended Good Practice Safe Firing of Black Liquor in Black Liquor Recovery Boilers. 

Measure in all process conditions

Product measures reliably in various process conditions, including high heat, sticky process, rapidly changing process condition and with particles or fibers in the process.

New, safe and simple design for the SAFE-DRIVE retractor

Insert and remove from pressurized process line. The SAFE-DRIVE retractor design prevents inadvertent errors in use. 

Total dissolved solids, the only true measurement of organics and inorganics

Weak liquor and black liquor are a mixture of cooking chemicals and dissolved organic material. The RI measurement responds to all dissolved solids. Bubbles, foam, particles, suspended solids or fibers do not affect measurement. 

Plug & play to Indigo520

Expand features, including wash control, data storage, graphical interface, analog and digital interface by connecting to Vaisala Indigo520 transmitter. Convenient service with the Plug & play feature with minimized downtime should service be needed.

Customizable product with our Engineer to Order service

Big pipes, small pipes, spool pieces, washing system, spare parts, specific drawings? When one size does not fit all, Vaisala can tailor products to fit your specific needs.

Contact us for options! 

Pulp, paper and wood

Vaisala's inline dry solids content, and humidity and temperature measurement solutions help paper chemical companies, kraft chemical and semi-mechanical pulp mills, and paper and wood mills achieve high efficiency and essential properties in pulp, paper, paperboard, wood and timber products. Explore our full offering and applications.


Product resources

Divert Control System

Vaisala K-PATENTS® Digital Divert Control System DD-23

for black liquor and green liquor dry solids content and density measurements and recovery boiler safety in the kraft chemical (sulfate) and chemi-mechanical pulp production processes. 

Product page

Support material of the previous generations

Manuals, safety instructions, and videos for PR-23-SD SAFE-DRIVE Generation 1, Generation 2, and Generation 2.1.

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