In food, beverage, dairy and brewery applications, concentration measurement plays a critical role in product quality, process efficiency and batch consistency. Parameters such as Brix, total solids, Plato, Baume and other concentration values must be measured accurately and continuously to keep production under control.
The Vaisala Polaris PR53AC Sanitary Compact Process Refractometer is designed for inline liquid concentration measurement in hygienic process environments. With optical refractive index technology, sanitary design, 3-A and EHEDG certifications, built-in analog and digital outputs, and compatibility with Vaisala Indigo520 and Indigo80, PR53AC provides a reliable measurement solution for modern sanitary production lines.
What Is Vaisala PR53AC?
The PR53AC is a sanitary compact process refractometer designed to measure liquid concentrations directly in the process stream. It is especially suitable for food, beverage, dairy and brewery industry applications, as well as OEM systems requiring compact inline concentration measurement.
The instrument measures concentration using refractive index, also known as RI. It can be configured for Brix, Total Solids, Oechsle, Baume, Plato and more than 500 concentration curves.
This flexibility allows the same refractometer platform to be used in many different liquid concentration applications.
Reliable Optical Measurement Principle
The PR53AC uses optical measurement based on refractive index. Refractive index is a property that can be measured from practically any liquid and responds to dissolved material in the process medium.
Because the measurement is optical, it is not affected by bubbles, particles, suspended solids or liquid color. This is a major advantage in food and beverage processes, where liquids may contain fibers, particles, air bubbles or color changes during production.
The result is continuous, fast and stable concentration measurement directly from the process line.
Brix and Beyond
Brix is one of the most common measurement units in food, dairy and beverage processing. It is widely used for sugar concentration control in products such as juices, syrups, dairy products, soft drinks and brewing processes.
PR53AC can also display measurements in Total Solids, Oechsle, Baume and Plato. Other concentration units and curves are available for substances such as sucrose, gelatin, lactulose and hydrogen peroxide.
The refractometer is supplied pre-configured with the selected concentration curve, simplifying commissioning and integration into the process.
Designed for Sanitary Applications
The PR53AC is designed for hygienic process environments and is certified according to 3-A and EHEDG requirements. These certifications help ensure that hygienic demands and safety requirements are met in food, beverage and dairy applications.
The product is compatible with clean-in-place (CIP) and sterilization-in-place (SIP) systems. This is essential for sanitary production lines where equipment must be cleaned and sterilized without being removed from the process.
Sanitary Materials and Traceability
The PR53AC wetted parts are designed for direct contact with process media. Materials include AISI 316L stainless steel, modified PTFE, EPDM gaskets and sapphire monocrystalline prism.
The sensor head surface roughness is specified as Ra 0.8 µm, with Ra 0.38 µm electropolished option. These sanitary surface qualities support cleanability and hygienic operation.
The datasheet also states material compliance with FDA, EC 1935/2004, EC 2023/2006 GMP and EU 10/2011 requirements, supporting use in regulated food-contact applications.
Measurement Performance
The PR53AC has a refractive index measurement range of 1.32–1.53 nD, corresponding to 0–100 °Bx.
Accuracy is specified as ±0.00014 nD, equivalent to 0.1 °Bx. Repeatability is ±0.00002 nD, and resolution is ±0.000015 nD.
The response time is 10 seconds with default damping, and the measurement cycle is 1 measurement per second. Long-term stability is specified as a maximum of 0.1% full scale per year.
These performance values make PR53AC suitable for continuous process control and quality monitoring.
Temperature Measurement and Compensation
The PR53AC includes temperature measurement with an accuracy of ±0.3 °C at 20 °C. The sensor class is F0.15 according to IEC 60751, and the temperature coefficient is ±0.002 °C/°C.
Temperature measurement is important because concentration calculations often depend on temperature compensation. By measuring process temperature directly, the refractometer supports stable and accurate concentration output in changing process conditions.
Process Conditions
The PR53AC can operate in process temperatures from -40 °C to +150 °C, depending on gasket material. With EPDM gasket, the process temperature range is -40 °C to +130 °C. With PTFE gasket, the process temperature range is -40 °C to +150 °C.
The design temperature is +180 °C, and design pressure is 40 bar at +20 °C. The operating pressure depends on clamp rating and process temperature. The datasheet recommends a high-pressure clamp above 120 °C.
The instrument has IP66 and IP67 protection ratings and Type 4X enclosure rating, supporting industrial and washdown environments.
Outputs and Connectivity
PR53AC includes built-in analog and digital communication capabilities. Output parameters include refractive index, temperature, concentration and quality factor.
The analog output is an isolated, configurable mA output according to NAMUR NE 43, with a range of 3.8–20.5 mA and maximum load of 600 Ω. The analog output accuracy at +20 °C is ±0.1% of full scale.
Digital communication is provided through RS-485 Modbus RTU, with a maximum cable run of 300 m. The device also supports HART 7, allowing convenient integration with industrial control and diagnostic systems.
Compatibility with Indigo520 and Indigo80
The PR53AC can be interfaced directly or connected to the Vaisala Indigo520 transmitter. When connected to Indigo520, users gain access to additional features such as data storage, graphical interface and analog or digital interfaces.
The Indigo520 is required when the application or installation position requires a wash system to control the process. Settings, measurement parameters and service updates can be managed directly through Indigo520 or by using Vaisala software via USB.
The PR53AC can also be connected to the Indigo80 handheld indicator, which is useful for portable diagnostics and field service.
Wash System for Sticky Processes
Most PR53AC applications do not need a wash system because the shear force of the process flow keeps the measurement point clean. This self-cleaning effect reduces maintenance requirements in many inline installations.
For sticky or more demanding process conditions, a powerful wash system can be used to ensure correct measurement. Wash nozzle options are available with flow cell configurations, including steam wash, water wash and pressurized water wash.
Flow Cell Options
The PR53AC can be installed directly into process lines using sanitary couplings or with flow cells. Flow cells are compatible with PR53AC versions that have 2.5" sanitary process connection.
Available flow cell options include SEFC Sanitary Elbow Flow Cell, SEFCL Sanitary Elbow Flow Cell for large pipelines and MFC Miniature Flow Cell.
SEFC flow cells are available for 1", 1.5", 2" and 2.5" pipelines, while SEFCL flow cells are available for 3" and 4" pipelines. The MFC miniature flow cell is suitable for smaller flow paths such as 4 mm, 5 mm and 6 mm.
These options make PR53AC adaptable to different pipe sizes, flow rates and process layouts.
Installation and Sanitary Couplings
PR53AC supports sanitary coupling installation, including 3-A and Type N sanitary couplings. It can be installed directly into pipelines with sanitary clamps or through optional flow cells.
Sanitary mounting accessories include welding ferrules, sanitary clamps, high-pressure clamps, blind flanges and sanitary gaskets. Type N mounting accessories are also available for Type N clamp installations.
This installation flexibility makes the device suitable for both new hygienic lines and modernization projects.
Accessories and Calibration Tools
Vaisala offers calibration and verification accessories for PR53AC. These include verification kits, calibration kits, high-range special kits and sample holder accessories.
Instrument cables are available in 10 m, 30 m and 50 m lengths. A USB adapter is available for the service port and Insight service software. A cooling cover is also available as an accessory.
These accessories support commissioning, verification, service and long-term maintenance.
Why Choose PR53AC?
PR53AC is a strong choice for hygienic processes that require accurate inline concentration measurement. It combines sanitary design, reliable optical measurement, strong long-term stability and flexible integration.
Because the measurement is not affected by bubbles, particles, suspended solids or color, the device can perform reliably in many food and beverage applications where traditional measurement methods may require laboratory sampling or frequent maintenance.
Its no-moving-part design, CIP/SIP compatibility, 3-A and EHEDG certification, Indigo520 integration and flow cell options make it especially suitable for hygienic production environments.
Conclusion
The Vaisala Polaris PR53AC Sanitary Compact Process Refractometer provides reliable inline concentration measurement for hygienic process applications. With refractive index technology, 3-A and EHEDG certification, Brix and over 500 concentration curve options, built-in 4–20 mA, HART and Modbus RTU outputs, and compatibility with Indigo520 and Indigo80, it offers a powerful measurement solution for food, beverage, dairy and brewery industries.
For producers who need continuous Brix, total solids or liquid concentration measurement directly in the process stream, PR53AC delivers accurate, stable and sanitary performance with low maintenance requirements.