Product Details

Rudolph J457 Refractometer (RRA-J457)

Rudolph J457 Refractometer


Refractometer, Rudolph’s J457 with Smart Measure™ Technology Improves Results!
All 3 models of the J457 Electronic, Digital, Refractometers come with Smart Measure™ Technology that virtually insures accurate Refractive Index (RI) and BRIX, measurements by automatically detecting when the prism is improperly cleaned, insufficient sample is loaded, or if the instrument is improperly calibrated. Various configurations are available for a small footprint, wall mount, or a remote-read factory configuration. All models come with a digital touch screen, and our Dual Temperature Control System utilizing Peltier Technology.

Delivery time: 4-6 Weeks
Delivery times may vary
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The J457 Electronic Refractometer with Smart Measure™ Advantage

Experience has shown that incorrect refractometer measurements are often linked to cross contamination caused by the previous sample being inadvertently mixed with the current sample being measured. Ensuring that the prism surface is properly cleaned between measurements can be difficult for busy environments where multiple operators are involved. Rudolph Research Analytical has solved this problem as well as the related problems an inaccurate measurement can cause.

Smart Measure™ solution:

Automated clean prism monitoring is now integrated in all Rudolph Research J457 Automatic Electronic Refractometers.
Smart Measure™ knows when the Refractometer’s prism is clean. If the prism surface does not produce the correct “Clean Prism” result then Smart Measure™ notifies the operator that further cleaning of the prism is necessary. Smart Measure™ notifies the operator that it is ready to measure after the prism is satisfactorily cleaned. The refractometer is now ready to make an accurate RI or BRIX reading with a verified clean sample well.

A small drop of sample in the center of the prism will measure correctly. A large drop of sample completely covering the prism surface will measure correctly. A small drop on the perimeter of the prism will produce erroneous RI and BRIX readings with the reason often unknown to the operator.

Smart Measure™ solution:

Automated sample load monitoring – reduces refractometer user error.
Smart Measure™ knows when a sample has been loaded on the refractometer‘s prism and immediately begins evaluating various metrics surrounding the sample load. If Smart Measure™ determines that those metrics indicate proper sample loading, it will display the result with a sample quality number. If Smart Measure™ determines that the metrics indicate an improper sample load, Smart Measure™ will ask the operator to clean the prism and re-load the sample.

Measurement problem:

> Sample contamination or improper refractometer calibration

An improperly cleaned refractometer prism, where sample residue is left in the measurement well, can mix with a water zero or calibration fluid. This type of contamination during the refractometer calibration process will cause an error across all subsequent measurements, yielding incorrect RI and BRIX readings.

Smart Measure™ solution:

Automated sample calibration inspection
Smart Measure™ is constantly measuring the refractometer’s prism surface and monitoring the value measured against its database of results. If during a water zero calibration the instrument detects a value that is too different from the database or the RI value being input is far from the measured value, it will alert the operator.

Measurement problem:

> The sample has air bubbles that affect measurement results

Many samples have air trapped inside them or are carbonated. These samples read well most of the time as long as air bubbles are not trapped between the refractometer’s prism surface and the sample. When this happens the operator gets an erroneous result often referred to as a flyer. These results are called flyers because the measured value is quite different from the expected measurement value.

Smart Measure™ solution:

Automated sample calibration inspection
Smart Measure™ catches these flyers by scanning the detector for varying RI values and then alerts the user to reload the sample. Since the user does not get a value to record until a new sample load is completed, Smart Measure™ greatly reduces the erroneous refractometer measurements from being recorded.

Smart Measure™ Features

Smart Measure™ knows when to measure and display a result even when the operator does not.

Smart Measure™ Features – J457 Electronic Refractometers (all models)
Dirty prism detection
Incorrect calibration detection
Insufficient sample load detection
Cross contamination detection
Improper water zero detection
Trapped air bubble on prism surface detection

Rudolph’s exclusive Electronic Dual Temperature Control System
All J457 models come with Rudolph’s exclusive Dual Temperature Control System utilizing Peltier Technology. The J457 Refractometer heats and cools the sample from both prism surface and sample cover. The insulating cover housing seals the Prism Well Ring to create a uniform temperature environment providing unmatched temperature control uniformity resulting in consistently accurate RI measurements.

The Rudolph Research J457 line of Automatic Refractometers, come in three configurations to match your operating conditions and industry requirements.

J457-SC Automatic Refractometer in Standard Bench-top Configuration

J457-SC Refractometer in the Standard Configuration is Rudolph’s most popular configuration and provides an excellent combination of a small footprint and a large, easy-to-navigate digital touch screen interface.

J457-WC Automatic Refractometer in a Wall Mount Configuration

J457-WC Refractometer in a compact Wall Mount Configuration is designed for production environments where water is used for cleaning or there is a lot of sample spillage on the work surface. This configuration is also excellent for situations where there is very little work space available: out on the factory floor or in an over crowded satellite laboratory where there is little to no remaining bench space for a standard Bench-top configuration.

J457-FC Automatic Refractometer in Factory Configuration

J457-FC Refractometer in Factory Configuration is recommended when there is a lot of sample spillage on the laboratory’s instrumentation. Factories working with sticky resins and syrups that end up being spilled on the instrumentation are great candidates for the J457-FC as the measurement unit can be as much as six feet away from the display unit.

J457 Automatic Refractometer Specifications (all models)

Measurement Scales

Refractive Index (nD)
BRIX (% sucrose)
and up to 100 custom programmed scales

Measurement Range

Refractive Index 1.26 – 1.72,
BRIX 0 – 100


Refractive Index ±0.00002,
BRIX ±0.01


Refractive Index ±0.00002,
BRIX ±0.01


Refractive Index 0.00002
BRIX 0.01

Temp. Control Range

10°C to 110°C (wider temperature range available dependent on ambient conditions and options).
Temperature controlled by dual Peltier system; boost option to 120°C available

Temp. Control Reproducibility


Ambient Temp. Limit

5°C to 40°C

Temp. Correction Range

4°C to 95°C (for sucrose solutions)

Sample Temp. Limit

-20°C to 250°C

Optical Wavelength

589.3nm (NaD line)

Response Time

User configurable, generally less than 30 seconds


Using water or NIST traceable fluids. Factory default calibration can always be reset


Artificial Sapphire

Acid Resistance

Hastelloy™ measurement surface (optional)

Data Storage/Internal Memory

8GB non-removable Compact Flash


10.4 inch diagonal, 800×600 pixels, color, Flat Panel Monitor with Resistant Touch Screen Interface, 400 nits brightness, gasketted for spill protection.

User Interface


Communication Interface

3 USB, RS232 and Cat5 Network (Ethernet)

Operating Dimensions/Weight

L: 17 ¼”, W: 12”, H: 13” / 23 lbs.
L: 43.5 cm, 30.5 cm, 33 cm / 10.4 kg

Power Requirements

100 – 240 volts, 50 Hz – 60 Hz


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