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  • PORTABLE REFRACTOMETER – J27
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Refractometer J357

Automatic Refractometer, J357 Offers Highest Performance for Research Labs.

The Rudolph J357 Automatic Refractometer, designed as a research quality instrument offers one of the highest measurement ranges of any instrument in the Rudolph refractometer product line. This instrument offers the same extra wide refractive index measurement range as our chemical industry refractometer models combined with the high accuracy of our food industry refractometer models. It also offers very powerful automatic electronic temperature control (heating and cooling) and is able to make RI and BRIX measurements at up to 100 °C.

Rudolph Research J357 Automatic Refractometer Video

The J357 is a perfect choice for the most demanding pharmaceutical, chemical, petroleum, essential oils, fragrance and cosmetic refractometer users.


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Simple Automatic Refractometer Operation

Operating the J357 Automatic refractometer is as simple as placing a sample on the artificial sapphire prism, closing the presser and reading the answer on the Digital Display — all in just a few seconds. There are no shadow lines to match and there is no eyepiece requiring any kind of operator determination or manual adjustment. When the “measure when stable mode” is selected, the J357 Refractometer automatically waits until the sample has been heated or cooled to a predefined temperature before initiating a measurement.

Automatic Refractometer – Interface Solutions

Rudolph allows the lab manager to select from different interface options because we understand laboratories and manufacturing floors have different needs when it comes to the information required for monitoring a process. Your instrument’s interface can be customized to meet the information your application and environment demand whether you choose our full featured interface or our Load-and-Go interface. The J357 offers laboratory flexibility with industrial strength and simplicity making this model series at home on the laboratory bench or on the factory floor.

Full Display with Smart Measure

Automatic Refractometer Display

Automatic Refractometer – Load – and – Go Display

Automatic Refractometer Load and Go Screen

Automatic Refractometer Trend Analysis Display

 Refractometer Trend Analysis Screen

Trend Analysis – On-Board Data Collection and Specification Range Monitoring

In a modern factory the most precious commodity is time. When a process starts to move outside its limits people want to know FAST. In other words, they want to correct the problem, preferably while it’s still small and before a product goes out of specification. The Rudolph live reading and trend analysis feature allows users to easily and quickly see how a process is going and catch minor deviations before they become major ones.

Even in the most tightly controlled manufacturing environments things do occasionally go out of specification. When out of specification conditions happen, material has to be quickly identified. Decisions have to be made as to what to do with the product. Long term data collection is a part of any good process. Knowing when and where the out of specification condition happened is equally as important. Rudolph Trend Analysis™ software quickly shows a supervisor the process history and where the problem occurred.

Dual Electronic Temperature Control to 100 °C

Unlike other temperature controlled refractometers, the J357 has temperature control from both above and below the sample. The sample cover is controlled to the same temperature as the prism. When lowered, is designed to provide a temperature controlled micro environment. It provides unrivaled temperature stability, fast measurement time and minimal evaporation. With the Auto Measure option, the sample cover can also be used to initiate measurement.

Optional Sample Presser

The Rudolph J357 is available with an optional Temperature Controlled Sample Presser that touches the sample. Compared with the standard temperature controlled cover, the optional presser reduces the empty volume of the measurement area. Therefore decreasing evaporation and at the same time helping to evenly spread semi solid materials over the measurement prism. This feature offers improved performance on many samples.

More about Rudolph Refractometer Sample Cover Options

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Automatic Refractometer Calibration

The J357 offers 1 point, 2 point or a full multi-point calibration. Calibration can be done at 20°C, 25°C or any user selectable temperature within the available range. However, regardless of how many times the refractometer has been calibrated, it can always be restored to the initial factory calibration.

On-Board Custom Scales

The J357 Refractometer is available with 100 possible programmable scales. Custom scales can be set up in a few minutes. Simply enter 2, 6 or 10 data points of concentration and corresponding RI (refractive index) value, press Compute and the instrument creates a new custom scale.

High Durability Sapphire Prism

All Rudolph J series refractometers offer a sapphire prism for high mechanical and chemical durability. The sample well is acid resistant 316 stainless steel with a Techtron sealing ring. There is no lamp to change, the LED light source is guaranteed for 1,000,000 measurements.

An Automatic Refractometer that is Easy to Clean

Automatic Refractometers - Easy to clean
No matter how good an automatic refractometer is, accurate results will only be obtained if the instrument is clean. The Rudolph J Series refractometers offer a flat, easy to clean prism that makes this process simple even with sticky samples like sugars, syrups, and petrochemicals.

User Interface

A large 7.5cm x 10cm cold cathode florescent back lit graphics, digital LCD allows the scale, sample temperature, set temperature, air temperature, time, date and temperature correction status to be easily viewed. All functions are activated through a touchscreen panel. The touchscreen will not wear out or be misplaced like traditional or detachable keypads. The digital touchscreen is resistant to fingernails, sharp objects, chemicals, and acids.

No Water Bath Needed

Automatic Refractometers Prism
Having Rudolph’s J357 fully automatic electronic temperature control means:

  • A significant savings of bench space is gained because the water bath is eliminated.
  • Integrated temperature control, the instrument knows when to measure and records both the Refractive Index measurement and the temperature.
  • Hot liquid from a bath can present a significant danger in the laboratory. In the event of a split hose, the J357 doesn’t use liquid and thereby eliminates this risk.
  • Eliminating the water bath removes the most maintenance intensive part of a Refractometer. Water baths need to be regularly filled, dosed with algaecide and cleaned.

Traceability & 21 CFR Part 11 Compliance

  • All measurements are made automatically, which eliminates the need for operator judgment.
  • Calibration with fluids traceable to NIST and calibration data securely stored and available for review.
  • Temperature can be calibrated against a traceable thermometer.
  • Operator Traceability, full 21 CFR Part 11 compliant password system.
  • Verification step with electronic signature.

Networking, Data Recording, and Data Management

The J357 offers several options for data storage. Data may be stored internally by means of an 8 MB Internal Compact Flash Memory, to a network via RS232, Cat 5 Network port, or via 3 rear and 1 side USB Ports. Storage options include writing and storing to a network, sharing to a LIMS system, and Storage to a removable USB drive.  For all data storage options see: Refractometer Data Storage
Rear Panel

A Automatic Refractometer Suitable for a Wide Range of High Demand Environments

  • Petroleum and Petrochemical Laboratories where the J357’s ability to measure at up to 100ºC without a water bath makes the instrument ideal for ASTM D1218, D2140, D1747, and D5006.
  • Research Laboratories where the wide range and high accuracy of the Rudolph J357 means researchers have the maximum chance of measuring newly synthesized products.
  • Central Research and Reference Laboratories where having the most accurate results available for setting standards for an organization or a country is needed.
  • Chemical Laboratories can measure more viscous products with a level of accuracy previously available only in narrow range food instruments.

Return to view the entire Rudolph Research Product Line

Adding Automation can Increase Throughput:

  • Testing Urine SG
  • Quality Control Automation System
  • Automated QC System
  • Maple Syrup Testing
  • Automated Color Measurement

Automatic Refractometer 20yearbanner

All Rudolph Instruments carry our exclusive 20 Commitment to service your instrument.

Rudolph Research Analytical offers a comprehensive range of Preventive Maintenance and Service Programs. Rudolph has demonstrated a commitment to its customers by keeping installed instruments operational, not only for 20 years, but in some cases for over 40 years. This long-term commitment to keeping our instruments running makes the cost of ownership, over the life of a Rudolph Instrument, one of the lowest in the laboratory market segment. At the date this document was published, there is no other laboratory instrument manufacturer guaranteeing service and technical support for 20 years. View the entire 20 Service Guarantee. 

Adding automation to this instrument will allow you to make multiple measurements at the same time, making this a robust Quality Control Automation System.
You only need one or more instruments to add either a carousel or drawer configuration to your Automated QC System

J357 AUTOMATIC Specifications
Measurement Scales Refractive Index (RI) BRIX (% sucrose) 100 User Programmable Scales
Measurement Range RI 1.26 - 1.72 , BRIX 0 - 100%, Urine SG 1.0000-1.0400
Resolution RI 0.00001 BRIX 0.001
Reproducibility RI ±0.00002, BRIX ±0.015
Accuracy RI ±0.00002, BRIX ±0.015
Optical Wavelength 589.3nm
Prism Synthetic Sapphire
Light Source Light Emitting Diode (est. life: >100,000 hrs.)
Response Time User configurable -- can be less than 2 seconds
Communication Interface 3 USB RS232 ports Cat5 Network (Ethernet)
Analog Control 0-10 volts, 4-20 mA
Temp. Control Range (Within 10C of ambient) 10ºC - 100ºC *other temperature control options are available - 5ºC – 110ºC available with temperature boost option.
Temp. Sensor Accuracy ±0.05ºC
Ambient Temp. Limit 5ºC - 40ºC
Temp. Correction Range 4ºC - 95ºC (for pure sucrose solutions)
Temp. Measurement & Control Prism surface and presser
Calibration Using water or NIST traceable standards
Operating Dimensions L: 17.25" W: 12" H: 13" / 23 lbs.
Shipping Dimensions L: 27" W: 21" H: 17" / 30 lbs.
Power Requirements 100-240 volts, 50 Hz - 60 Hz

Refractometer Info

  • Refractometer J47
  • Refractometer J57-VT
  • Refractometer J157 PLUS
  • Refractometer J257
  • Refractometer J357
  • Refractometer J457
  • TB947 Refractometer Selection Guide
  • Register Your Handheld Instrument
  • Refractometry – Measuring Refractive Index
  • Refractometers White Papers
  • Refractometer Information Request
  • Refractometer Selection Guide
  • Refractometers Flavor Fragrance Cosmetic
  • Refractometers for Chemical Industry
  • Refractometers for Sugar Milling, Refining, Processing
  • Refractometers Petroleum
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