• J357 Refractometers Suppliers


Designed as a research quality instrument the Rudolph J357 Automatic Digital Refractometer offers one of the highest measurement ranges of any instrument in the Rudolph refractometer product line. This instrument offers the same extra wide RI 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.

Product Description

Simple 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 as is often necessary with ABBE Refractometers. 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.

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.

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. They want to correct the problem, preferably while it’s still small and before a product goes out of specification.

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 and, when lowered, is designed to provide a temperature controlled micro environment that 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 thereby 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.

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. Regardless of how many times the refractometer has been calibrated, it can always be restored to the initial factory calibration if required.

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.

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 which will not wear out or be misplaced like traditional or detachable keypads. The digital touchscreen is resistant to fingernails, sharp objects, chemicals, and acids.

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.

Automatic Refractometer J357 – Specifications

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 10ºC – 100ºC
*other temperature control options are available
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

Rudolph Research J 357 Automatic Refractometer Video


There are no reviews yet.

Only logged in customers who have purchased this product may leave a review.