Refractometers – Automatic, Digital J57AB & J157AB designed for the Petroleum Industry.

The J57AB and J157AB are the Petroleum specific Refractometers in the Rudolph Research Refractometer Product Line. The Rudolph Research J57AB and J157AM refractometers have temperature control and WU measurement features needed for testing required in the petroleum industry.


Designed specifically for the petroleum industry and specifically for measurement of urea, (WU) in diesel engine fuel additives, in accordance with DIN 70071 and ISO 22241-2.

Basic Operation

The J57AB is a sub-model of the fully automatic, bench-top, digital J57HA and most details on Technical Bulletin 915 apply. The J157AB is a sub-model of the J157 and most details on Technical Bulletin 911 apply. All Rudolph Research electronic refractometers feature an easy to clean, shallow sample well, fast measurement, rugged construction, and easy to read digital screens. The differences between the AB models and the standard models are as follows:

A Refractometer with Enhanced Temperature Performance

Both instruments have enhanced temperature performance to better than 0.02° C, meeting the requirements of DIN 70071 and ISO 22241-2 to ultimately deliver more accurate and consistent WU Number measurements.

On-Board R/I to WU Scale

The Rudolph J57AB refractometer is ideal for the petrochemical and petroleum industries working with diesel fuels as it displays results in refractive index (RI) which the operator may then use to automatically calculate, display, and print the WU number from the internal scale system. The Rudolph J157AB has the WU calculations built-in automatically calculating results.

Optional Refractometer Accessories

The Rudolph Research J Series AB refractometers can be supplied with the same range of accessories as the standard J Series, including:

  • Printers
  • Computer Software
  • SD card drive
  • Barcode reader
  • Automatic sipping system
  • Autosampler

Return to view the entire Rudolph Research Refractometer Product Line


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. 


Refractometers J57AB/J157AB – Specifications