K27500 Automatic Petroleum Refractometer


Test Method
Refractive index is a fundamental physical property that is used in conjunction with other properties to characterize pure hydrocarbons and their mixtures. It is a useful property for concentration measure-ments, purity determinations and chemical identification.

Features and Benefits

• Conforms to ASTM D1218 and D1747 test specifications

• Electronic heating and cooling Peltier system eliminates the need for a circulating water bath

• Automated and precise refractive index measurements

• Rugged sapphire prism

• Designed for samples ranging from clear to highly colored, dark and opaque

• Measures to the fifth decimal place refractive index or hundredths place in percent solids

• Clear graphical LCD display with on-screen instructions and
full menu operation

• Multipoint calibration routines maximize accuracy

• Countdown timer insures consistent sample equilibration times

• RS232C communication ports


K27500 Automatic Petroleum Refractometer
The Koehler Automatic Refractometer uses precision optics and superior image analysis to extend the repeatability and accuracy of refractive index measurements for petroleum products. Subjectivity is removed from tests results because no manual activities such as aligning shadowlines or reading analog scales are necessary. Opaque hydrocarbons present no problem for this unit which uses reflected light measurement technology as opposed to manual refractometers which are of the transmission type.

The refractometer incorporates numerous innovations designed to improve the accuracy of petroleum product testing. A 2600 cell linear scanned diode array shadowline sensor is sensitive enough to read even the most demanding samples. A 589 nanometer filter gives true Sodium D-Line refractive index readings. The large graphical LCD is easy to read and provides complete sample analysis documentation including the reading, temperature and scale name of the screen. Documentation is also output through two RS232C serial ports for export to either a PC or a printer. Optional Refractometer Communication Software package provides real-time output directly into Microsoft® Excel.

Set-up, diagnostic and calibration routines are displayed with easy to follow step-by-step instructions. User-developed customer calibration curves may be programmed allowing automatic temperature correction and direct percent concentration, percent reaction completion, etc. This unit has been used successfully throughout the petrochemical industry.

Measurement Scales:
Refractive Index (RI)
BRIX (% sucrose)
Temperature Corrected RI
Temperature Corrected BRIX
Ten User-Programmable Scales

Illumination: 589nm light emitting diode with interference filter (estimated life: 100,000 hrs)

Dissolved Solids: 0 to 95% solids
Refractive Index: 1.32000 to 1.70000nD
(nD - Sodium D-Line Refractive Index)

Standard Mode: 0.1% Solids 0.0001nD
Extended Mode: 0.01% Solids 0.00001nD

Standard Mode: ±0.1% Solids ± 0.0001nD
Extended Display Mode: Refractive Index Standard Oils ± 0.00002
Typical clear aqueous samples, % Solids Temperature Compensated, as sucrose ±0.02%

Calibration Fluid: refractive index standard oil, NIST traceable
nominal value 1.495 RI, 67.61 BRIX

Sample Types: Transparent, translucent or opaque

Sample Temperature Control: Peltier heat (cool) exchanger surrounding prism permits temperature control from 10 to 70°C without an external water bath circulator

Prism Assembly: Stainless steel, synthetic sapphire sealed with solvent-resistant epoxy

1 point - Water only
2 point - Water and refractive index or Brix standard

Dimensions lxwxh,in.(cm)
15.5x10x4.5 (39.5x25.5x11.5)
Net Weight: 23 lbs (10.5kg)

Shipping Information
Shipping Weight: 30 lbs (14kg)
Dimensions: 5 Cu. ft.

Ordering Information



Product Description

Electrical Requirements


Automatic Petroleum Refractometer

115V 50/60Hz


Automatic Petroleum Refractometer

230V 50/60Hz




Product Description


Calibration Fluid
Certificate of NIST traceability included.


Refractometer Communication Software Package with real-time data export into Microsoft® Excel.