|AVIATION - COMMON USES OF REFRACTOMETERS IN AVIATION AND ASSOCIATED INDUSTRIES
There are a number of applications where hand or even process refractometers may be used in the aviation
In extreme conditions, moisture on aircraft wings can create extra weight and unwanted drag during
take-off. Prior to take-off, aircraft are sprayed with a special type of antifreeze that adheres
to the aircraft surfaces and prevents freezing. The antifreeze is supplied to the airport as a
concentrate, which is then diluted on site. A hand held refractometer is used to check the dilution
ratio. Typical scales include Refractive Index (RI) and °Brix, with a chart being used to
ascertain the correct value (e.g. Kilfrost ABC).
Fuel System Icing Inhibitor (ASTM D 5006)
Additives are also present in aviation fuel and a refractometer is a common method used to check this
parameter. Some special instruments are available with Diethylene Glycol Monomethyl Ether (DiEGME)
& Ethylene Glycol Monomethyl Ether (EGME) scales but most commonly used is the °Brix refractometer
with a correction factor as shown in the relevant American Society for Testing and Materials (ASTM)
In some instances, the special scales have been loaded to a digital refractometer offering much higher
Refractometers are often used as a quality check to determine the concentration of liquid fire fighting
foams. Both refractive index and °Brix scales are used, with reference to a dilution chart
supplied by the foam manufacturer.
Coolants for Machine Shops
Extruded metal & machined parts rely on coolants made of mineral or synthetic oils mixed with water
(emulsions). In order to prevent damage to the part being manufactured or the tool being used, it
is essential to control the ratio of oil to water. This is done by way of a refractometer and
conversion chart. Commonly hand held refractometers are used but for some larger operations,
continuous monitoring and automatic blending is carried out by a process system.
For more information on hand held refractometers which can provide measurements for anitfreeze, coolant,
fuel addative, and foam applications please see the E-line optical refractometer,
OPTi digital refractometer, and
Eclipse hand held refractometer web pages.
Every effort has been made to ensure the accuracy of the contents of this FAQ. However, Xylem Inc.
can assume no responsibility for errors contained in this FAQ.