MINERAL OIL ANALYTICS

The physical properties are investigated in mineral analytics.

The area of mineral oil analytics is divided as followed in our lab:

  • Gear oil (Transmission oil)
  • Hydraulic oil
  • Engine oil (Motor oil)
  • Coolant lubricants
  • Turbine oil
  • ....

We perform the following analytical methods for mineral oil analysis in our lab:

Analytical methods

Density

ISO 3675

The density of oil or fuels like diesel can be measured according to this method. The sample has to be liquid at 15°C and the vapor pressure has to be lower than 100kPa.

Flash point

ASTM D92

Petroleum products with a flash point between 79°C and 400°C can be measured with a Cleveland flash point device. For the procedure a defined amount of sample is heated up continuously. In the predicted region of the flash point every 2°C a flame is placed over the sample. The test is accomplished when the sample ignites.

Infrarotspectrocopy

This technique is used to measure the transmission of infrared light through a sample. In general different molecule structures absorb different infrared wavelength. The resulting spectrum consists of a specific pattern for the sample. In general the IR-spectroscopy is used for “finger print” analysis e.g. to control the purity of oil batches.

Corrosion test of water mixable cooling lubricants

DIN 51360-2

This method is used to check the corrosion protection of water mixable cooling lubricants. For this purpose the cooling lubricant is mixed with gray cast iron filings and incubated for a defined time on a filter paper. Afterwards the filings and the cooling lubricant are removed and the rust dots on the filter paper are categorized.

Oil content of water mixable cooling lubricants

DIN 51368

The oil content is measured by mixing a sample of the cooling lubricant with sulfuric acid and heating it up in an oven (by this the oil is separated from the aqueous part and floats on to top). The oil content is a crucial criterion for the quality of water mixable cooling lubricants. For this reason it should be observed routinely.

Pour Point

ASTM D97; DIN ISO 3016

The oil content is measured by mixing a sample of the cooling lubricant with sulfuric acid and heating it up in an oven (by this the oil is separated from the aqueous part and floats on to top). The oil content is a crucial criterion for the quality of water mixable cooling lubricants. For this reason it should be observed routinely.

Cleanliness (gravimetric)

ISO 4405

To determine the contamination of hydraulic fluids with particles, a homogenous sample is filtered and the residue is dried afterwards in an oven. The amount of residue is stated as mg/100ml sample volume.

Cleanliness (microscopie)

ISO 4406

Particles in oil or hydraulic tubes can affect hydraulic systems and reduce the lifetime of filters or damage machine parts. To analyze the amount of impurities a defined amount of sample is filtered and the amount of particles is counted and categorized in different size classes(≥4, ≥6, ≥14 µm). The higher the amount of particles in a size-class, the higher the value of the class. Samples e.g. like oil are filtered and the residue is analyzed with a microscope. Our device is able to count 1000000 particles per sample and to categorize them. It also differentiate between, non-reflective and reflective particles as well as fibers. The result is presented in the normalsize-classes and also in the microscopically size-classes (≥2, ≥5, ≥15 µm).

Foam test

ASTM D892; ASTM D6082; ISO 6247

Lube oils which are exposed to high accelerations have to be checked for their foaming behavior because the production of foam can lead to a reduction of lubricity and consequently cause machine defects. To measure the foaming behavior a defined amount of oil is place in a special glass cylinder and air is blown through at different temperatures. The amount of produced foam is recorded.

Viscosity

ASTM D445; DIN EN ISO 3104; DIN 51562-1

The viscosity plays an importantrole in motor and hydraulic oils. It is from interest that e.g. hydraulic oils don’t change their viscosity after dynamic stress, because this can cause damages to the tubes or engines. In our lab we measure by default the dynamic and kinetic viscosity.

Dynamic viscosity: Describes the flow resistance of a fluid.
Kinetic viscosity: Describes the ratio between dynamic viscosity and the density of a fluid.

Viscosity index

ASTM D2270; ISO 2909

The viscosity index describes the temperature dependency of the kinematic viscosity for oils at 40°C and 100°C. A low value shows that the viscosity highly depends on the temperature. High values mean, that the viscosity of the oil is relatively constant over a certain range of temperature.

Water content according to Karl Fischer

ASTM D6304; DIN 51777-1; DIN 51777-2; DIN EN ISO 12937

The amount of water in a sample is determined by titration with an iodine-containing solution. There are two ways to measure the water content:

Direct method (DIN 51777-1)
All liquids like alcohols and oils which are soluble in the titration solvent can be injected directly into the titration cell.

Indirect method (DIN 51777-2)
All liquids which are insoluble in the titration solvent and have a boiling temperature higher than 200°C are placed in a heating device and heated up to 200°C. The evaporated water is transported into the measuring chamber with a dry airflow. Afterwards the measurement is the same as for the direct method.