ASTM D664- Acid Number of Petroleum Products by Potentiometric Titrations

The Total Acid Number (TAN) result is expressed as the volume (mg) of potassium hydroxide (KOH) required to neutralize all the acidic components in one gram of sample. The reported unit of measure is mgKOH/g of oil. Some anti-rust and anti-wear additives can cause the oil to have a high TAN value. As the oil ages theses additives can slightly decrease or deplete. As the oil oxidizes, small amounts of by-products are formed in the oil causing the TAN to increase.

ASTM D2896- Test Method for Base Number of Petroleum Products by Potentiometric Perchloric Acid Titration

This quantitative test method determines inorganic and organic basic constituents. The reported unit of measure is mgKOH/g of oil. The reserve alkalinity is sometimes used as a measure of additive depletion.

ASTM D4739-Test Method for Base Number Determination by Potentiometric Titration

This quantitative test method determines inorganic and organic basic constituents. The titrant used in this method in Hydrochloric acid. This titration is a slower titration than the ASTM D2896 method. The reported unit of measure is mgKOH/g. The reserve alkalinity is sometimes used as a measure of additive depletion.

ASTM D2893- Test Method for Low Temperature Viscosity of Lubricants Measured by Brookfield Viscometer

Apparent viscosity is determined by a Brookfield Viscometer. A Brookfield Viscometer measures the torque required to rotate a spindle at constant speed in oil at a specified temperature. The temperature can range from -5C to -40C. This method is used for measuring low temperature viscosity of lubricants.

ASTM D92- Test Method for Flash and Fire Points by Cleveland Open Cup

A fixed volume of fluid is heated at a uniform rate as a small flame is passed over the surface. The point at which the vapors ignite is called the flash point.

ASTM D892- Test Method for Foaming Characteristics of Lubricating Oils

This method determines the foaming characteristics of lubricating oils at 24C & 93.5C. A fixed volume of oil is heated to test temperature and then aerated by flowing air at a fixed rate through a gas diffuser stone. The volume of foam after 5 minutes and then after 10 minutes of settling are recorded. Typically there are three sequences in this method. Sequence I is at the 24C test temperature and Sequence II is at the 93.5C test temperature. Sequence III is the same aliquot as Sequence II. ASTM definition of foam is a collection of bubbles formed in the liquid o on (at) its surface in which the air (or gas) is the major component on a volumetric basis.

ASTM D4052- Standard Test Method for Density and Relative Density of Liquids by Digital Density Meter

The definition of density is the mass of a unit volume of a substance. Its value varies with the units used. This test method measure density between 15 and 35C and is restricted to liquids with vapor pressures below 600mm Hg (80K Pa) and viscosities below about 15,000 cst at test temperature. A small volume of liquid is injected into an oscillating sample tube. The change in the oscillating frequency caused by the change in the mass of the tube is in combination with the calibration is used to determine the density the liquid.

The definition of relative density is the ratio of the density of a material at a stated temperature to the density of water at a stated temperature.

The definition of API gravity is a gravity scale established by the American Petroleum Institute and in general use in the petroleum industry. The unit “A.P.I degree” is the unit defined in terms of specific gravity as follows:

API Gravity= 141.5/Specific Gravity @60F/60C – 131.5

AAMFTIR- Fourier Transformed Infrared Spectroscopy

Used as a “fingerprint” to identify or compare material by measuring the amount of infrared light passed through the sample from about 4000 cm-1 to 600 cm-1 frequency. This is done by vibrational absorption occurring in the infrared region where the energy of radiation is insufficient to excite electronic transitions. Infrared spectra exhibit narrow, closely spaced absorption peaks resulting from transitions among the various vibrational quantum levels. The FTIR offers the advantages of unusually high sensitivity, resolution and speed of data acquisition.

Inductively Coupled Plasma- ICP.

This instrument is used to measure wear and additive elements.

A high temperature discharge of 10,000K is generated by flowing ionizable gas (Argon) through a magnetic field induced by a loaded coil that surrounds the carrier gas- called plasma. An aerosol sample stream is carried through the center of the plasma discharge and is dissolved, atomized and the resultant elements are then excited.  After excitation, light is emitted at their characteristics wavelengths. This light is then transmitted to the optical system of the ICP.

The optical system consist of entrance and exit slits, grating pieces and a photo multiplier tubes. The light from the atoms are focused on an entrance slit of polychromators and dispersed by diffraction grating.  A narrow range of dispersed wavelengths pass through an exit slit, which falls on to a photo multiplier tube detector. The photo multiplier tubes convert light energy to an electrical current.  The magnitude of current is proportional to light intensity. The current is then integrated over a period of time. The integrated change is measured by a detector circuit to the computer.

ASTM D5949-Test Method for Pour Point of Petroleum Products (Automatic Pressure Pulsing Method)

Pour Point is the lowest temperature at which oil is observed to flow. The pour point measurement is 3C above the temperature at which the oil shows no movement.

150 micro-liters of test sample is injected into the sample cup located in the automatic pour point apparatus.  The sample is cooled by a Peltier device.  At temperature levels of 1, 2, or 3C (depending on your selection), a controlled burst of nitrogen is applied onto the surface of the sample.  Multiple optical detectors, along with a light source, monitor the movement of the surface of the sample.  The lowest temperature of movement observed is recorded as the pour point.

ASTM D6304- Test Method for Determination of Water in Petroleum Products, Lubricating Oils, and additives by Coulometric Karl Fischer Titration

A sample is weighed into a vial and heated on an evaporation chamber. The vaporized water is then carried into the Karl Fisher titration vessel by dry air or inert gas.  Iodine for the Karl Fisher reaction is generated coulometrically at the anode.  When all of the water has been titrated, an electrometric end point detector detects excess iodine and the titration is terminated.  1 mol of iodine reacts with 1 mol of water.

ASTM D611- Test Method for Aniline Point and Mixed Aniline Point of Petroleum Products and Hydrocarbons

The oil sample is mixed with Aniline and is heated at a controlled rate until the mixture is miscible. The lowest temperature at which the mixture becomes miscible is recorded. This test measures the aromatic content of a hydrocarbon blend.

ASTM D5293- Test Method for Apparent Viscosity of Engine Oils Between -5 and -35 C Using the Cold Crank Simulator

This test method covers the laboratory determination of apparent viscosity of engine oils at temperatures between –5 and -35C and at high shear rates.  The results are related to engine cranking characteristics of engine oil. A measured amount of sample is subjected to an extreme low temperature for 3 minutes.  The rotor spins for 1 minute in the sample   and the speed of the rotor is measured by keeping ohms resistance at zero.  The speed-reading is used to determine the viscosity on a calibration curve.

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