ASTM D4052: Relative Density (Specific Gravity) by Digital Density Meter at one temperature

ASTM D4052 Density, Relative Density and API Gravity of Liquids by Digital Density Meter. please specify temperaure

Density is the mass per unit volume of a substance. In oils it has numerous uses including:

Conversion of volume measurements to mass measurements – Many equipment manufacturers specify volume requirements for lubricants. When oil is very viscous, it may be messy and difficult to obtain an accurate volume – mass may be easier to measure. Density values provide the necessary data for volume to mass conversions.
Conversion of kinematic viscosity to dynamic viscosity.
Prediction of wear particle locations – wear debris settles more rapidly in low density oils than in high density oils. When the density of the oil is very similar to the density of the particles, the particles may remain suspended in the oil.
Determination of contamination – the density will often change when the oil becomes contaminated with water, wear debris or other substances.
Determination of the composition of binary oil mixtures – if the density of each oil is known, the mixture ratio can often be determined using density.
Two values closely related to density are relative density (specific gravity) and API gravity. Relative density is the density of the sample relative to the density of water at a given temperature. In addition to providing an indication of density, relative density helps predict the location of any free water in a system.

API gravity is a scale, measured in degrees API (º API), specially designed to measure relative densities of petroleum liquids. API gravity increases as density decreases – light crude oils generally have API gravities above 31.1º API and extra heavy crude oils generally have API gravities below 10.0º API. API gravity may be used to predict volumes and densities at temperatures other than the test temperature using published tables.

In this test, the sample is carefully loaded into a digital density analyzer which is essentially an oscillating probe in a sample cell. The sample is oscillated and measured until a constant value is obtained. This value is compared to a calibrated standard. Reported is the requested density in g/ml, relative density as a unitless number or API gravity in ºAPI.

Related tests: Petro-Lubricant Testing Laboratories offers three types of tests to determine density, relative density and API Gravity:

Consider a hydrometer test (see ASTM D1298) for oils when three decimal place accuracy is sufficient, and there is no shortage of available sample.

Consider a pycnometer test (see ASTM D1481) for solids, greases and highly viscous oils.

Consider a digital density meter test (this test) for low and medium de

Instructions:

Specify temperature