ASTM D4052 for density, relative density and API gravity of liquids
ASTM D4052 standard test method for density, relative density, and API gravity of liquids by digital density meter
6. Apparatus
6.1 Digital Density Analyzer - A digital analyzer consisting of a U-shaped, oscillating sample tube and a system for electronic excitation, frequency counting, and display. The analyzer shall accommodate the accurate measurement of the sample temperature during measurement or shall control the sample temperature as described in 6.2. The instrument shall be capable of meeting the precision requirements described in this test method.
6.2 Circulating Constant-Temperature Bath, (optional), capable of maintaining the temperature of the circulating liquid constant to more or less 0.05℃ in the desired range. Temperature control can be maintained as part of the density analyzer instrument package.
6.3 Syringes, for use primarily in manual injections, at least 2 mL in volume with a tip or an adapter tip that will fit the opening of the oscillating tube.
6.4 Flow-Through or Pressure Adapter, for use as an alternative means of introducing the sample into the density analyzer either by a pump, by pressure, or by vacuum.
NOTE 1 - It is highly recommended that a vacuum not be applied to samples prone to light-end loss, as it can easily lead to the formation of bubbles. It is recommended to fabricate a special cap or stopper for sample containers so that air, such as from a squeeze pump, is used to displace a test specimen to the U-tube measuring cell by the flow-through method.
6.5 Autosampler, required for use in automated injection analyses. The autosampler shall be designed to ensure the integrity of the test specimen prior to and during the analysis and be equipped to transfer a representative portion of test specimen to the digital density analyzer.
6.6 Temperature Sensing Device (TSD), capable of monitoring the observed test temperature to within an accuracy of more or less 0.05℃. If a liquid-in-glass thermometer is used as the TSD, it shall be calibrated and graduated to 0.1℃, and have a holder that can be attached to the instrument for setting and observing the test temperature. In calibrating the thermometer, the ice point and bore connections should be estimated to the nearest 0.05℃. For non-mercurial thermometers, the TSD device shall be calibrated at least annually against a certified and traceable standard.
6.7 Ultrasonic Bath, Unheated, (optional), of suitable dimensions to hold container(s) placed inside of bath, for use in effectively dissipating and removing air or gas bubbles that may be entrained in viscous sample types prior to analysis.
7. Reagents and Materials
7.1 Purity of Reagents - Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination.
7.2 Purity of Water - Unless otherwise indicated, references to water shall be understood to mean reagent water as defined by Type II of Specification D1193.
7.3 Water, redistilled, freshly boiled and cooled reagent water for use as a primary calibration standard.
7.4 Cleaning Solvent, such as petroleum naphtha (Warning - Petroleum naphtha is extremely flammable), or other materials that are capable of flushing and removing samples entirely from the sample tube.
7.5 Acetone, for flushing and drying the sample tube. (Warning - Extremely flammable.)
7.6 Dry Air, for drying the oscillator tube.
