ASTM D5931-96(2002)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D5931–96 (Reapproved 2002)
Standard Test Method for
Density and Relative Density of Engine Coolant
Concentrates and Aqueous Engine Coolants by Digital
Density Meter
This standard is issued under the fixed designation D 5931; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope caused by the change in the mass of the tube is used in
conjunction with calibration data to determine the density of
1.1 This test method covers the determination of the density
the sample.
or relative density of engine coolant concentrates and aqueous
engine coolants.
5. Significance and Use
1.2 This test method should not be applied to samples so
5.1 Density is a fundamental physical property that can be
dark in color that the absence of air bubbles in the sample cell
usedinconjunctionwithotherpropertiestocharacterizeengine
cannot be established with certainty.
coolant concentrates and aqueous engine coolants.
1.3 The accepted units of measure for density are grams per
5.2 Determination of the density or relative density of these
milliliter or kilograms per cubic meter.
products is necessary for the conversion of measured volumes
1.4 This standard does not purport to address all of the
to volumes at the standard temperature of 20°C (68°F).
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
6. Apparatus
priate safety and health practices and determine the applica-
6.1 Digital Density Analyzer, consisting of a U-shaped,
bility of regulatory limitations prior to use. For specific hazard
oscillating sample tube and a system for electronic excitation,
statements, see Note 1.
frequency counting, and display. The analyzer must accommo-
2. Referenced Documents date the accurate measurement of the sample temperature
during measurement or must control the sample temperature as
2.1 ASTM Standards:
2 described in 6.2. The instrument must meet the precision
D 1193 Specification for Reagent Water
requirements described in this test method.
D 4052 Test Method for Density and Relative Density of
3 6.2 Circulating Constant—Temperature Bath, (optional) ca-
Liquids by Digital Density Meter
pable of maintaining the temperature of the circulating liquid
3. Terminology constant to 60.05°C in the desired range. Temperature control
can be maintained as part of the density analyzer instrument
3.1 Definitions:
package.
3.1.1 relative density, n—the ratio of the density of a
6.3 Syringes, at least 2 mL in volume with a tip or an
material at a stated temperature to the density of water at the
adapter tip that will fit the opening of the oscillating tube.
same stated temperature.
6.4 Flow-Through or Pressure Adapter, for use as an
4. Summary of Test Method alternative means of introducing the sample into the density
analyzer either by a pump or by vacuum.
4.1 A small volume of liquid sample is introduced into an
6.5 Thermometer, calibrated and graduated to 0.1°C, with a
oscillatingsampletube,andthechangeinoscillatingfrequency
thermometer holder that can be attached to the instrument for
setting and observing the test temperature. In calibrating the
This test method is under the jurisdiction ofASTM Committee D15 on Engine
thermometer, the freeze point should be estimated to the
Coolants and is the direct responsibility of Subcommittee D15.03 on Physical
nearest 0.05°C.
Properties.
Current edition approved April 10, 1996. Published June 1996.
Annual Book of ASTM Standards, Vol 11.01.
Annual Book of ASTM Standards, Vol 05.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D5931
7. Reagents and Materials suitable syringe. The test portion must be homogeneous and
free of even the smallest air or gas bubbles. The sample tube
7.1 Purity of Reagents—Use reagent grade chemicals in all
does not have to be completely full as long as the liquid
tests. Unless otherwise indicated, all reagents shall conform to
meniscus is beyond the suspension point. Allow the display to
the specifications of the Committee on Analytical Reagents of
reach a steady reading and record the T-value for water.
the American Chemical Society, where such specifications are
9.2.4 Record the density of air at the temperature and
available. Other grades may be used, provided it is first
atmospheric pressure of the test. Calculate the density of air at
ascertained that the reagent is of sufficiently high purity to
the temperature of test using the following equation:
permit its use without lessening the accuracy of the determi-
nation.
d , g/mL 5 0.001293@273.15/T#@P/760# (1)
a
7.2 Purity of Water—Unless otherwise indicated, references
to water mean reagent water as defined by Type II of
where:
Specification D 1193.
T = temperature, degrees Kelvin, K, and
7.3 Water, redistilled, freshly boiled and cooled reagent
P = barometric pressure, torr.
water for use as a primary calibration standard.
9.2.5 Determine the density of water at the temperature of
7.4 Acetone, for flushing and drying the sample tube.
test by reference to Table 1.
NOTE 1—Warning: Acetone is extremely flammable.
9.2.6 Using the observed T-values and the reference values
for water and air, calculate the values of the constants A and B
7.5 Dry Air, for drying the oscillator tube.
using the following equations:
8. Preparation of Apparatus
2 2
A 5 @T 2 T #/@d 2 d # (2)
w a w a
8.1 Set up the density analyzer and constant temperature
B 5 T 2 ~A 3 d ! (3)
a a
bath following the manufacturer’s instructions.Adjust the bath
or internal temperature control so that the desired test tempera-
where:
ture is established and maintained in the sample compartment
T = observed period of oscillation for cell containing
w
of the analyzer. Calibrate the instrument at the same tempera-
water,
ture at which the density of the sample is to be measured.
T = observed period of oscillation for cell containing air,
a
d = density of water at test temperature, °C, and
w
NOTE 2—Precise setting and control of the test temperature in the
d = density of air at test temperature,° C.
a
sample tube is extremely important. An error of 1.0°C can result in a
Alternatively, use the T and d values for the other reference
change in density of one in the third decimal place.
liquid if one is used.
9. Calibration of Apparatus
9.2.7 If the instrument is equipped to calculate density from
the constants A and B and the observed T-value from the
9.1 Calibrate the instrument when first set up and whenever
sample, enter the constants in the instrument memory in
the test temperature is changed. Thereafter, conduct calibration
accordance with the manufacturer’s instructions.
checks at weekly intervals during routine operation.
9.2.8 Check the calibration and adjust if needed by perform-
9.2 Initial calibration, or calibration after a change in test
ing the routine calibration check described in 9.3.
temperature, necessitates calculation of the values of the
9.2.9 To calibrate the instrument to display relative density,
constants A and B from the periods of oscillation (T) observed
that is, the density of the sample at a given temperature relative
when the sample cell contains air and redistilled, freshly boiled
to the density of water at the same temperature, follow
and cooled reagent water.
9.2.1-9.2.7, but substitute 1.000 for d in performing the
9.2.1 While monitoring the oscillator period, (T), flush the w
calculations described in 9.2.6.
sample tube with distilled water followed by an acetone flush
9.3 Weekly calibration adjustments to constants Aand B can
and drying with dry air. Contaminated or humid air can affect
be made if required without repeating the calculation proce-
the calibration. When these conditions exist in the laboratory,
dure.
pass the air used for calibration through a suitable purification
and drying train. In addition, the inlet and outlet ports for the
A
TABLE 1 Density of Water
U-tube must be plugged during measurement of the calibration
Temper- Temper- Temper-
air to prevent ingress of moist air.
Density, Density, Density,
ature, ature, ature,
g/mL g/mL g/mL
9.2.2 Allow the dry air in the U-tube to come to thermal
°C °C °C
equilibrium with the test temperature and record the T-value
0 0.99987 21 0.99802 40 0.99224
for
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