ASTM D4178-82(2005)
(Practice)Standard Practice for Calibrating Moisture Analyzers
Standard Practice for Calibrating Moisture Analyzers
SIGNIFICANCE AND USE
This practice is intended to provide a method to calibrate moisture analyzers used on-stream or in the laboratory.
SCOPE
1.1 This practice covers a calibration technique based on the preparation of standards of known water content. This technique is applicable to the production of standards between 20 and 2000 cm3/m 3 water.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D4178–82 (Reapproved 2005)
Standard Practice for
Calibrating Moisture Analyzers
This standard is issued under the fixed designation D4178; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Significance and Use
1.1 Thispracticecoversacalibrationtechniquebasedonthe 3.1 This practice is intended to provide a method to cali-
preparation of standards of known water content. This tech- brate moisture analyzers used on-stream or in the laboratory.
nique is applicable to the production of standards between 20
3 3 4. Apparatus
and 2000 cm /m water.
1.2 The values stated in SI units are to be regarded as 4.1 Ice Bath Primary Standard Moisture Apparatus—Fig. 1
illustrates a typical system.
standard. The values given in parentheses are for information
only. 4.2 Wet Test Meter, 1-L divisions.
4.3 Bubble Meter, graduated in cubic centimetres.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 4.4 Pressure Gauge—A Bourdon-type spring gauge of test
gauge quality, 100 to 250 mm in diameter, with a scale range
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- from 0 to 400 kPa (0 to 60 psi), maximum intermediate
graduations of 1.5 kPa (0.25 psi).
bility of regulatory limitations prior to use.
4.5 Wet Mole Sieve 5A, 60/80 mesh (other mesh sizes may
2. Summary of Practice
be used, except powder).
2.1 The practice is based on the principle that ice has a
5. Preparation of Apparatus
vapor pressure of 0.611 kPa at 0°C. Therefore, when a carrier
5.1 Saturate mole sieve with water.
gas at a constant gauge pressure of 207 kPa (30 psig) is passed
throughamolecularsievesaturatedwithwaterandheldat0°C, 5.1.1 Coverinbeakerenoughmolesievetofillthewetmole
sieve container. Add water to cover mole sieve. Let stand
the total pressure is equal to 207 kPa plus 98 kPa (one
atmosphere) and the water concentration of the gas leaving the overnight.
molecular sieve is [0.611/(207 + 98)] 3 10 ppm or 2000 ppm 5.1.2 Drain the excess water by pouring the mole sieve
slurry into a filtering funnel and letting all the free water drain
volume water, regardless of flow.
2.1.1 A carrier gas at a constant gauge pressure of 207 kPa out.
is passed through a molecular sieve drier and then routed over
NOTE 1—The useful lifetime of the wet mole sieve is not known. It is
a molecular sieve support saturated with water and equilibrated
recommended that the procedure described in 5.1.1 and 5.1.2 be followed
at 0°C.
prior to each calibration.
2.1.2 By blending different volumes of the wet carrier gas
6. Procedure
with dried carrier gas, gas standards of known water concen-
tration can be prepared.
6.1 Fill the ice bath bucket for the primary standard appa-
2.2 The moisture analyzer to be calibrated is then connected ratus one third full of water; then add ice to bring the level to
to the source of the gas standard of known water concentration.
full.
6.2 Close the wet flow and the diluent flow needle values.
6.3 Turn on the carrier gas supply (nitrogen or air) and
This practice is under the jurisdiction of ASTM Committee D02 on Petroleum adjust the regulator to 207 kPa (30 psig).
ProductsandLubricantsandisthedirectresponsibilityofSubcommitteeD02.D0on
6.4 Open the diluent flow needle valve to obtain a carrier
Hydrocarbons for Chemical and Special Uses.
gas flow of 1 L/min, as measured with a wet test meter.
Current edition approved Nov. 1, 2005. Published November 2005. Originally
6.5 Allow the apparatus to equilibrate for 1 h. This allows
approved in 1982. Last previous edition approved in 1999 as D4178 – 82 (1999).
DOI: 10.1520/D4178-82R05.
the wet mole sieve to equilibrate at 0°C.
For a more complete discussion of this procedure, see Mator, R. T., “Trace
6.6 After 1 h, attach the moistu
...
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