ASTM D2112-01a(2007)
(Test Method)Standard Test Method for Oxidation Stability of Inhibited Mineral Insulating Oil by Pressure Vessel
Standard Test Method for Oxidation Stability of Inhibited Mineral Insulating Oil by Pressure Vessel
SCOPE
1.1 This test method covers and is intended as a rapid method for the evaluation of the oxidation stability of new mineral insulating oils containing a synthetic oxidation inhibitor. This test is considered of value in checking the oxidation stability of new mineral insulating oils containing 2,6-ditertiary-butyl para-cresol or 2,6-ditertiary-butyl phenol, or both, in order to control the continuity of this property from shipment to shipment. The applicability of this procedure for use with inhibited mineral insulating oils of more than 12 cSt at 40°C (approximately 65 SUS at 100F) has not been established.
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. (See warning in 6.7.)Note 1
A modification of this test method, which uses the same procedure and apparatus but a higher (150°C) bath temperature, has been published as Test Method D 2272.
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Designation: D2112 − 01a(Reapproved 2007)
Standard Test Method for
Oxidation Stability of Inhibited Mineral Insulating Oil by
Pressure Vessel
This standard is issued under the fixed designation D2112; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope oxygen pressure of 90 psi (620 kPa), in a stainless steel or
copper vessel (for rapid temperature equilibrium), with a glass
1.1 This test method covers and is intended as a rapid
test specimen container and copper catalyst coil, in the pres-
method for the evaluation of the oxidation stability of new
ence of water, at a bath temperature of 140°C. The time for an
mineral insulating oils containing a synthetic oxidation inhibi-
oil to react with a given volume of oxygen is measured;
tor. This test is considered of value in checking the oxidation
completion of the test is indicated by a specific drop in
stability of new mineral insulating oils containing 2,6-
pressure.
ditertiary-butyl para-cresol or 2,6-ditertiary-butyl phenol, or
both, in order to control the continuity of this property from
4. Signifance and Use
shipment to shipment. The applicability of this procedure for
4.1 This is a control test of oxidation stability of new,
use with inhibited mineral insulating oils of more than 12 cSt
inhibited mineral insulating oils for determining the induction
at 40°C (approximately 65 SUS at 100°F) has not been
period of oxidation inhibitors under prescribed accelerated
established.
aging conditions. There is no proven correlation between oil
1.2 This standard does not purport to address all of the
performance in this test and performance in service. However,
safety concerns, if any, associated with its use. It is the
the test method may be used to check the continuity of
responsibility of the user of this standard to establish appro-
oxidation stability of production oils.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. (See warning in
5. Apparatus
6.7.)
5.1 Oxidation Vessel— Glass test specimen container with
NOTE 1—A modification of this test method, which uses the same
cover and catalyst coil, pressure gage, thermometer, test bath,
procedure and apparatus but a higher (150°C) bath temperature, has been
and accessories as described in Annex A1. The assembled
published as Test Method D2272.
apparatus is shown in Fig. 1, and its design shown schemati-
cally in Fig. 2.
2. Referenced Documents
2.1 ASTM Standards:
6. Reagents and Materials
B1 Specification for Hard-Drawn Copper Wire
6.1 Purity of Reagents—Use reagent grade chemicals in all
D2272 Test Method for Oxidation Stability of Steam Tur-
tests. Unless otherwise indicated, all reagents shall conform to
bine Oils by Rotating Pressure Vessel
the specifications of the Committee on Analytical Reagents of
E1 Specification for ASTM Liquid-in-Glass Thermometers
the American Chemical Society, where such specifications are
3. Summary of Test Method
available.
3.1 The test specimen is agitated by rotating axially at 100
6.2 Hydrochloric Acid, 10 vol %.
rpm at an angle of 30° from the horizontal, under an initial
6.3 Silicon Carbide Abrasive Cloth, 100-grit with cloth
backing.
This test method is under the jurisdiction of ASTM Committee D27 on
6.4 Acetone, cp.
Electrical Insulating Liquids and Gases and is the direct responsibility of Subcom-
mittee D27.06 on Chemical Test.
Current edition approved July 15, 2007. Published August 2007. Originally
approved in 1962. Last previous edition approved in 2001 as D2112–01a. DOI: Reagent Chemicals, American Chemical Society Specifications, American
10.1520/D2112-01AR07. Chemical Society, Washington, DC. For Suggestions on the testing of reagents not
For referenced ASTM standards, visit the ASTM website, www.astm.org, or listed by the American Chemical Society, see Annual Standards for Laboratory
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
Standards volume information, refer to the standard’s Document Summary page on and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
the ASTM website. MD.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2112 − 01a (2007)
determine by difference the water retained in the system. The
coils are now ready for use. This procedure has been found to
be acceptable for treatment of commercially available,
prepackaged, preformed coils that meet the requirement de-
scribed in this test method. Use a new coil for each test
specimen.
8.3 Cleaning of Vessel— Wash the vessel body, lid, and
inside of vessel stem with hot detergent solution and with
water. Rinse inside of stem with 2–propanol and blow dry with
clean dry air. An alternative cleaning solution is the use of a
50/50 volumetric blend of methanol and acetone; it has been
found to be effective in cleaning sludge from the vessel. If the
vessel body, lid, or inside of stem smells sour after simple
cleaning, wash with alcoholic KOH solution and repeat as
before (see Note 2).
NOTE 2—Insufficient cleaning of the vessel may adversely affect test
FIG. 1 Rotating Vessel Oxidation Test Apparatus
results.
9. Procedure
6.5 2-Propanol, 99 vol %, refined.
9.1 Charging—Weigh 50 6 0.5 g of oil sample into the
6.6 Liquid Detergent.
container, add 5 mL of distilled water, and cover with a 2-in.
6.7 Oxygen, 99.5 %, with pressure regulation above 90 psi
(51-mm) watch glass or a 2 ⁄4-in. (57.2-mm) PTFE disk with
(620 kPa). (Warning —Oxygen vigorously accelerates com-
one or four holes and retaining spring. If rinse water is present
bustion).
in the container, compensate for it by using less added water
6.8 Potassium Hydroxide, Alcohol Solution (1 mass %)— based on the water retention determined in 8.3.Add5mLof
Dissolve 7.93 g of potassium hydroxide (KOH) pellets in 1 L
distilled water to the vessel and slide the test specimen
of 99 % refined 2-propanol. containerandcoverlidintothevesselbody(seeNote3).Apply
a thin coating of silicone stopcock grease to the O-ring vessel
6.9 Silicone Stopcock Grease.
seal located in the gasket groove of the vessel lid to provide
6.10 Wire Catalyst— AWG No. 14 (0.0641-in. (1.628-mm)
lubrication, and insert the lid into the vessel body. Place the
diameter) electrolytic copper wire 99.9 % purity, conforming
vessel cap over the vessel stem, and tighten by hand. Cover the
to Specification B1. Soft-drawn copper wire of an equivalent
threads of the gage-nipple with a thin coating of stopcock
grade may also be used.
grease or TFE-fluorocarbon, or both, and screw the gage into
the top-center tap of the vessel stem. Flush the vessel twice
7. Hazards
with oxygen supplied to the vessel at 90 psi (620 kPa) and
7.1 Consult Material Safety Data Sheets for all materials
release to the atmosphere. Adjust the regulating valve on the
used in this test method.
oxygen supply tank to 90 psi at a room temperature of 25°C
(77°F). For each 2.8°C (5.1°F) above or below this
8. Preparation of Apparatus
temperature, add or subtract 1 psi (7 kPa) unit to attain the
8.1 Catalyst Preparation—Immediately before use, polish
requiredinitialpressure.Fillthevesseltothisrequiredpressure
the copper wire with silicon carbide abrasive cloth and wipe
and close the inlet valve securely by hand. If desired, test the
freefromabrasiveswithacleandrycloth.Windapproximately
vessel for leaks by immersion in water (see Note 4). Prepare a
3 m of the wire into a coil having an outside diameter of 44 to
duplicate test specimen in exactly the same way.
48 mm and stretched to a height of 40 to 42 mm. Clean the coil
NOTE 3—The water between the vessel well and the test specimen
thoroughly with acetone and allow it to air-dry. Immediately
container aids heat transfer.
after air drying, insert the coil with a twisting motion into the
NOTE4—Ifthevesselwasimmersedinwatertocheckforleaks,drythe
glass test specimen container. Handle the coil only with clean outside of the wet vessel by any convenient means such as an air blast or
a towel. Such drying is advisable to prevent subsequent introduction of
tongs to avoid contamination. Weigh the coil and the container
free water into the hot oil bath, which would cause sputtering.
to the nearest 0.1 g and record the weight. Prepare a new coil
9.2 Oxidation—Bring the heating bath to the test tempera-
for each test specimen.
tureof140°Cwhilethestirrerisinoperation.Insertthevessels
8.2 Alternative Method of Catalyst Preparation—Wind ap-
into the rotating carriages and note the time. If an auxiliary
proximately3mof copper wire into a coil of the dimensions
heater is used, keep it on for the first 5 min of the run and then
specified in 8.1, and add to the glass container. Weigh the coil
turn it off (see Note 5).Allow the bath temperature to level out
and container to the nearest 0.1 g and record the weight. Wash
at the test temperature; this must occur within 10 min after the
the coil by filling the container above the level of the coil with
vessels are inserted. Maintain the test temperature within
10 % hydrochloric acid by volume for 30 s. Discard the acid
60.1°C (see Note 6).
and rinse the coils three times with tap water followed by three
times with distilled water. Reweigh the coil and container and NOTE 5—The time for the bath to reach the operating temperature after
D2112 − 01a (2007)
FIG. 2 Schematic Drawing of Rotary Vessel
insertion of the vessels may differ for different apparatus assemblies and
appreciable variations in this speed could cause erratic results.
should be observed fo
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