ASTM D2112 for oxidation stability of inhibited mineral insulating oil
ASTM D2112 standard test method for oxidation stability of inhibited mineral insulating oil by pressure vessel
8. Preparation of Apparatus
8.1 Catalyst Preparation - Immediately before use, polish the copper wire with silicon carbide abrasive cloth and wipe free from abrasives with a clean dry cloth. Wind approximately 3 m of the wire into a coil having an outside diameter of 44 to 48 mm and stretched to a height of 40 to 42 mm. Clean the coil thoroughly with acetone and allow it to air-dry. Immediately after air drying, insert the coil with a twisting motion into the glass test specimen container. Handle the coil only with clean tongs to avoid contamination. Weigh the coil and the container to the nearest 0.1 g and record the weight. Prepare a new coil for each test specimen.
8.2 Alternative Method of Catalyst Preparation - Wind approximately 3 m of copper wire into a coil of the dimensions specified in 8.1, and add to the glass container. Weigh the coil and container to the nearest 0.1 g and record the weight. Wash the coil by filling the container above the level of the coil with 10 % hydrochloric acid by volume for 30 s. Discard the acid and rinse the coils three times with tap water followed by three times with distilled water. Reweigh the coil and container and 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, pre-packaged, preformed coils that meet the requirement described 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 results.
