ASTM D6082 High Temperature Foaming Characteristics of Lubricating Oils
9. Preparation of Apparatus
9.1 Thorough cleansing of the test cylinder, gas diffuser, and air-inlet tube is essential after each use to remove any additive remaining from previous tests which can seriously interfere with results of subsequent tests.
9.1.1 Cylinder - Rinse the cylinder with heptane (Warning: See Note 7), followed by directing a current of compressed air into the cylinder. Wash the cylinder with a suitable detergent. Rinse the cylinder in turn with distilled water, then acetone (Warning: See Note 6), and dry with a current of compressed air or in a drying oven. Interior cylinder walls that drain distilled water cleanly, that is without drops forming, are adequately cleaned.
NOTE 9 - Certain detergents are notorious for adhering to glass, therefore it is important to realize that such a circumstance can affect the test result. Several rinsings with water and acetone may be required.
9.1.2 Gas Diffuser and Air Tube - Clean the gas diffuser by washing it with toluene (Warning: See Note 7) and heptane. Immerse the gas diffuser in about 300 mL of toluene. Flush a portion of the toluene back and forth through the gas diffuser at least five times with vacuum and air pressure. Repeat the process with heptane. After the final washing, dry both tube and gas diffuser thoroughly by forcing clean air through them. Wipe the outside of the air-inlet tube first with toluene, then with a clean cloth moistened with heptane, and finally with a clean dry cloth. Do not wipe the diffuser.
NOTE 10 - Certain samples may contain ingredients which may not be adequately removed by this process and, because these can affect the next test, more rigorous cleaning may be required; this is recommended. When alternate diffuser cleaning methods are used certain cautions should be observed: (1) Non-metallic diffusers may have absorbed as well as adsorbed these interfering ingredients or the cleaners, or both, and this shall be considered before proceeding to the next test; (2) So that all tests performed start off under the same circumstances, when alternate diffuser cleaning methods are used, the final rinsing process shall be as detailed in 9.1.2; (3) See also Note 1. Gas diffuser permeability and porosity can change during use; therefore it is recommended that diffusers be tested when new and periodically thereafter, preferably after each use.
