ASTM D892 standard test method for foaming characteristics of lubricating oils
9. Preparation of Apparatus
9.1 Thorough cleansing of the test cylinder 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 - Flammable, vapor harmful.) Wash the cylinder with a suitable detergent. Rinse the cylinder, in turn, with distilled water, then acetone (Warning - Extremely flammable, vapors can cause a flash fire) and dry in a current of the compressed air or in a drying oven. Interior walls that drain the water cleanly, that is without drops forming, are adequately cleaned.
NOTE 10 - 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 with toluene (solvents with equivalent cleaning and solvency characteristics may be substituted for toluene.) 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 the tube and the gas diffuser thoroughly by forcing clean air through them. Wipe the outside of the air inlet tube, first with a cloth moistened with heptane, then a dry cloth. Do not wipe the gas diffuser.
NOTE 11 - 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.
