7. Sampling
7.1 The test is very sensitive to small amounts of contamination. Take samples in accordance with Practice D 4057.
8. Preparation of Apparatus
8.1 Clean the graduated cylinder by removing any film of oil (or fluid) with a thorough rinsing with toluene or solvent with similar cleaning and solvency characteristics followed by a wash first with acetone and then with tap water. Clean the glassware with a suitable detergent (6.5). Rinse with tap water. Soak the cylinder in the detergent for at least 24 h. Rinse thoroughly with tap water and then with reagent water.
8.1.1 Check the glassware for cleanliness by adding reagent water to the cylinder and inverting it to drain the water. If the water drains with a smooth sheeting action and leaves behind no droplets, the glassware is clean for use. An additional soak in a mildly acidic solution may be necessary.
NOTE 1 - Alternately, new glassware may be used, provided that they are thoroughly rinsed with reagent water and meet the cleanliness defined by the sheeting action as described in 8.1.1.
8.2 Clean the stirring paddle and shaft with absorbent cotton or tissue wet with toluene or solvent with similar cleaning and solvency characteristics and air dry. Care shall be taken not to bend or misalign the paddle assembly during the cleaning operation.
9. Procedure
9.1 Heat the bath liquid to 54 more or less 1°C, 82 more or less 1°C or specified test temperature and maintain it at that temperature throughout the test. Add reagent water to the graduated cylinder to reach the 40-mL mark when at test temperature. Typically 39.5 mL of water at room temperature will expand to the 40-mL mark once the cylinder is placed in the bath at 54°C; 39 mL if heating the sample to 82°C. Invert the sample several times in the original container. Do not pour, shake, or stir samples to any greater extent than necessary to prevent air entrainment. Pour the oil (or fluid) under test into the same cylinder until the top level of the oil reaches the 80-mL mark on the cylinder when at test temperature.
9.2 If initial volumetric measurements are made at room temperature, expansion occurring at the elevated test temperature will have to be considered. For example, there will be a total volumetric expansion of about 2 to 3 mL at 82°C. Corrections to each volume reading at 82°C, therefore, should be made so that the total of the volume readings made for oils (or fluid), water, and emulsion does not exceed 80 mL. An alternative procedure which would avoid the corrections is to make the initial volumetric measurements at the test temperature.
9.3 A 1 % sodium chloride (NaCl) solution or synthetic seawater, as described in Practice D 1141 or Test Method D 665, may be used in place of distilled water when testing certain oils or fuels used in marine applications.
9.4 Secure the cylinder in place directly under the stirring paddle. Lower the paddle into the cylinder until the stop engages at the required depth. Start the stirrer and a stop watch simultaneously and adjust the stirrer, as required, to a speed of 1500 more or less 15 rpm. At the end of 5 min, stop the stirrer and raise the stirring assembly until it is just clear of the graduate. Wipe the paddle with a policeman, allowing the liquid thus removed to drop back into the cylinder. At 5-min intervals, or at the specification time limit identified for the product being tested, inspect the sample through the glass panel of the heating bath, and record the volumes of the oil (or fluid), water, and emulsion layers. If necessary, additional lighting, such as a backlight or an indoor flood light, may be used to aid the analyst in the inspection of the sample.
9.5 Several samples may be placed in the bath at the beginning of the first analysis. While the first sample is being observed, additional samples may be stirred. At no time during a sample inspection shall an additional sample be added to the heating bath.
