ASTM D6795 Standard Test Method for Measuring the Effect on Filterability of Engine Oils After Treatment with Water and Dry Ice and a Short (30 min) Heating Time
6. Apparatus
6.1 The apparatus consists of a 25 mL burette, a filter holder with 25 µm automotive oil filter paper, and a source of (69 +/- 2) kPa air pressure. Discs of filter paper are cut to fit the holder and installed (see Fig. 1).
6.1.1 Burette (glass or plastic), 25 mL, with polytetrafluoroethylene (PTFE) stopcock and (1.8 +/- 0.1) mm burette tip opening.
6.1.2 Air Regulator, capable of regulating air to a pressure of (69 +/- 2) kPa.
6.1.3 Filter Holder, with effective filter area approximately 0.8 cm2.
6.1.4 Automotive Oil Filter Paper, 25 mm, (25 µm porosity).
6.2 Blender, capable of 18 000 rpm +/- 10 % without the container.
6.2.1 Timer, capable of timing (30 +/- 1) s.
6.3 Container, 250 mL, with blade compatible with the blender.
6.4 Syringe, 1000 µL.
6.5 Dry Ice (solid carbon dioxide).
6.6 Mechanical Convection Oven, capable of maintaining (70 +/- 1) °C.
6.7 Sensors (or equivalent timing devices), capable of measuring sequential events to 1 s resolution.
6.8 Glass Jars, 60 mL, with inert lined lids.
7. Reagents
7.1 Purity of Reagents - Use reagent grade chemicals in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination.
7.2 Purity of Water - Unless otherwise indicated, references to water shall be understood to mean Specification D1193 Type III deionized water or water of equivalent purity.
7.3 TMC Reference Oils - These are available from the Test Monitoring Center.
8. Sampling
8.1 Take samples in accordance with the instructions in Practice D4057.
9. Preparation of Test Oil Sample and Filter
9.1 Mix (49.7 +/- 0.1) g of test oil, (0.3 +/- 0.05) g [(0.3 +/- 0.05) mL with the 1000 µL syringe] of deionized water and approximately 10 g of dry ice in the blender for (30 +/- 1) s at 18 000 rpm +/- 10 %. Cover the top of the container loosely to prevent oil spattering while allowing rapid vaporization of the dry ice.
9.2 Transfer the sample to a 60 mL wide-mouth glass bottle and place the loosely capped (1/4 turn) bottle in an oven at (70.0 +/- 1.0) °C for (30 +/- 2) min. Remove from the oven, tighten cap and allow to cool to room temperature (20 to 24) °C.
9.3 Store in dark at room temperature (20 to 24) °C.
9.4 Determine filterability (48 +/- 2) h after removing the sample from the oven.
9.5 Dry filters in an oven at (70 +/- 2) °C for (30 +/- 2) min and store in a desiccator until used.
