ASTM D3709 Standard Test Method for Stability of Water-in-Oil Emulsions Under Low to Ambient Temperature Cycling Conditions
5. Apparatus
5.1 Cold Box - A thermostatically controlled freezer or cold box capable of being maintained at -18 +/- 1.5°C (0 +/- 3°F).
5.2 Graduated Cylinder - A stoppered 100-mL glass cylinder graduated in 1.0-mL increments. The stopper should have a vent groove to prevent vacuum or pressure build-up during the test.
5.3 Pipet, 10-mL glass.
5.4 Microsyringe, 0.05-mL glass with a fixed needle, No. 19 gage, point style No. 3.
5.5 Glass Vials, approximately 30-mL size.
6. Preparation of Sample
6.1 To ensure uniformity of the sample, it should be mixed thoroughly before removing the quantity required for the test. Vigorous hand shaking or mechanical mixing for 3 to 5 min is recommended for litre-size containers or less.
6.2 Special difficulties arise in mixing and withdrawing representative samples from large containers. This is due to the nature of water-in-oil emulsions that are two-phase systems as distinct from truly homogeneous systems. Vigorous mechanical stirring for an extended period is the best means of achieving homogeneity. However, for unstable emulsions that have been in storage for some time there is no satisfactory way to obtain a representative sample.
