ASTM D5773 Standard Test Method for Cloud Point of Petroleum Products and Liquid Fuels (Constant Cooling Rate Method)
11. Procedure
11.1 Inspect the specimen cup to ensure it is clean and dry. If not, clean the cup (see 11.3).
11.2 Deliver 0.15 mL +/- 0.01 mL of specimen into the specimen cup. Pipette, syringe, or precision positive-displacement devices are suitable for use in delivering the specimen.
11.3 Clean the specimen out of the cup. The cup must be cleaned to the point where no visible droplets of specimen remain in the cup. Non-abrasive absorbent materials such as cotton swabs are suitable for use in cleaning the specimen cup. Cleaning solvents able to clean the specimen and compatible with the components of the apparatus can also be used. Naphtha, hexane, heptane, and toluene are suitable as cleaning solvents.
11.4 Repeat steps 11.2 and 11.3.
11.5 Carefully measure 0.15 mL +/- 0.01 mL of specimen into the specimen cup.
11.6 Close and lock the test chamber lid.
11.7 Select the PRE-HEAT menu on the apparatus if the expected cloud point is less than 14 °C below the specimen ambient temperature. The specimen ambient temperature is displayed on the front panel of the apparatus. With this selection, the apparatus will automatically heat the specimen to a starting temperature of 50 °C prior to cooling. If the PRE-HEAT menu is not selected, the apparatus will cool the specimen from ambient temperature without any initial heating. When the cloud point is expected to be higher than 35 °C, select a higher starting temperature according to manufacturer's instructions. The highest starting temperature that can be programmed is 70 °C.
11.8 Start the operation of the apparatus in accordance with the manufacturer's instructions.The apparatus will allow the flow ofliquid cooling medium, ifrequired, (see Note 4) and the flow of purge gas through the apparatus. (Warning - The apparatus will display appropriate warning signals if any of these flows are not properly established. Refer to manufacturer's operating manual for corrective procedures.)
11.9 The specimen is heated if specified as described in 11.7. It is then cooled by the Peltier device while the optical detectors continuously monitor the specimen for the appearance of a cloud of wax crystals. The measurement is automatically terminated once the cloud point is detected.
11.10 When the measurement is complete, the automatic cloud point value per Test Method D5773 will be displayed on the front panel of the apparatus.
11.11 Open the test chamber lid to access the specimen cup and clean the specimen out of the cup (see 11.3).
