ASTM D6892 Test Method for Pour Point of Petroleum Products (Robotic Tilt Method)
11. Procedure
11.1 Fill the test jar up to the marked line with the specimen. When necessary, heat the sample in a water bath or oven until it is just sufficiently fluid to pour into the test jar.
NOTE 3 - Residual fuels have been known to be sensitive to thermal history. In the case where a residual fuel sample is tested, refer to Test Method D97 for sample treatment.
11.2 Insert the test jar into the apparatus and start the test in accordance with the manufacturer's instructions.
11.3 When the expected pour point is known to be above -33°C, preselect a starting temperature which is at least 9°C above the expected pour point, but to at least 45°C.
11.4 When the expected pour point is known to be at or below -33°C, preselect a starting temperature of 45°C.
11.5 When the expected pour point is not known, preselect a starting temperature of 45°C. When the expected pour point is not known and the sample must be heated to allow transfer into the test jar, preselect a starting temperature corresponding to the preheat temperature. (Warning - Exercise care when selecting starting temperatures above 45°C. Samples which are fluid at ambient room temperature can also have a low temperature flash point. Use higher start temperatures only on samples known to be solid near ambient room temperature.)
11.6 Preselect the testing interval of 1 or 3°C as determined by your standard laboratory practice. Should the user wish to provide results with a similar format to Test Method D97 or IP 15, then testing at a 3°C interval shall be selected.
11.7 Once the operation of the apparatus is initiated, the specimen is heated to the temperature preselected by the operator. The cooling/heating block shall be regulated in accordance to the programmed temperature settings obtained from Table 1. The instrument shall automatically change the block temperature in accordance with the specimen temperature (according to Table 1). The time required to move the jacket temperature from one temperature level to the next lower level shall not exceed 180 s.
11.8 Beginning at the preselected start testing temperature, the test jar shall be lifted out of the block assembly, tilted toward a horizontal position, until movement of the surface of the specimen is detected by the optical system, and then returned to the block assembly. This complete operation shall take no longer than 3 s when specimen surface movement is observed. This operation shall be repeated at each subsequent lower temperature interval that has been preselected by the operator. The operations shall be repeated until the test jar is tilted horizontally for longer than 3 s and no movement of the surface of the specimen is detected for a maximum of 5 s. If movement is detected between 3 to 5 s, the test jar is returned to the block assembly and the operations continued.
11.9 Record the temperature measured at the last tilting interval as the no-flow point.
NOTE 4 - Some apparatus are capable of returning the test jar to the block assembly and the specimen can be reheated to a previously programmed temperature to facilitate disposal and cleaning.
11.10 Remove the test jar from the apparatus and clean the test jar and apparatus with suitable solvents and then dry with clean air according to the manufacturer's instructions.
