11. Procedure
11.1 Weigh 100.0 +/- 0.1 g of the coke fraction to be tested into a container. Pour the coke slowly and consistently through a funnel into the graduated cylinder. Total transfer time must be 70 to 100 s at a rate of 10 to 14 g/10 s. A suggestion is the use of a vibratory feeder or other device for the slow and consistent introduction of the coke fraction into the graduated cylinder. The importance of this step on the density value cannot be overemphasized. A rapid pour results in a higher volume than a slow pour and a part of the difference in volume is retained through the vibrating step.
11.2 Fit the rubber stopper tightly to the top of the graduate.
11.3 Place the graduate inside the retaining ring on the vibrator. Do not vibrate the graduated cylinder while adding the coke fraction into the graduated cylinder.
11.4 Vibrate for 5 min at a dial setting giving an amplitude of 0.20 to 0.22 mm (peak) at 60 Hz.
11.5 Measurement ofCompacted Volume:
11.5.1 Choose and record a line on the graduate below the top of the compacted sample column from which to measure the height of the sample. This will be known as the base line. For example, if the top of the sample column is near the 100-mL mark, the 90-mL mark may be chosen for the base line.
11.5.2 If deemed necessary (see 10.2), consult the table of indicated volume versus true volume and use the true volume at the base line.
11.5.3 Using a small metric rule, measure the distance from the base line to the top of the compacted column at eight points around the graduate. These distances are measured to the nearest 0.5 mm. Record and average the measurements.
11.6 Repeat the procedure, beginning at 11.1, with a second 100.0-g sample.
12. Calculations
12.1 Calculate the volume as follows:
Volume, mL = (A x B) + C
where:
A = average sample height from base line, mm,
B = calibration factor, mL/mm, and
C = base line, mL, corrected for graduated cylinder error, if necessary (see 10.2).
Average the values for the two determinations.