Micromeritics 1305 Operator's Manual page 35

Model 1305 MultiVolume Pycnometer
14. Place the PREP/TEST valve in the TEST position.
15. Allow the pressure to fall to zero and stabilize, correcting the pressure dis-
play with the ZERO control as necessary.
16. Place the PREP/TEST valve in the PREP position, ensuring that the zero
does not shift. If a shift occurs, return the valve to the TEST position and re-
peat Step 15.
17. Place the VENT valve in the CLOSE position, disregard any change of
pressure.
18. Place the FILL valve in the OPEN position and fill the chamber to 19.500
±0.200 psig as shown on the pressure indicator.
19. Place the FILL valve in the CLOSE position and allow the pressure to equili-
brate; record it as P
for most samples.
20. Immediately place the PREP/TEST valve in the TEST position and allow the
pressure to equilibrate; record it as P
sec) give best results for most samples.
21. Place the VENT valve in the OPEN position. If light powders are being ana-
lyzed, first close the VENT RATE valve (turn counterclockwise); then gradu-
ally open it as the pressure approaches zero.
22. Return to Step 15 if multiple determinations are to be made on this sample.
23. Remove the sample cup using the bent-end probe provided in the accessory
kit. Hook the probe in the hole in the upper lip of the cup and pull upward
until the cup can be grasped with fingers.
•
If a new sample is to be analyzed, return to Preparing and Weighing the
Sample.
•
If the instrument is to remain idle for an extended period (days), close the
sample chamber and shut off the helium supply. Refer to Turning Off the
Analyzer in this chapter for the proper shutdown procedure.
When all samples have been run, proceed to the next section for instructions on
calculating the results from the pressures recorded.
Jun 99
. Short times (approximately 15-30 sec) give best results
1
. Short times (approximately 15-30
2
Performing an Analysis
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