Micromeritics TriStar II 3020 - C. CALCULATIONS; Relative Pressure Calculations

TriStar II 3020 Appendix C
302-42828-01 - Dec 2012 C-1
C. CALCULATIONS
This appendix contains the calculations used in the analysis program.
Saturation Pressure
Saturation pressure (Po) is selected on the Po and Temperature Options dialog. It may be entered or
measured in the Po tube or on port 3.
• If entered, Po = user-entered value
• If measured, Po = equilibrated pressure reading after saturating Po tube or the sample tube
Relative Pressure Calculations
Po
I
Po
1
Po
2
Po
1
–t
I
to
1
–
to
2
to
1
–
----------------------------------------------------------
+=
If Po was measured at intervals in the Po tube and several data points were collected in the interval:
• For points taken before the previous Po measurement,
• For points taken after the previo
us Po, use the previous Po:
Po
I
= Po
1
If Po was entered, use the entered Po:
Po
I
= Po
E
P
rel
1
P
1
Po
I
--------
=
Calculate relative pressure for the I
th
data point:
where
Po
I
= saturation pressure for the I
th
data point (mmHg)
Po
1
= most previous measured saturation pressure before I
th
data point (mmHg)
Po
2
= first measured saturation pressure after the I
th
data point (mmHg)
Po
C
= calculated Po
Po
E
= entered saturation pressure (mmHg)
t
I
= time when the I
th
data point was taken (minutes)
to
1
= time when Po
1
was measured (minutes)
to
2
= time when Po
2
was measured (minutes)