Micromeritics AccuPyc 1330, Руководство оператора, Страница: 94 / 115

When the valve is opened, the pressure will fall to an intermediate value, P
2
,
and the mass balance equation becomes
P
2
(
V
CELL
−
V
SAMP
+
V
EXP
) =
n
c
RT
a
+
n
E
RT
a
(3)
Substituting from equations (1) and (2) into (3):
P
2
(
V
CELL
−
V
SAMP
+
V
EXP
) =
P
1
(
V
CELL
−
V
SAMP
) +
P
a
V
EXP
(4)
or
(
P
2
−
P
1
) (
V
CELL
−
V
SAMP
) = (
P
a
−
P
2
)
V
EXP
(5)
then
V
CELL
−
V
SAMP
=
P
a
−
P
2
P
2
−
P
1
V
EXP
(6)
Adding and subtracting P
a
in the denominator and rearranging gives
−
V
SAMP
=
−
V
CELL
+
(
P
a
−
P
2
)
V
EXP
(
P
2
−
P
a
) −
(
P
1
−
P
a
)
(7)
Dividing by (P
a
- P
2
) in both the numerator and denominator
V
SAMP
=
V
CELL
−
V
EXP
−
1
−
P
1
−
P
a
P
a
−
P
2
(8)
or
V
SAMP
=
V
CELL
−
V
EXP
P
1
−
P
a
P
2
−
P
a
−
1
(9)
APPENDIX B AccuPyc 1330
B-2 September 1996