Micromeritics 1305 Operator's Manual page 51

Model 1305 MultiVolume Pycnometer
The Multivolume Pycnometer 1305 is a gas displacement pycnometer, a type of
instrument which measures the volume of solid objects of irregular or regular
shape whether powdered or in one piece. A greatly simplified diagram of the in-
strument is shown in Figure A1-1.
Assume that both V
temperature T
vated pressure P
where
n
C
R
T
a
Figure A1-1. Simplified Block Diagram of MultiVolume Pycnometer 1305
The mass equation for the expansion volume is
where
n
E
Jun 99
THEORY
and V
CELL
, and that the valve is then closed. V
a
. The mass balance equation across the sample cell, V
1
P1 (V - V ) = n
CELL SAMP
= the number of moles of gas in the sample cell,
= the gas constant, and
= the ambient temperature.
P V = n RT .
a EXP E a
= the number of moles of gas in the expansion volume.
are at ambient pressure P
EXP
CELL
RTa
C
Appendix A
, are at ambient
a
is then charged to an ele-
is
CELL
(1)
(2)
A-1