C Sample Volume Equation Derivation C - Micromeritics ACCUPYC II 1345 Operator's Manual

C S V
AMPLE OLUME
10, 100, 350
AND
The AccuPyc II is a gas displacement pycnometer which measures the volume of solid objects of
irregular or regular shape whether powdered or in one piece. A greatly simplified diagram of the
instrument is shown below.
Sample volume is determined from the known cell and expansion volumes and from measured
pressures.
The cell and expansion chamber are initially at ambient pressure and the valve is closed. The cell is
then charged to an elevated pressure.
The ideal gas law gives:
where
n = moles of gas in the sample cell
c
R = the gas constant
T = temperature
V = cell volume
c
V = sample volume
s
V = expansion volume
x
P = initial cell pressure
1
Expansion volume:
AccuPyc II 1345 Operator Manual
134-42851-01 (Rev A) — Jan 2021
E
QUATION
CM 3
U
NITS
C Sample Volume Equation Derivation
D
ERIVATION
(1)
(2)
C - 1