QUANTACHROME INSTRUMENTS MVP-6DC, Operating Manual, Page: 18 / 21

21. Repeat steps 3-14 and calculate the small cell volume using equation (12).
( )
[ ]
1 ' '
2 1
−
small P small P small
V
= small
V
R C
(12)
Where:
P
1
′
small
= pressure in V
R
small
with
no
sphere in the cell.
P
2
′
small
= pressure in V
R
small
+ V
C
small
with
no
sphere in the cell.
22. Remove the small sample cell and adapter and insert the micro adapter sleeve, micro sample
cell and both micro calibration spheres.
23. Close toggle valves I and II.
24. Open the “GAS FLOW IN” toggle valve until the pressure is approximately 17 (psi). Then
close the “GAS FLOW IN” toggle valve.
25. When the display is stable, note the pressure reading.
26. Turn the selector valve to "CELL".
27. When the display is again stable, note the new pressure reading.
28. Vent both the reference volume and cell holder by opening the "VENT" toggle valve.
29. Remove both calibration spheres from the micro cell and repeat steps 24-28 noting the
pressures with the selector valve in "REF" and "CELL" positions.
30. Calculate the volume of the micro reference volume (V
R
micro) using equation (13).
( )
[ ]
( ) [ ]
1 / 1 /
2 1
'
2
'
1
− − −
=
micro P micro P micro P micro P
micro V
micro V
cal
R
(13)
Where:
V
cal
micro
= combined volume of both micro calibration spheres
P ′
1
micro
= pressure in V
R
micro
with
no
spheres in the cell
P ′
2
micro
= pressure in V
R
micro
+ V
C
micro
with
no
spheres in the cell.
P
1
micro
= pressure in V
R
micro
with the calibration spheres in the cell.
P
2
micro
= pressure in V
R
micro
+ V
C
micro
with the spheres in the cell.