QUANTACHROME INSTRUMENTS MVP-6DC - Page 18

21. Repeat steps 3-14 and calculate the small cell volume using equation (12).
(
)
[
] 1''
21
−
smallPsmallP small
V
= small
V
RC
(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/
21
'
2
'
1
−−−
=
microPmicroPmicroPmicroP
microV
microV
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.