Ametek 5920 UHP User Manual page 20

Sample Flow
Schematic representations of the 5920's sample manifold are shown in Figures
1-2 through 1-5. These figures represent each of the four (4) operating states
used by the analyzer:
In normal operation of the analyzer (Figures 1-2 and 1-3), the sample gas
enters the analyzer and flows directly through the diaphragm valve (DV1); the
other two (2) diaphragm valves (DV2 and DV3) remain closed to isolate the
first purifier. DV4 is an isolation valve that is used to seal-off the outlet of the
purifier when there is no power/instrument air supplied to the analyzer.
The sample gas then passes through a high-purity Pressure Regulator that is
controlled by a Stepper Motor. After exiting the Pressure Regulator, the gas
flow splits into a Sample path and a Reference path. An orifice at the front end
of each path provides a pressure drop and balances the gas flow rate between
the two paths. Approximately half of the gas flows down each of the two
paths.
In the Reference path, the gas passes through a mass flow meter (MFM) that
is used to provide a control signal for the Stepper Motor-controlled Pressure
Regulator. The gas then passes through a purifier which removes any water
vapor. At this point, the gas that exits the purifier is considered to be a "dry"
Reference gas.
Sample Gas IN
DV1
DV2 DV3
Purifier
OPEN
CLOSED.
D V = Diaphragm Valve
S V = Solenoid Valve
MFM = Mass Flow Meter
Figure 1-2.
Flow during Reference cycle.
1-6 | 5920 UHP Moisture Analyzer
Gas A
Sample Gas
Pressure
Regulator
SPLIT
Gas B
SV3
MFM
Sample Gas Flow/Path
Reference Gas Flow/Path
Sensor
DV4
Purifier
PN 592047901 Rev YC
SV1
SV2