Teledyne 3020M - Explosion proof paramagnetic oxygen analyzer - Manual (Page 19)

2-5
Percent Paramagnetic Oxygen Analyzer Operational Theory 2
Teledyne Analytical Instruments
(0% 0
2
) - (Cross Interference Value) = Zero Point Value
0% -(-0.137) = +0.137%0
2
2.4 Sample System
The sample system delivers gases to the sensor from the analyzer gas
panel inlets. Depending on the mode of operation either sample or calibration
gas is delivered.
The Model 3020M sample system is designed and fabricated to ensure that
the oxygen concentration of the gas is not altered as it travels through the
sample system. The sample encounters almost no dead space. This minimizes
residual gas pockets that can interfere with low percent range analysis.
The sample system for the standard instrument incorporates ¼ inch tube
fittings for sample inlet and outlet connections at the rear panel. For metric
system installations, 6 mm adapters are supplied with each instrument to be used
if needed. The sample or calibration gas flowing through the system is moni-
tored by a flowmeter downstream from the sensor.
The gases delivered to the instrument should be at constant pressures and
flow rates and must exit freely into the ambient atmosphere. The Span, Zero
and Sample gases should be delivered at constant pressures of about 10 psig
(Range 5-20). The flow rate must be maintained at about 700 cc/minute (Range
600-1000) and must exit freely into atmospheric pressure.
Figure 2-4 is the flow diagram for the sampling system. In the standard
instrument, calibration gases (zero and span) can be connected directly to the
Sample In port by teeing to the port with appropriate valves. The shaded por-
tions of the diagram show the components added when the –C and/or –F
options are ordered. The solenoid valves, when supplied, are installed inside the
3020M enclosure and are regulated by the instruments internal electronics. The
flame arrestors, when supplied, are installed in the Gas Connector Panel.
Figure 2-4: Flow Diagram
Sample In
Span In
Zero In
Flowmeter
(Maintain at 700 cc/minute)
Exhaust Out
into athmosphere
Solenoid
Valves
Sensor
Components in the shaded area are in
the -C option (internal control valves)
only and are not shown in the piping
diagram above.
Needle Valves
to adjust the flow
Supplied at
constant
pressure
of 10 psig