Teledyne T200 User Manual page 48

In addition to tubing, pressure, venting, and exhaust requirements set out in Section 2.3.2.1,
attach the following pneumatic lines:
S G
AMPLE
Connect a sample gas line to the SAMPLE inlet, and:
In applications where the sample gas is received from a pressurized manifold and the
•
analyzer is not equipped with one of the T200's pressurized span options, a vent must
be placed on the sample gas line.
C
ALIBRATION
Internal:
•
Uses the IZS generator.
•
• External (for precision calibration):
• CAL GAS & ZERO AIR SOURCES: The source of calibration gas is attached to the
SAMPLE inlet.
V
ENTING
Vent the Sample line if input is pressurized.
I S
NTERNAL
The primary component of the internal span option is a permeation tube containing liquid
NO As zero air is passed over a permeable membrane on the end of the tube, molecules
2.
of NO slowly pass through the membrane mixing with the zero air.
2
The resulting concentration of the NO
• size of the membrane (the larger the area of the membrane, the more permeation
occurs)
• temperature of the NO
the pressure inside the tube, thereby increasing the rate of permeation)
• flow rate of the zero air (if the previous two variables are constant, the permeation
rate of the NO
of zero air produces higher concentrations of NO
The permeation tube enclosure is heated to a constant 50° C (10° above the maximum
operating temperature of the instrument) in order to keep the permeation rate constant. A
thermistor measures the actual temperature and reports it to the CPU for control feedback.
The flow rate of zero air across the permeation tube is maintained at 50 ± 10 cc/min by a
critical flow orifice located in the analyzer's exhaust manifold.
46 Teledyne API T200 NO/NO
S
AS OURCE
G S
AS OURCES
G G
PAN AS ENERATION
(increasing the temperature of the permeation tube increases
2
into the zero air stream will be constant; therefore, a lower flow rate
2
/NO Analyzer with NumaView™ Software
2 x
span gas is determined by three factors:
2
)
2
083730200A DCN7962