Teledyne 9110TH - Nitrogen Oxides Analyzer - Manual (Page 52)

Model 9110TH NOx Analyzer Getting Started
Teledyne Analytical Instruments 32
3.5.3.1. Ambient Zero/Ambient Span Valves (OPT 50A)
The Model 9110TH/M NO
x
analyzer can be equipped with a zero/span valve option for controlling the flow of
calibration gases generated from external sources. This option contains two solenoid valves located inside the
analyzer that allow the user to switch either zero, span or sample gas to the instrument’s sensor.
The user can control these valves from the front panel keyboard either manually or by activating the instrument’s
CAL or AutoCal features (Section 5.8). The valves may also be opened and closed remotely through the serial
ports (Section 4.11) or through the external, digital control inputs (Section 4.15).
This option also includes a two-stage, external zero air scrubber assembly that removes all NO and NO
2
from
the zero air source (ambient air). The scrubber is filled with 50% Purafil Chemisorbant ® (for conversion of NO to
NO
2
) and 50% activated charcoal (for removal of NO
2
). This assembly also includes a small particle filter to
prevent scrubber particles to enter the analyzer as well as two more rear panel fittings so each gas can enter the
analyzer separately.
Figure 3-19 and Figure 3-20 show the internal, pneumatic layouts with the zero/span valve option installed for a
Model 9110TH and 9110TM respectively.
O3
FL
OW
SENSOR
Fil
ter
NO
X
Exh
aus
t
Sc
rubb
er
EX
HA
US
T
MA
NI
F
O
LD
Figure 3-19: 9110TH – Internal Pneumatics with Ambient Zero-Span Valve Option 50A