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MRK-D-0048 V4
Aeroqual Dust Sentry / AQS User Guide
Page | 63
12 Appendix
12.1 Gas module design
O
3
NO
2,
VOC
Figure 12-1 Gas module sizes and key components labelled (Modules may vary from that shown)
The list of gas modules available for integration in to the monitor is provided in Table 12-1.
GAS
MODULE
RANGE
(PPB)
RE
S
OL
UT
IO
N
(P
P
B
)
S
E
NS
OR
T
Y
P
E
M
ODULE
S
IZ
E
MODULE
FLOW
RATE
NOISE
L
OWE
R
DE
T
E
CT
A
B
L
E
L
IM
IT
(
P
P
B
)
PRECISION
L
INE
A
RIT
Y
%
OF
F
.S
DRIFT 24
HOUR
EXPECTED
MODULE
LIFETIME
ZERO (PPM)
SPAN % OF
READING
Zero / (PPB)
SPAN % OF FS
O
3
0
– 500
ppb
0.1
GSS
Small
110
– 130
ml / min
-1
<1;
<1%
1
< 2% of reading or
2 ppb
< 1.5
%
1;
0.2 %
2
– 3 years
NO
2
0
– 500
ppb
0.1
GSE
Medium
55
– 65
ml / min
-1
<1;
<1%
2
< 2% of reading or
3 ppb
< 2.0
%
2;
1 %
2
– 3 years
VOC
0
– 30
ppm
10
PID
Medium
140
– 160
ml / min
-1
<100;
<0.20 or 1%
<50
< 2% of reading or
20 ppb
< 2.0
%
100;
1 %
2
– 3 years
Table 12-1 Gas modules available for integration in to the monitor
NOTE:
O
3
and NO
2
Modules have no serviceable parts. The VOC analyzer module uses a replaceable 10.6
eV UV lamp, if the lamp needs replacing contact the Aeroqual distributor in your local country for
technical support.
Gas Module design
Gas modules come in two different designs. These two designs are shown schematically in Figure 12-1. A list
of which gas modules use which design is given in Table 12-1.
Direct design
(Ozone): The gas is passed directly to the sensor continuously.
Zero switching design
(VOC and NO
2
): The module uses a solenoid to switch between a zero path
which removes the target gas and creates a “zero” or baseline measurement, and a measurement
path which measures the ambient air. The final measurement in ppm is an arithmetic combination of
the zero and sample measurement. This technique is referred to as Automatic Baseline Correction.