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Calibration
Permeation Tube System
Commercial
Permeation Systems
4-4
Model 43i Trace Level-Enhanced Instruction Manual
A permeation tube system, shown in Figure 4–2 can be constructed. All
connections between components in the system should be made with glass,
Teflon®, or other non-reactive material.
The air flow controllers should be capable of maintaining a constant air
flow within ±2% of the required flow rate. Ensure all devices are properly
calibrated and that all flows are corrected to 25 °C and 1 atm.
Figure 4–2. Permeation Tube System
The SO
output level is calculated from:
2
Where:
[SO
]
= SO
output concentration in ppm
2
OUT
2
P = permeation rate in μg/min
F
= total flow rate of gas after mixing chamber (F
T
K (SO
) = 0.382 constant for SO
2
Commercial permeation systems, such as the Thermo Scientific Model 146
Multigas Calibration System, are available for this requirement. Refer to
the instrument instruction manual for more information.
P
x
K
[
]
=
SO
2
OUT
F
T
P
permeant
2
+ F
) in liters/minute
D
Thermo Fisher Scientific
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