Commercial Precision Dilution Systems; Permeation Tube System; Figure 4-2. Permeation Tube System - Thermo Scientific 42iQ Instruction Manual

Calibration
Calibration
Commercial Precision
Dilution Systems

Permeation Tube System

4-16 42iQ Instruction Manual
Commercial precision dilution systems are available which reliably and
accurately dilute a high concentration gas mixture to provide a reliable span
gas. A high concentration of NO
concentration range required.
The Thermo Scientific 146iQ Multi-gas Calibrator is one such system for
precision dilution.
Permeation tube systems which precisely maintain a set temperature to
within ±0.1 °C and hold a zero air flow rate to within ±0.5% can be used
for generation of span gas. The flow rate of the permeation system must be
at least 0.5 LPM for proper operation.
A permeation tube system, shown in
connections between components in the system should be made with glass,
PTFE, 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 NO output level is calculated from:
2
in air is precisely diluted to the
2
Figure 4–2 can be constructed. All
P x K
[ =
]
NO
2
OUT
F
T
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