Thermo Scientific 43iQ, Instruction Manual

Page: 149 / 284

Calibration
Equipment Required
Thermo Scientific 43iQ Instruction Manual 4-3
A cylinder gas dilution system, shown in Figure 4–1 , can be constructed.
All connections between components in the system should be made with
glass, SS, PTFE or other non-reactive material.
The air flow controller should be capable of maintaining a constant air flow
within ±2% of the required flow rate. The SO
2
flow controller should be
capable of maintaining constant SO
2
flows within ±2% of the required flow
rate. Ensure both flow controllers are properly calibrated. The pressure
regulator for the standard SO
2
cylinder must have a non-reactive
diaphragm and internal parts and a suitable delivery pressure.
In order to obtain an accurate dilution ratio in the dilution method used
for calibration, the flow rates must be regulated to 1%, and be measured to
an accuracy of at least 2%. The meter and controller can be two separate
devices, or combined in one device. The user's manual for the meter should
be consulted for calibration information.
Additional information on the calibration of flow devices can be found in
the Quality Assurance Handbook
1
. It should be noted that all flows should
be corrected to 25 °C and 760 mmHg, and that care should be exercised in
correcting for water vapor content.
Figure 4–1. Cylinder Gas Dilution System
Cylinder Gas Dilution
External Flow Meter(s)
and Controller(s)