Thermo Scientific 43i, Инструкция по эксплуатации

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Calibration
Calibration Gas Generation
4-2 Model 43i Trace Level-Enhanced Instruction Manual Thermo Fisher Scientific
An absorbing column packed with activated charcoal is acceptable for
scrubbing SO
2
from ambient air. Ambient air is forced through a
laboratory gas absorption column packed with the charcoal and the SO
2
is
removed to acceptable levels (<0.5 ppb). The charcoal should be changed at
a minimum of every six months. It may be necessary to change the charcoal
more frequently depending on local conditions.
A calibration gas system capable of providing accurate levels of SO
2
calibration gas between zero and 80% of the full-scale range is required.
The calibration system must provide a flow rate of at least 0.8 LPM for an
instrument with the standard flow (instruments with higher flow rates will
require a higher minimum calibration system flow rate). All calibration gas
should be derived from local or working standards (such as cylinders of
compressed gas or permeation devices) that are certified as traceable to an
NIST primary standard.
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, Teflon®, 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.
Absorbing Column
Calibration Gas
Generation
Cylinder Gas
Dilution