Rae QRAE PLUS PGM-2000, Руководство по эксплуатации и техническому обслуживанию

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PROGRAMMING
4-6
Pumped Instruments
The preferred calibration methods for monitors with pumps are
ones that maintain the gas at atmospheric pressure. Such
methods include the open cup, open tube, or “Tee” methods, in
which the calibration gas flow is higher than the pump draw,
and excess gas flows out freely beside the inlet probe.
Suggested calibration connections are indicated below.
Alternately, to save gas, connect the monitor directly to the gas
cylinder using a demand-flow regulator. Calibration through
such a regulator will produce similar results to the open tube
methods, but special corrosion-resistant demand-flow
regulators are recommended for reactive gases such as Cl
2
and H
2
S. The monitor can also be calibrated from a gas sample
bag (Tedlar

bag), or directly from a cylinder through a fixed-
flow regulator with a flow rate between 0.5 and 1.0 liters per
minute, although the latter method is less accurate than the
other methods by a few percent.
Figure 9. Calibration Connection
Calibration Cup
Gas Cylinder
QRAE PLUS
Probe with Filter
(Insert as far as
possible)
Regulator