Panametrics CGA 351, Руководство пользователя, Страница: 9 / 119

CGA 351 User’s Manual 3
Chapter 1.
1.1.3 The Sample System
In addition to the components supplied with the CGA 351, an external sample system may be required to ensure that
the analyzer is fed a properly conditioned sample or calibration gas stream. In particular, the gas must be clean and
dry, and it must be delivered to the analyzer at atmospheric pressure.
Note: A suitable sample system, which will be supplied completely assembled on its own mounting plate, may be
ordered directly from the factory.
Commonly used sample system components include filters, pressure regulators, pressure gauges, by-pass loops,
and sample pumps. It is recommended that stainless steel construction be used for all wetted parts of the sample
system. A typical sample system is shown in Figure 3 below.
Figure 3: Typical Sample System
1.1.4 Principles of Operation
A gas sample is drawn into the inlet port of the analyzer by gas diffusion and a forced flow determined by the
external sample system. The sample gas then flows through a ceramic inlet tube and into the annular space
between the inlet tube and the inside of the zirconium oxide oxygen sensor. The flowmeter on the outlet port and the
needle valve on the inlet port are used to adjust the sample flow rate to 400 ± 40 cc/min.
SAMPLE
INLET
SAMPLE
OUTLET
INLET
CAL-GAS
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51
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