13 Model 7500 Instruction Manual
Teledyne Analytical Instruments
(2) Sampling gas ow rate
A ow rate of sampling gas must be 1 L/min ±0.5 L/min. A ow meter should be provided as
shown in Fig. 3-2 to measure ow rate values.
(3) Preparation for standard gas
Prepare the standard gas for zero/span calibration.
No O2 meter Built in O2 meter Externally mounted
zirconia O2 meter
Zero gas N2 gas N2 gas Dry air or air (No
calibration performed
with CO2 meter)
Span gas except for O2 Gas with concentration
of 90% or more of full
scale
Gas with concentration
of 90% or more of full
scale
Gas with concentration
of 90% or more of full
scale
Span gas for O2 Gas with concentration
of 90% or more of full
scale
1 to 2% of O2 gas
(4) Purging of instrument inside
The inside of instrument need not be purged generally except for the following cases.
1. A combustible gas component is contained in sample gas.
2. Corrosive gas is contained in the atmospheric air at the installation site.
3. The same gas as the sample gas component is contained in the atmospheric air at the installation
site.
In such cases as above, the inside of analyzer should be purged with the air for instrumentation or N2.
Purging ow rate should be about 1L/min.
If dust or mist is contained in purging gas, it should be eliminated completely in advance.
(5) Pressure at sampling gas outlet
Pressure at the sampling gas outlet should be set to atmospheric pressure.