Teledyne 6200E - Sulfides Analyzer - Manual (Page 29)

Model 6200E Instruction Manual Getting Started
M6200E Rev: A1 29
NOTE
Maximum pressure of any gas at the sample inlet should not exceed 1.5 in-Hg above
ambient pressure and ideally should equal ambient atmospheric pressure.
In applications where the sample gas is received from a pressurized manifold, a vent
must be provided to equalize the sample gas with ambient atmospheric pressure before
it enters the analyzer. The vented gas needs to be routed outside the immediate area or
shelter surrounding the instrument.
3. Attach zero air and span gas supply lines as appropriate (see Figures 3-6 & 3.7). For this type
of analyzer, zero air and span gas are defined as follows:
Zero air and span gas inlets should supply their respective gases in excess of the 700 cc 3 /min
demand of the analyzer. Supply and vent lines should be of sufficient length and diameter to
prevent back diffusion and pressure effects.
SPAN GAS
• A gas specifically mixed to match the chemical composition of the type of gas being
measured at near full scale of the desired measurement range. In the case of H
2
S,
measurements made with the Teledyne Analytical Instruments Model 6200E UV
Fluorescence H
2
S Analyzer it is recommended that you use a span gas with a H
2
S
concentration equal to 90% of the measurement range for your application.
EXAMPLE: If the application is to measure between 0 ppb and 500 ppb, an appropriate
span gas concentration would be 450 ppb H
2
S in N
2
.
Cylinders of calibrated H
2
S gas traceable to NIST-Standard Reference Material specifications
(also referred to as SRM’s or EPA protocol calibration gases) are commercially available. Table
3-5 lists specific NIST-SRM reference numbers for various concentrations of H
2
S.
Some applications, such as EPA monitoring, require a multipoint calibration procedure
where span gases of different concentrations are needed. We recommend using a bottle of
calibrated H
2
S gas of higher concentration in conjunction with a gas dilution calibrator such
as a Teledyne Analytical Instruments Model 700. This type of calibrator precisely mixes a
high concentration gas from zero air (both supplied externally) to accurately produce span
gas of the correct concentration. Linearity profiles can be automated with this model and
run unattended over night.
Table 3-5: NIST-SRM's Available for Traceability of H
2
S & SO
2
Calibration Gases
NIST-SRM 4 TYPE
NOMINAL
CONCENTRATION
2730
2731 Hydrogen sulfide in N
2
Hydrogen sulfide in N
2
5000 ppb
20 ppm
1693a
1694a
1661a
Sulfur dioxide in N
2
Sulfur dioxide in N
2
Sulfur dioxide in N
2
50 ppm
100 ppm
500 ppm