Revision 14
27 August 02, 2019
2.8 Sample Flow Related Components
The system contains a number of components that control the flow of the sample and
condition it. The sample flows though the humidifier and rotameter and finally out of the
analyzer through the eductor.
2.8.1 Sample Humidifier
The reaction between lead acetate and hydrogen sulfide is improved if the hydrogen sulfide-
containing sample gas is humidified prior to coming into contact with the lead acetate. The
standard Nafion permeable membrane humidifier for the system is shown in Figure 2-10 and
the humidifier used with the total sulfur option is shown in Figure 2-11.
Figure 2-10: Nafion Humidifier
Figure 2-11: Total Sulfur Option Humidifier
The humidifier is located behind the lower access door on the front of the chassis. The door
has a hole through which the liquid level in the humidifier can be observed. The humidifier is
filled with a 5% Acetic Acid solution. The acid solution is used to keep the humidifier free of
algae, as well as to lower the freezing point to several degrees below zero Celsius. In the
permeable membrane humidifier, sample gas passes through the tube at the top of the
humidifier. The tube is made of Nafion, a selectively permeable material that allows water
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