Figure 8-8
The H
S protection function over time
2
8.5.3
Probe purging function
Hydrogen sulfide measurement: Purging function of 50 vpm probe
Hydrogen sulfide (H
other gases. A selectable protection function has been implemented (see section Probe
protection function (Page 157)) since H
concentration impair the functionality and service life of the H
additionally been integrated for the 50 vpm probe, enabling a discontinuous measurement
above its permissible continuous concentration.
The permissible continuous concentration is 12.5 vpm. Although a measurement above such a
concentration is still correct, the probe is damaged after a certain period. This period can be set
in accordance with the experience gained using the sensor between 10 und 20 minutes using
the AUTOCAL purge time (the purging duration corresponds to twice the AUTOCAL purge time).
For this reason measurements above a concentration of 12.5 vpm must be carried out
discontinuously and alternately with purging gas. The probe can be used for a measurement
again following a purging time of equal duration with air.
ULTRAMAT 23
Equipment Manual, 04/2022, A5E37100388-012
8.5 Automatically executed functions of the H2S sensors
S) is a corrosive gas, especially in wet condition and in combination with
2
S concentrations above the permissible continuous
2
S probes. A purging function has
2
Functions
159