Emerson Rosemount 936, Справочное руководство

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disturbances, such as fog, rain, etc., through a constant comparison with its dual spectral
beam.
2.3.3 Detected gases
The Rosemount 936 detects the following toxic gases and vapors according to their
unique spectral absorption in the UV solar blind range:
Ammonia (NH
3
)
A flammable and toxic gas that is highly irritating and colorless with a pungent odor.
The early detection of NH
3
is essential to prevent its toxic effects, such as respiratory tract
paralysis. In the ultraviolet (UV) band, NH
3
has a typical strong absorption in the solar blind
range of 189 nm to 210 nm that enables its fast and reliable detection at low
concentrations.
Hydrogen sulfide (H
2
S)
A flammable, poisonous gas with a characteristic smell of rotten eggs.
H
2
S is heavier than air and very dangerous to humans, causing collapse, coma, and death
from respiratory failure within a few seconds of inhalation.
Early detection of H
2
S is essential to prevent its toxic influence.
In the UV band, H
2
S has characteristically strong absorption in the solar blind range of
189 nm to 270 nm, which enables fast and reliable detection at low concentrations.
2.3.4 Ultraviolet (UV) source
The Rosemount 936 employs the latest generation of Xenon UV flash bulbs to provide
extended installation distance and maximum reliability.
2.3.5 Heated optics
The Rosemount 936 includes heated optics for the detector and source.
The heater increases the temperature of the optical surface by 5 to 8 °F (3 to 5 °C) above
the ambient temperature to improve performance in icing, condensation, and snow
conditions. Emerson has configured the heated optics to automatically operate when the
change in temperature requires heating (default).
However, you can also define the heated optics as one of the following modes:
1. Not operated (not an option source unit)
2. On continuously
3. Automatic, per temperature change (default)
See System setup .
When operated in Automatic mode, you can define the start temperature below which the
window will be heated (default 41 °F [5 °C]). You can define this temperature between 32
°F (0 °C) and 122 °F (50 °C). The heating stops when the temperature is 27 °F (15 °C) above
the start temperature.
Reference Manual Technical description
00809-0100-4036 October 2021
Rosemount 936 11