DURAG D-R 290, Руководство по эксплуатации

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4 | Product description
42 D-R 290
The housing is constructed of high-quality materials such as painted aluminium die-
castings and stainless steel (1.4301 or 1.4571).
All five units complement each other within the dust concentration and opacity moni­
toring system in the twin-beam alternating light process [
}
196] using the auto-colli­
mation principle [
}
195] . This is designed to monitor plants where quantitative
[
}
196] measurements of dust concentrations are required.
Optical
measuring unit Reflector
Welded-in pipes
with
adjustment flange
Purge air
unit
Universal operation unit
(display and control unit)
Fig. 4.1: System components
●
Protective device (not shown) consisting of:
○
Fail-safe shutter
○
Control electronics
○
Air flow sensor
○
Connecting cable
Principle of operation
The Dust Concentration and Opacity Monitor D‑R 290 operates on the transmission
principle [
}
196] . The measuring head (receiver) and reflector are mounted opposite
each other. Through the use of the auto-collimation principle [
}
195] the measuring
light traverses the measurement path twice and the sensitivity of the measurement is
doubled (see Fig. 4.2 ).
The modulated measuring light transmitted from the measuring head initially traverses
the measuring path as far as the reflector. This reflects it back so that it passes
through the measuring path a second time. The attenuation of the measurement light
beam by the dust particles is thereby proportional to the particle density. The homoge­
neous spot of light on the reflector side has a substantially larger diameter than the
Optional:
4.2.1