BFI Automation 2.0L, Original Operating Instructions

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Description
5-1
5 Description
5.1 Functional description
The flame scanner 2.0L operates on the basis of the
spectral analysis method of the UV-VIS and IR flame ra-
diation analysis. The flame radiation will be coupled via
the lens of the SKL-probe into the fibre optic cable and
transfered to the semi conductor sensor. Both spectral
ranges are converted separately by a dual detector and
are analysed selectively with an automatic pre-amplifier
and integrated frequency controller.
The high-frequency flame modulation of the primary com-
bustion zone is utilised in an ideal manner in this way.
Cancellation of the UV-VIS flicker frequencies cannot oc-
cur again as the high-energy IR radiation is processed
separately. The usually undesired continuous-light part of
the flame is used for the fuel-specific control of the flame
scanner. A dual detector consists of a lead sulfide carrier,
to which a silicon photo element has been deposited by
evaporation. The Si element thus acts as an UV filter in
front of the PbS elements, which is located on the same
axis. Thus, the short-wave radiation part is blocked out
which otherwise could lead to problems in the use of PbS
detectors. The compensation controlled by the ambient
temperature stabilizes the operation point of the flame
scanner and maintain the spectral linearity. The signals of
both photo-elements results in an aggregate signal of a
every large spectral bandwidth in the mixed stage. Among
other things, the spectral shift of the flame renders infor-
mation on the oxidation of the fuel and thus on the quality
of combustion.
The signal parts of the UV-VIS and IR radiation intensities
can be set separately in order to exhaust the potentialities
of flame analysis to the full. The downstream bandpass
ensures that the typical flame radiation modulation of the
primary combustion zone only is used for the output sig-
nal. The other functional groups are used for conversion
into standardized digital information in the biggest possi-
ble interference safety.