I.R.I.S. FLAME MONITORING SYSTEM P522 - Manual (Page 13)

IRIS MODEL P522 APPLICATION MANUAL
Page 13
detected). The 4-20mA output will still perform the
same way on the high end (i.e., on a strong signal, it
will saturate at the same level, slightly above 22mA).
Specifications for the analog current output signal
are provided in SPECIFICATIONS Figure 13.
INSTALLATION OF VIEWING HEAD
Before beginning the actual installation, determine
the best location for mounting the viewing head based
upon the following factors:
PRESSURE
The viewing head lens will withstand 5 psi. If the
lens assembly is exposed to greater than 5 psi through
sight pipe, then an isolation unit must be used. An
IRIS isolation unit with purge air entrance is avail-
able as an accessory.
TEMPERATURE
The viewing head will withstand an ambient tem-
perature to 80°C (176°F). However, the case tem-
perature of the housing must not exceed 60°C
(140°F). Purge air will help reduce conducted heat
through sight pipe to flange (a plastic nipple will also
help), but direct radiation can cause housing case
temperature to exceed limits. If the ambient heat
(direct radiation) is excessive, then a fiber optic ex-
tension should be used (please refer to the IRIS
Model 500 Fiber Optic System manual). This sys-
tem is composed of a viewing head, a fiber optic
assembly, and an amplifier module.
The model S5xx series of viewing heads have in
place a sensor for sensing the internal temperature
of the head. To access the reading of the viewing
head temperature, press the “Reset” and the “Down”
arrow key at the same time. The temperature read-
ing will be displayed in the four-digit readout. The
reading (indicated in °C) will disappear and the nor-
mal reading will continue after several seconds.
VIBRATION
Do not install the viewing head where it could be
subject to vibration. A vibrating viewing head
(flicker type) can simulate flame when viewing a
glowing background. Provide an antivibration mount
if excessive vibrations are present.
CLEARANCE
Make sure there will be sufficient room to remove
the housing for servicing (see Figure 16).
SIGHTING OF THE VIEWING HEAD
In general, the sighting of the viewing head should
be parallel to the center line of the burner in the di-
rection of the burner flame. This applies to both the
UV type as well as the flicker type. Flicker type
detectors respond to the high frequency flicker of
the flame; so, in order to achieve maximum dis-
crimination between burners, the near portion of the
primary combustion zone should be favoured –
meaning the sight pipe should be mounted as close
as possible to the burner center line. The sight pipe
should be aimed at the root of the flame, which radi-
ates the most intense, high-frequency flicker energy.
Sighting along the flame rather than across it per-
mits the detector to view a greater depth of the flame
root, obtaining better response (see Figure 17).
When sighting for a UV viewing head, you must aim
for the UV zone, which is usually at the very first
part of the flame root. UV radiation from most flames
is restricted to a narrow region: it starts very close
to the burner nozzle and does not extend out very far
from the burner nozzle. You may have to angle the
sighting inward toward the flame root, as shown in
Figure 18.
R E B M U N D L O R E B M U N W E N
6 0 5 S 6 0 5 S
S 2 X R I 9 0 5 S
S G R I 1 1 5 S
S R I 2 1 5 S
FIGURE 7 - VEWING HEAD CROSS-
REFERENCE TABLE
VIEWING HEAD CROSS-REFERENCE