Det-Tronics U7602B-P Unitized UV Flame Detector/Controller - Manual (Page 9)

POWER CONSUMPTION—
Standby: 1.5 watts, typical.
Fire: 5.0 watts, maximum.
ENCLOSURE MATERIALS—
Models are available in anodized copper-free alu-
minum or 316 stainless steel.
CONDUIT THREAD SIZE—
One or two conduit entries can be provided on each
unit for incoming and outgoing field wiring. Entry
sizes available are: 1/2 inch NPT, 3/4 inch NPT, 20
mm, 25 mm or Pg16.
VIBRATION—
Designed to meet MIL SPEC 810C, method 514.2,
procedure X, curve AW (5 to 200 Hz, 1.5 g).
ENCLOSURE RATINGS—
Watertight, dust-tight NEMA 4 enclosure. FM approved
for Class I, Groups B, C and D; Class II, Groups E, F
and G. CSA certified for Class I, Groups C and D;
Class II, Groups E, F and G. BASEEFA/ CENELEC cer-
tified for EExd IIB T6 (T
amb
–40°C to +75°C) when
ordered with a locking cover assembly. Enclosure
rated IP66. Listed product of the Australian Scientific
Services Laboratory (SSL). VDS (Germany) approved.
DETECTOR SENSITIVITY
The UV flame detector responds to radiation over
wavelengths of 185 to 245 nanometers (1850 to 2450
angstroms). Figure 8 illustrates the range of sensitivi-
ty, and compares this range to other forms of radia-
tion. Note that UV radiation reaching the earth from
the sun does not extend into the sensitivity region of
the detector. In addition, radiation from normal artifi-
cial lighting, such as fluorescent, mercury vapor, and
incandescent lamps does not extend into the detec-
tor's spectral range. As a result, the detector is
insensitive to these forms of radiation and can be
used outdoors or indoors.
NOTE
Some types of high intensity lamps can operate
for extended periods with cracked or otherwise
damaged envelopes, and will then emit UV radia-
tion in the frequency response range of the
detector. Defective mercury vapor lamps should
be immediately removed from service.
The UV sensor responds to any radiation that can
penetrate its glass envelope and create ion pairs. The
glass envelope absorbs most alpha or beta particles,
but it permits both gamma and x-rays to pass through.
If these rays create ion pairs between the electrodes
near the cathode, the normal discharge process will
occur and the detector will produce a count. If the x-
or gamma ray flux is sufficient to produce a count rate
higher than the system sensitivity setting, an unde-
sired response of the system can occur.
Data on sensitivity of the U7602 Detector/Controller to
various x-ray and gamma radiation intensities is
impossible to relate to a typical detector exposure.
The normal precaution against false actuation due to
x-rays or gamma radiation is to turn off the detection
system when sources of high level radiation are being
used in the immediate area. Caution must be exer-
cised if the detection system is turned off, since the
hazardous area will not be protected. If continuous
flame detection is required, contact Detector
Electronics for information on flame detection systems
that can provide continuous flame detection capabili-
ties in these types of applications.
6
5.0 4.0 3.0 2.0 1.5 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1
ATMOSPHERIC
TRANSMISSION
WAVELENGTH (MICRONS)
SOLAR RADIATION REACHING THE EARTH
VISIBLE INFRARED
ULTRAVIOLET SENSOR RESPONSE
ULTRAVIOLET
100
75
50
25
0
A1516
INFRARED SENSOR RESPONSE
Figure 8—Detector Range of Sensitivity
3.24
(82.29)
8.81
(223.85)
4.64
(117.93)
4.99
(126.8)
1.78
(45.09)
1.0
(25.4)
0.5
(12.7)
1.0
(25.4)
0.65
(16.64)
0.281
(7.14)
2.49
(63.37)
1.40
(35.56)
0.34
(8.64)
0.5
(12.7)
MOUNTING KEYHOLES (2)
2.0 (50.8) APART
SEE DETAIL "A"
A1486
1/2 — NPT
3/4 — NPT
20 MM FEMALE
25 MM
PG 16
*
*
DETAIL "A"
Figure 7—U7602 Dimensions in Inches (Millimeters)