Notifier 30-2021E-24 - Manual

DN-1253:B • 8/25/2010 — Page 1 of 4
30-2021-24 &
30-2021E-24
Ultraviolet Flame Detectors
Conventional Initiating Devices
DN-1253:B • I-207
General
The Pyrotector Model 30-2021-24 and Model 30-2021E-24
Ultraviolet (UV) Flame Detectors are highly sensitive to the
ultraviolet radiation given off by all types of flames, including
those produced by flammable liquids and gases. Since the
detector does not respond to normal ambient light conditions
such as sunlight, incandescent or fluorescent lighting, it is ide-
ally suited for use as a flame detector in a variety of areas.
The Pyrotector Ultraviolet Flame Detector is a compact unit-
ized package consisting of a detection tube, encapsulated
solid state electronic circuitry, and a dry-contact Form-C
(SPDT) alarm relay. In the event of an alarm, the relay latches
on and an alarm light is illuminated for easy identification of
the unit in the alarm state. The relay is reset by momentarily
interrupting power to the unit. A three-second time delay is
built in to minimize false alarms cause by the presence of
sparks, lightning, etc.
• Model
30-2021-24 is contained in a general purpose enclo-
sure and is intended for indoor use only. It mounts on a
standard 4" (10.16 cm) octagonal electrical junction box
(not included).
• Model 30-2021E-24 is intended for indoor use and is con-
tained in an explosion-proof enclosure that meets all
requirements for NEC Class I Groups C and D; Class II
Groups E, F, and G; and Class III hazardous locations.
• Both models operate on 24 VDC.
Theory Of Operation
The Model 30-2021-24 and Model 30-2021E-24 UV Flame
Detectors operate with a Geiger-Muller-type tube that utilizes
an ultraviolet sensitive photocathode within a fused silica enve-
lope. When exposed to UV radiation, the photocathode emits
electrons that ionize the inert gas inside the tube. This initiates
the current flow that produces an alarm signal.
Application Considerations
To ensure proper operation of the detector, the viewing window
and the surface of the sensing tube must be kept clean and
free of contaminating films at all times. When cleaning the
sensing tube, the user must exercise caution to apply mini-
mum pressure, thereby minimizing the possibility of damage to
the detector tube.
Cutting and welding operations within the cone of vision of the
detector can generate high levels of UV radiation that can
result in actuation of the detection system. To avoid unwanted
alarms, it is suggested that the detection system be de-ener-
gized while these activities are occurring.
It should be noted that ultraviolet detectors will not detect glow-
ing embers
. A high-speed ember detector such as the Model
30-2054-24 or 30-2054A-24 should be used for this type of
application.
Specifications
• Operating voltage: 22 to 27 VDC for 24 VDC unit.
• Operating current: STANDBY: 12 mA maximum @ 24
VDC. ALARM: 100 mA@ 24 VDC.
• Alarm relay contact rating: 1 A @ 26 VDC.
• Spectral sensitivity range: 1700 to 2900 angstroms, with
peak response at 2100 angstroms.
• Temperature range: –13°F (–25°C) to +140°F (+65°C).
• Humidity range: up to 90% RH.
PHYSICAL SPECIFICATIONS, 30-2021-24:
• Enclosure type: general-purpose painted steel with pro-
tective cage and totally encapsulated electronics.
• Dimensions: 4.09" (10.389 cm) diameter; 3" (7.62 cm)
deep.
• Weight: 0.75 lb. (0.34 kg).
PHYSICAL SPECIFICATIONS, 30-2021E-24:
• Enclosure type: explosion-proof housing with 3/4" (1.905
cm) NPT female entries. NEC Class I, Groups C and D;
Class II, Groups E, F, and G; Class III.
• Dimensions: 6.76" (17.17 cm) x 2.75" (6.985 cm) x 4.75"
(12.065 cm).
• Weight: 3.75 lbs. (1.7 kg).
Detector Sensitivity
The response time of the detector is a function of the size of
the fire, fuel type, and the distance from the detector to the fire.
Smaller fires and greater distances normally require greater
response times. Figure 1 illustrates the relative sensitivity of
the Model 30-2021-24 Detector to gasoline fires. Figure 2
shows the relative sensitivity of the Model 30-2021E-24.
The Model 30-2021E-24 is approximately 10% less sensitive.
For example, a three-second response time is achieved at 10
feet (3.048 m) rather than 12 feet (3.658 m) when detecting a
6" (15.24 cm) gasoline fire.
Model 30-2021-24
30-2021.tif
30-2021e.tif
Model 30-2021E-24