DN-1253 • 10/29/04 — Page 1 of 4
7210-1208:102
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 ambi-
ent light conditions such as sunlight, incandescent or fluorescent light-
ing, it is ideally suited for use as a flame detector in a variety of areas.
The Pyrotector Ultraviolet Flame Detector is a compact unitized pack-
age 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 momen-
tarily 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 enclosure 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 contained 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 uti-
lizes an ultraviolet sensitive photocathode within a fused
silica envelope. When exposed to UV radiation, the photo-
cathode 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 contaminat-
ing films at all times. When cleaning the sensing tube, the user must
exercise caution to apply minimum pressure, thereby minimizing the pos-
sibility 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-energized while these activities are occurring.
It should be noted that ultraviolet detectors will not detect glowing
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:
Model 30-2021E
Model
30-2021-24
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 protective cage and totally en-
capsulated electronics.
• Dimensions: 4.09" (10.389 cm) diameter;
3" (7.62 cm) deep.
• Weight: 0.75 lb. (0.34 kg).
30-2021-24
and
30-2021E-24
Ultraviolet Flame Detectors
October 29, 2004
DN-1253 • I-207
Section: Conventional Initiating Devices
California
State Fire
Marshal
Pyrotector is a brand name of Detector Electronics Corporation.
This document is not intended to be used for installation purposes. We try to keep our
product information up-to-date and accurate. We cannot cover all specific applications or
anticipate all requirements. All specifications are subject to change without notice.
For more information, contact NOTIFIER. Phone: (203) 484-7161 FAX: (203) 484-7118
12 Clintonville Road, Northford, Connecticut 06472
NOTIFIER® is a Honeywell company.
