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Invisible and Visible Fire Detection with SBUV

Virtually all types of fires emit photon radiation in the UVC band (240-280nm). Hydrogen, Hydrocarbond, Sulfur, Hydrazine and Amonia emits UV photons such as arc welding, electrical arcs and corona.

Solar Blind UV imaging is the key technology for detection and imaging weak UV emitters during daytime. The core element in solar blind UV imaging devices is a UV Solar Blind optical filter with transmission window in the Solar Blind spectral range (240-280 nm) and high blocking levels out of the transmission band, in the UVb, UVa, visible and near IR spectral ranges. The sun radiation in the 240-280 nm spectral range is totally absorbed by the ozone layer in the atmosphere. Due to this layer, the intensity of the solar radiation reaching the earth at this spectral range is virtually zero allowing a weak UV emitter to be detected or imaged with no disturbing background at high Signal to Noise Ratio (SNR). The bi-spectral SBUVI technology is adaptable for fire and flame detection, even when the emission in the UV solar blind spectral is weak.

Ofil cameras simultaneously detect and display at two different spectral ranges: UV and visible spectrum hence, the accuracy and orientation of the source is exact and pinpointed giving a comprehensive data collection.

The mechanism is simple as illustrated in the block scheme; Ofil's SBUV detect UV photons radiated by the flame, analyze the signal so that no false alarms will be sent. When a real fire is located in the inspected terrain the system set up an alarm in the control center and issue an HTML report with a precise location indicated by the GPS in the system.

As illustrated hereunder, Ofil's cameras can be places on 360° scanning towers with a pan & tilt ruggedized mechanism that fits for harsh weather conditions and has coverage of each camera of 3km radius giving the user a perspective and control of the terrain inspected with extended operation hours and optimal inspection conditions. Moreover, as mentioned above, Ofil's SBUV technology offers a communication protocol, alert and images with GPS locations precise locations can be displayed at a distant control center room.

One of the most common questions is the difference between IR detection and UV detection. When it comes to fire detection the differences are considerably great and important. Since SBUVI detect even the smallest fire (& coals) at great distances it enables the user not only fire detection as the IR technology but also fire extinguish verification. Since the technology's sensitivity is absolute and hence the SBUV is immune to background interferences or weather changes, no false alarm are detected unlike in the IR detection. In addition to the above, SBUV are not sensitive to heat nor hot-spots and its detection and identification is immediate.

There are several of possible applications for this technology:

  • Forest fire detection - a small wooden fire, the size of 100x100x100 cm, is detected by the SBUVI technology from a distance of several kilometers. False alarms like sun reflections can easily be eliminated
  • Alcohol flames (chemical & petroleum industry) - can be detected and located directly with the SBUV technology in early stages of the flame ignition, from distances of hundred meters
  • Protection of Fuel Loading Gantries - such as automatically fuel filling stations and automatic loading Tracks. Ofil has conducted feasibility tests, which indicated the potential of the use of the bi-spectral UV-Visible camera for fire protection in such automatic filling stations
  • Hydrogen fuel - used in launching pads, may leak and will result in invisible flames which can be detected and located with the SBUV system

Ofil's technology for fire detection gives the user a full solution and can be adjusted according to customer requirements starting from optional multi sensors system, with IR and visible cameras, and continuing with LED projectors, pan & tilt mechanism and control & display unit. Ofil's SBUV solution is a powerful, robust and reliable system which can be used in order to maintain safe environment free of fire hazards.

E. Yutcis