flame detection design: a balancing act
DESCRIPTION
Detection Capability Range Fuel. Interference Rejection Resistance level Impact on Flame Detection. Flame Detection Design: A Balancing Act. Flame Detection. Solar radiation. Wavelength (microns). Typical interference. UV detectors. Ultraviolet Sensor Operating Principle. - PowerPoint PPT PresentationTRANSCRIPT
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Flame Detection Design: A Balancing Act
DetectionCapability
• Range • Fuel
InterferenceRejection
• Resistance level• Impact on Flame
Detection
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Flame Detection
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Solar radiation
Wavelength (microns)
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Typical interference
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UV detectors
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Ultraviolet Sensor Operating Principle
• Solar blind 1850 to 2450 • UV photons strike tube cathode• Cathode releases electron• Electron strikes gas molecule• Cascade effect occurs to anode• Discharge is quenched, creates pulse
(count) output• Pulse output measured in CPS
(counts per second)
Anode
CathodeOi Test Source
Plastic housing
connectors (a,b,c,d)
Quartz Envelope
Det-Tronics UV Sensor
circuit board
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• Enhanced Arc Rejection• Faster and more false alarm
resistant
Ultraviolet Flame Detector
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IR detectors
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IR Sensor Operating Principle
• Optical filter mounted to sensor• 4.45 micron band-pass• Flicker modulation required• Steady state IR sources ignored
Optical Bandpass
Filter
Pyroelectric Infrared Sensor
Infrared Energy
Flicker Filter
Circuitry
Output Circuitry
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• Analyzes the raw IR sensor signal “randomness”• Rejects signals that do not meet randomness criteria
No Fire Alarm
Fire Alarm!
TDSA
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Single Frequency Infrared Flame Detector
• TDSA IR signal processing• Quick fire response• Heated optic
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UV/IR detectors
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• ARC UV and TDSA IR signal processing• High Speed• Heated IR optic sensor
Ultraviolet Infrared Flame Detector
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Ultraviolet Infrared Signal Processing
• Dual Spectral Processing– Arc rejection UV sensor– TDSA IR sensor
• UV sensor (and gated) with the IR sensor• Alarm only when processing time is met by both sensors
simultaneously
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Multi-spectrum IR detector
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Spectral Analysis
• Determine unique spectral features of sources
• Use multiple Infrared bandwidths to optimize desired
capabilities
• Develop algorithms to identify signatures
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Typical signal/reference band multi IR
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• Patents– Wavelength– Algorithm– Digital signal Processing
• Extended Cone of Vision
X33AF Multispectrum Infrared Flame Detector
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X33AF IR3X33AF Multi-spectrum63m‘
UV/IR
UV/IR 30m
SFIR
SFIR 25m
COV Test data for 1’ * 1’ gasoline fire