Flame Detection Design: A Balancing Act

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Flame Detection Design A Balancing Act

• Detection
• Capability
• Range
• Fuel

• Interference
• Rejection
• 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)

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Ultraviolet Flame Detector

• Enhanced Arc Rejection
• Faster and more false alarm resistant

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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

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TDSA

• Analyzes the raw IR sensor signal randomness
• Rejects signals that do not meet randomness
  criteria

No Fire Alarm
Fire Alarm!
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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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Ultraviolet Infrared Flame Detector

• ARC UV and TDSA IR signal processing
• High Speed
• Heated IR optic sensor

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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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X33AF Multispectrum Infrared Flame Detector

• Patents
• Wavelength
• Algorithm
• Digital signal Processing
• Extended Cone of Vision

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COV Test data for 1 1 gasoline fire