FIRE IR SENSOR Flame Detection

Transcription

1 FIRE IR SENSOR Flame Detection

2 Introduction Detects Open Flames Sensitive to Flickering IR or UV/IR Emissions from Flames Low Power 24Vdc Operation, 4-20mA or Relay Interface

3 Why use Flame Detectors? Heat & smoke detection are the most economical method But if detection is required to be: Unaffected by convection currents, draughts or wind IR sensors are tolerant of fumes, vapour, steam, dust and mist Detection at over 25m away Fast reaction

4 Applications Aircraft hangars Automotive industry Coal handling plant Pharmaceuticals - fume cupboards Paper manufacture Power plants Textiles Waste handling Woodworking

5 Applications to Avoid Ambient temperatures above 55 C Where the detector may view - Flickering or moving hot objects (>200 C) Sunlight falling directly onto IR optics Flood or spot lights directly on optics Large amounts of flickering reflections Exposure to severe weather Close proximity to RF sources

6 Theory of Operation Detector Optics IR2 Detector Optics A B Signal Processing Input/Output Interface

7 Optical Spectra Intensity UV Visible Near IR Wavelength -µm

8 Intensity Detector Optics IR Detectors A B 6000K Black body, Sun Hydrocarbon Flame UV Visible Near IR Mid. IR Other Types 4.3µm A B 4.3 Wavelength -µm Excluding Atmospheric Absorption

9 Highest Immunity to False Sources Low Types of Detectors UV Visible Near IR Mid IR 0.4µm 0.75µm 3.0µm Optical Spectrum Detection Methods Triple IR UV/IR Dual IR (IR²) 4.3 µm Single IR UV

10 Flame Detector Selection Detector Types Single IR Low Immunity to false sources - Lowest Cost - Fastest Response Time (For Enclosed & Dark Areas) Dual IR (IR²) High Immunity to false sources (Indoor Areas) Triple IR (IR³) Excellent Immunity to false sources (Indoor or Outdoor Areas) UV/IR² Highest Immunity to false sources (Indoor or Outdoor Areas) Applications Applications Applications Applications Agriculture Bed Fillings Coal Milling Dryers Dust Collection/Filters Felt Manufacture Wallpaper Production Woodworking Churches Coal Handling Fume Cupboards Printing Spray Booths Textiles Waste Handling Atria Coal Handling Nuclear Industry Pharmaceuticals Printing Spray Booths Storage Tanks Tunnels Waste Tips Aircraft Hangars Engine Rooms Engine Test Facilities Generators High Voltage Equipment Nuclear Industry Power Plants Storage Tanks

11 Theory of Operation Detector Optics Signal Processing IR2 Detector Optics A B Signal Processing Input/Output Interface

12 Flicker Signal - % Signal Processing Flame Flicker Frequency Spectra Hz

13 Flicker Signal - % Typical Flame Flicker Typical Flame Hz

14 Flicker Signal - % Energetic Flame Flicker Energetic Flame Typical Flame Hz

15 Theory of Operation Detector Optics Signal Processing Input/Output Interface IR2 Detector Optics A B Signal Processing Input/Output Interface

16 Output Interface Option 4-20mA P roportional Output (Non-latching) ma Time (Seconds) Typical Response on seeing Flame

17 Output Interface Option 4-20mA P roportional Output (Non-latching) ma Time (Seconds) Typical Response after last Flame is seen.

18 Output Interface Option 4-20mA P roportional Output (Non-latching) ma Time (Seconds) Typical Response to a Burst of Flame

19 Output Interface Option 8-20mA Latching Output ma Time (Seconds) Typical Response on seeing Flame - Break supply to reset

20 Detector Performance Class 1 performance as defined in EN54:Part 10 Flame detectors point detectors Yellow flickering flame of approximately 0.1m² or clear flame of 0.25m² at 25m

21 Detector Performance 0.1m² flicking yellow flame at 25m 0.1m² 0.4m² flicking yellow flame at 40m 0.4m²

22 Selection of Fires Tested Solids Liquids Gases Coal Cotton Grain & Feeds Paper Refuse Wood Or just Dust from the above Aviation Fuels Ethanol Methylated Spirits n-heptane Paraffin Petrol Butane Fluorine Hydrogen Natural Gas Off Gas Propane

23 Detector Field of View IR SENSOR FIRE 90 Cone

24 Detector Field of View m 40m 90

25 Calculation of Detection Distance IR SENSOR FIRE = L² + W ² + H ² Height Width Length 20² ² ² example 22.9m =