Flame Detection Theory

8/13/2019 Flame Detection Theory

1/26

E VERY L IFE H A S A P URPOSE

Flameetection

Theory


2/26

Requirements of a Fire

Oxygen


3/26

Characteristics of a Fire

High Emissions of Ultraviolet Radiation

High Emissions of Infrared Radiation

Presence of Light, Smoke and Airborne Debris


4/26

False Alarm Sources

Arc Welding

Sunlight

Infrared Energy

Modulation

Reflective


5/26

Characteristics of a Fire

Ultraviolet Region Visible Region Infrared Region

Suns radiationreaching the Earth

RelativeEnergy

4 0 0 n m

2 t o 3

m i c r o n s

Wavelength


6/26

UV Phototube

4 0 0 n m

2 t o 3

m i c r o n s



RelativeEnergy


7/26

UV PhototubeUltravioletRadiation

Photocathode

Electrons

Anode

-VDC

+

Gas-FilledPhototube


8/26

IR Devices

4 0 0 n m

2 t o 3

m i c r o n s

Wavelength



Relative Energy


9/26

IR Devices

4 0 0 n m

2 . 7

t o 3

. 2

m i c r o n s

Wavelength



Hydrogen firesemit H 2O vapors@ 2.95 microns

RelativeEnergy


10/26

FlameGard 5 UV/IR

FlameGard 5 UV/IR

Ultraviolet + Infrared DetectionPhoto-tube + Pyroelectric (Flicker)


11/26

FlameGard 5 UV/IR Features

Monitors in both UV and IR spectral rangesreducing possibility of false alarms caused bylightning, arc welding, hot objects etc.Typical Response time: < 3 seconds @ 50ft120 maximum horizontal field of view-40F to +185F (-40C to +85C) operatingtemperatureCOPM (Continuous Optical Path Monitoring)RS-485 Modbus RTU, HARTHydrogen fire configuration available


12/26

FlameGard 5 UV/IRPhysical Characteristics

AssemblyThree Distinct Explosion-proof Housings:

UV/IR

COPM Light Rods (Reflective Coated)UV - StraightIR - Curved

O-Ring Sealed Windows

Common Base with Bracket Mounting Holes Two (2) Bottom Entry Conduit Connections (3/4 NPT) Drip Lip (3/4 of housing mating surface)


13/26

FlameGard 5 UV/IR Specifications

EnvironmentalTemperature

FlameGard 5 UV/IR -40C to 85C (-40F to 185F)

RatingsIP 66, Type 4X, Class I, Div 1, Groups B, C & D;Class II, Groups E, F & G; Class III


14/26


PerformanceImproved detection and false alarm immunity

Field-of-ViewFlameGard 5 UV/IR - 115 Vertical, 120 Horizontal

Optical Sensitivity1 sq. ft. fire at 50 ft.


15/26

FlameGard 5 UV/IR Field of View(Horizontal)

15

HORIZONTAL

SENSITIVITY

HORIZONTAL(5)

0

50%75%

100%

60

30

45

15

60

45

10'

15'

40'

35'

30'

25'

20'

30

15 50'45'

0

25'50'50'

50'

50'

30'


16/26

FlameGard 5 UV/IR Field of View(Vertical)

-45

-30

-15

-60

0 5

0 '

+15

4 0 '

4 5 '

3 5 '

+30

+45

2 5 '

3 0 '

2 0 '

1 0 '

1 5 '

+60

VERTICAL

TABLE CHART100%

75%

50%

(5)

SENSITIVITY

60 20'

VERTICAL

45

30

15

0

50'

50'

50'

50'

100%


17/26


Performance

Spectral SensitivityFlameGard 5 UV/IR: 185 to 260 nanometers & 4.35 microns

Response Time (Normal Operation

FlameGard 5 UV/IR

Detector Response (nominal) < 500ms

Output Response (50 ft. fire) < 3sec.


18/26


Outputs4-20 mA Signal

0 mA, Fault 2 mA, COPM Fault 4 mA, Ready 8 mA, IR Only 12 mA, UV Only 16 mA, Warn

20 mA, Alarm (After time delay)


19/26


OutputsCommands

Read Only4-20 mA

Alarm, Warning, FaultUV Only Signal, IR Only SignalUV Source Lamp Fault, IR Source Lamp FaultLow VoltageCommunication Faults

Write Only Auto Test, Reset, Accept

Read and Write Address, Modbus SetupSensitivity (100%, 75%, 50%)Time Delay, Relay States


20/26


OutputsRelays: (3) SPDT (8-amp, 24 VDC/250 VAC

Resistive)

Warning (Immediate, no time delay)

Alarm (After 2, 4, 8 or 10 Sec. Time Delay)

Dip Switch Selectable

RS-485 Selectable (Non-intrusive over-ride)

Fault (Energized, non-latching )


21/26


SystemModes:

NormalSelf Test (Power-up)

Alarm Test (Remote)

Fault Diagnostic -Status Indication (LED)

Other Fault Diagnostics via RS-485

RED LED GREEN LED CONDITION

ALTERNATING TIME OUT 10 SECONDS AFTER START-UP

OFF 10 SEC. BLINK READY NO FLAME RADIATION PRESENT

SLOW BLINK ON WARN FLAME RADIATION PRESENT

FAST BLINK ON ALARM WARN +TIME DELAY

OFF SLOW BLINK FAULT COPM FAULT DETECTED

OFF FAST BLINK FAULT LOW VOLTAGE CONDITION


22/26


Approvals

CSA, FM, ATEX, CE Marking

Power20-36 VDC Nominal @ 150 mA Max.

Input Terminals

Test and Reset

Wiring: 12 AWG to 22 AWG


23/26

FlameGard 5 Test Lamp

Rechargeable/replaceablebatteriesEasy grip handle integralwith housing

Spring return on/offswitch to conservebattery lifeExplosion-proof castaluminum housingCSA ApprovedATEX Approved


24/26

Key Features / Benefits

Excellent Discrimination of False Alarms UV detection in the 185-260 nanometer range whichis well below natural sunlight and artificial light.

IR detection at 4.3 microns which is the CO 2 spikegenerated from hydrocarbon fires.

Flicker discrimination algorithm, which eliminatesfalse alarms from IR sources.

Arc welding and lightning will not cause theFlameGard UV/IR to go to false alarm.


25/26


COPM Continuous Optical Path Monitoring We check the optical path once every minute on boththe UV and IR sides to make sure the windows arenot dirty, and that the test sources and detectors areworking properly.

Wide Angle of View 120 angle of view is the widest in the industry whichallows for a larger area of coverage and a reducednumber of detectors.


26/26


Hydrogen Fire Specific Flame Detector Uses a wavelength of 2.7-3.2 microns onthe IR detector to detect the water spike ofHydrogen fires.

Output Capability Three programmable relays (8 AMP)0-20 mA stepped output to allow quickdiagnostics for UV only, IR only, COPMFault and overall FailuresModbus for digital communicationHART------Digital Communication protocol.Communicates via analog output line.

Flame Detection Theory

Documents

Transcript of Flame Detection Theory