grafik exschutz 102016 eng - keller lufttechnik · 2019-02-06 · selection of explosion protection...
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Selection of explosionprotection measures fordust extracting system
Is the dustexplosive?
Separation of metal dust?
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YES
NOExamples: mineral dust, ceramic dust, normally stainless steel, welding fume
No additional measures necessary
Examples: organic dust,light metal dust, steel dust
Can an explosive environment be avoided?
Evaluation criteria(Responsibility with operator)
Operator’s safety data sheet required
Evaluation by means of GESTIS dust-ex data base
Dust examination by KL/testing institute
Dosing unit with weight monitoring
Detection of mixing ratio
Wet separation (only with exhaust air operation)
Solid inertisation (small amount of dust)
YESNo additional measures necessary
TO SOME EXTENT
(Dry separator)
NOAvoidance of ignition sources within the extraction system
MIE > 10 mJ (normal ignition energy) – and can the collection of effective ignition sources be excluded?
YES No additional measures necessary
Potential equalization ductwork
Potential equalization filter system
ATEX componentsPackage "Ignition source avoidance"
Outdoor installation
Installation at an outside wall
NO
NO
Horizontal pressure relief by burst panels
Safety zone approx. 10 - 20 m
Reduced safety zone (approx. 2.5 - 3.5 m)Vertical pressure relief (deflection by burst panels)
YES
Horizontal pressure relief by burst panels + safe keeping
Angular pressure relief by burst panels + Targo-Vent + safe-keeping
Safety zone approx. 10 - 20 m
Reduced safety zone (approx. 7 - 14 m)YES
NO
For processes with a small amount of dust and rare ignition sources
Cleaning during downtimeProSens protection concept
Monitoring for access by ignition sources
ProVentPlus (with TR-1)
ProPipe
ProPipePlus
ProSens (see above)Pressure shock resistance normally 10 bar
Safety zoneFlameless pressure relief for aluminum dust at KST = 300
No safety zone
Flameless pressure relief for aluminum dust at KST = 180
No safety zone
Flameless pressure relief for aluminum dust at KST = 180
Design on Pmax
YES
Explosion suppression
Flameless pressure relief ProVent
No safety zonePressure shock resistance normally 0.4 barWith toxic dusts, gases/hybrid mixtures
Pressure shock resistance normally 0.4 bar
Safety zoneNO
Selection of fire protection measures with air pollution control systems
Internal ignition sources within system
External ignition sources
Examples:- Hot surfaces- Static electricity
Can be eliminated with protective measures
Ignition sources in the event of a fault
Protection version A no ignition sources under normal operating conditions
No mechanical fire-prevention measures
Examples:- Mechanically created sparks e. g. grinding processes- Flames and hot gases e. g. thermal spraying, welding- Hot particles e. g. glowing sparks from machine tool
Protection version BMeasures to prevent fires
Protection version CMeasures for damage control
Ignition sources under normal operating conditions
Spark pre-separatoin
Spark detection and extinguishing
Solid matter inertization
Cyclone separator Separation of ignition sources and particles
Separation of coarse particles
Energy extraction through contact with baffle plates, not suitable for larger volumes of dust
Impact separator
Cascade separatorNon-cumbustible dust(BZ = 1)
Combustible dust(BZ > 1) Fire detection
Manual fire fightingSimple extinghuisher opening Extinguishing by third parties
Semi-stationary extinguishing system - not all components built in- effective only after applying extinguishing agent
Stationary extinguishing system- all components built in- detection, signaling, extinguishing fires in the earliest stages
ABC powder extinguishing
Fire department
Manual extinguishing agents:- Argon- D-Powder- ABC-Powder
Automatic extinguishing - Extinguishing system
water extinguishing
Fire hazard due to:- Filter elements- Secondary material, e. g. oil-bearing air- Dust
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Protection version BMeasures see mentioned above
Examples:- Mechanically created sparks e. g. malfunction in machine tools- Exothermal reactions, including spontaneous combustion of dusts e. g. accumulation of dust in Big-Bag