Installation, Operation and Maintenance manual
11
Downflo
®
Evolution
dirty air
inlet
clean air
outlet
cartridge
filter
hopper
NORMAL OPERATION
FILTER CLEANING OPERATION
compressed
air supply
diaphragm
valve
Figure 1: Operational schematic
Protection of the dust collector against dust explosion
The reinforced dust collectors are protected against dust explosions both by preventive
and by constructional measures.
Preventive measures are to prevent ignition sources in the delivered installations:
• Electrical equipment is dust explosion proof: IP6X for zone 20 and IP5X for zone
21 plus equipment surface temperature limitation (depends upon the product).
Gas explosion proof equipment is not necessary but may also be applied when
appropriate.
• If necessary, the filter cartridges are antistatic. (see scope of delivery).
• All conducting parts are grounded or bonded and connected to ground.
• Internal coatings do not cause static hazards etc.
However, these measures do not prevent ignition sources due to the process or
outside influences. Means to eliminate ignition sources from entering the dust
collector are a preseparator, a spark trap or a spark detection with extinguishing
system. Supply of these items are optional and will depend upon the typical process
parameters (see scope of delivery).
So-called constructional or post-operative measures are measures to limit the potential
explosion effects in case an explosion still takes place in spite of the preventive
measures.
The measures taken on the reinforced dust collector are:
• Explosion venting in combination with explosion resistant design for the expected
reduced overpressure and compartimentation
This is a typical mean against the effects of explosions. Of course against fire hazards
alone the dust collector can be delivered with optional sprinkler systems or other
extinguishing systems.
