Installation, Operation and Maintenance manual
6
Downflo
®
Evolution
Gas explosion proof equipment is not necessary but may be used when
appropriate.
Maintenance and explosion safety
a. Introduction
The collection systems are designed and installed by Donaldson Torit engineers
applying the most appropriate safety measures based upon state of the art knowledge
and technology.
It’s safety is based upon two main objectives:
• Prevent ignition sources that might be caused by the collection system itself, as
far as it is practically possible, by using appropriate dust explosion proof electrical
equipment, antistatic filter cartridges, conductive construction materials and ducts
which are all bonded and grounded.
• Confine an actual explosion caused by an ignition source coming from the
process or induced by the user (hot work collection system) in such a way that
no hazardous effects occur:
• to plant personnel
• to the location in which the dust collector is installed
• to equipment connected to the dust collector
If the dust collector’s original design or the actual process is changed without
implementing the changes in the safety design of the collection system, it’s
safety can be jeopardised. However, poor and/or incorrect maintenance can
also jeopardise the safety of the system.
b. Hazards due to change of dust collector design
The housing is modified; a larger volume, weaker housing (e.g. by installing
extra inlets or manholes).
The vent area is reduced; e.g. by obstructing the vent by ducts or other
obstacles.
The vent panel type is changed; e.g. by using a panel that has a higher opening
pressure or larger inertia.
The vent duct is modified; longer, smaller cross section, bends, obstacles or
extra covering on the outlet.
The vent location is altered; e.g. instead of top venting now side venting is
applied - besides possibly obstructing the vent process, reaction forces may
cause the collector to tumble over.
If applicable, the explosion suppression system is modified.
In these cases the safety measures may not be able to protect sufficiently and
the explosion may destroy the housing and or the vent duct causing hazards
around the dust collector. In particular when the dust collector is located inside
the hazards are eminent.
The rotary valve is taken out or exchanged by a non explosion proof type. Or
the explosion resistant receiver bin is exchanged by a non appropriate type.
This may lead to flames, or worse, a fireball emerging from the hopper.
