4. Thoroughly clean the gasket sealing faces being
careful not to damage the sealing surface. For
reassembly, use new gaskets and place them in
the machined recess of each interior flange on the
two conical sections.
5. Replace the flame element assembly with a new
assembly or properly cleaned and inspected
existing unit.
6. Locate the flame cell assembly such that it seats
onto the gaskets.
7.
Replace all tensioning studs and tighten the outer
nuts hand tight only.
8. Torque the bolts in sequence as shown in the
Torquing Instruction section. Refer to Figure 5 and
Tables 4 and 5.
note
Cleaning of units equipped with a cleaning
system may be accomplished in several
ways including periodic cleaning using
manually operated valves, by use of
an automated cycle timing method
or by having the cleaning operation
initiated whenever the pressure loss
across the arrestor element exceeds a
predetermined value.
inspecting Enardo DFA Element
Assembly Following Flame
Propagation Event
1. Inspect the outboard flame cells for damage
immediately following a deflagration, detonation
and/or stabilized burn.
2. Carefully remove the element assembly from
the arrestor.
3. Inspect the flame cells and the screens visually
for any signs of corrosion or other damage and
inspect the flame cells with a calibrated pin gauge
to ensure maximum crimp size openings do not
exceed the following values for their respective
gas group. Use the following pin gauges as
no-go gauges:
• Model Enardo DFA(E)***/D Explosion
Group D (IIA) – 0.063 in. / 1.6 mm
• Model Enardo DFA(E)***/C Explosion
Group C (IIB3) – 0.039 in. / 1 mm
4. If any damage is noted or crimp openings exceed
maximum size allowable as indicated by the entry
of the no-go gauge, replace the element assembly.
note
Under no circumstance shall any element
assembly not provided by Emerson
be used in this assembly. Failure to
use the correct screens may lead to
arrestor failure.
Element Assembly, Disassembly
and reassembly instructions
WArninG
!
isolate gas supply and bring system
to atmospheric pressure to prevent
ignitable gas from flashing while
performing maintenance.
CAUTiOn
Element assemblies are heavy and
require the use of adequate equipment
and manpower to prevent injury.
note
Element assemblies are provided with
hinges and jacking nuts to facilitate
in-site cleaning of the flame cells or
removal of the element assembly without
the need for removal of the end sections
from the piping system. This method
is intended for use with detonation
arrestors installed in horizontal piping
configurations where adjacent piping is
fully supported such that no loads are
applied to the detonation arrestor.
CAUTiOn
removal and installation of the detonation
arrestor and associated piping require the
use of adequate equipment and manpower
to prevent injury. Detonation arrestors
installed in inclined or vertical orientations
should be entirely removed from the
system for servicing.
8
Enardo DFA Series
Outside North
America Only
