Emerson Process Management OXYMITTER 4000 - Manual (Page 134)

Instruction Manual
IB-106-340C Rev. 4.1
July 2004
9-16 Maintenance and Service Rosemount Analytical Inc. A Division of Emerson Process Management
Hazardous Area Oxymitter 4000
27540008
PORT
CEMENT
THREADED
PROBE FLANGE
SPANNER
WRENCH
M5-0.8 x 5 mm
LOCKING SET SCREW
(USE 2.5 mm HEX KEY)
CERAMIC
DIFFUSION
ELEMENT
M6-1 x 6 mm
SETSCREW
(USE 3 mm
HEX KEY)
CEMENT
FILLET
VEE
DEFLECTOR
FLAME
ARRESTER
HUB
Figure 9-10. Ceramic Diffuser Element
Replacement
3. Remove the locking set screw from the
flame arrestor. Use spanner wrenches
from the probe disassembly kit (Table
11-1) to turn the flame arrestor hub
free from the probe flange. If equipped
with the flame arrestor with ceramic
diffuser, remove and discard the
setscrews and remove the vee deflec-
tor (Figure 9-10). Inspect the ceramic
diffuser. If damaged, replace using
paragraph 9-4i.
4. Loosen the four socket head cap
screws from the cell and flange as-
sembly. Remove the assembly and the
corrugated seal. The cell flange has a
notch that may be used to gently pry
the flange away from the probe. Note
that the contact pad inside of the probe
will sometimes fuse to the oxygen
sensing cell. If the cell is fused to the
contact pad, push the cell assembly
back into the probe (against spring
pressure) and quickly twist the cell as-
sembly. The cell and contact pad
should separate. If the contact pad
stays fused to the cell, a new con-
tact/thermocouple assembly must be
installed. Disconnect the orange cell
wire at the probe electronics end of the
strut by cutting the wire. Withdraw the
cell with the wire still attached.
5. Remove entire electronics per para-
graph 9-4b, steps 2 and 3.
6. If the contact and thermocouple
assembly is damaged, replace the
assembly or the contact pad. Refer to
paragraph 9-4j to replace the contact
and thermocouple assembly. Instruc-
tions for replacing the contact pad are
in the cell replacement kit.
7. Remove and discard the corrugated
seal. Clean the mating faces of the
probe tube and cell. Remove burrs and
raised surfaces with a block of wood
and crocus cloth. Clean the threads on
the probe flange and flame arrestor
hub.
8. Apply a light coating of anti-seize
compound to both sides of the new
corrugated seal.
9. Assemble the cell and flange assembly
and corrugated seal to the probe tube.
Make sure the calibration tube lines up
with the calibration gas passage in
each component. Apply a small
amount of anti-seize compound to the
screw threads and use the screws to
secure the assembly. Torque to 4 N·m
(35 in-lbs).
10. Apply anti-seize compound to the
probe threads, flame arrestor hub, and
setscrews. Reinstall the flame arrestor
on the probe. Using pin spanner
wrenches, torque to 14 N·m (10 ft-lbs).
Secure the flame arrestor with the
locking setscrew. Torque to 2.8 N·m
(25 in-lbs). If applicable, reinstall the
vee deflector, orienting apex toward
gas flow. Secure with the setscrew and
anti-seize compound. Torque to 2.8
N·m (25 in-lbs).
11. On systems equipped with an abrasive
shield, install the dust seal gaskets,
with joints 180° apart.