Emerson Rosemount Oxymitter DR, Reference Manual

Page: 63 / 98

4.9 Replace ceramic diffusion element
The diffusion element protects the O2 cell from particles in process gases. The element
does not normally need to be replaced, because the vee deflector protects it from
particulate erosion. In severe environments, the filter may be broken or subject to
excessive erosion. Examine the ceramic diffusion element whenever removing the probe
for any purpose and replace it if damaged.
Note
This procedure applies to the ceramic diffusion element only.
Damage to the diffusion element may become apparent during calibration. Compare
probe response with previous response. A broken diffusion element will cause a slower
response to calibration gas.
Prerequisites
To remove set-screws and socket head screws, you will need hex wrenches. These
wrenches are part of a probe disassembly kit (
Table 4 ).
Procedure
1. Follow the instructions given in Remove probe to remove the transmitter from the
stack or duct.
2. Loosen set screws ( Figure 4-4 ) using the hex wrench from the probe disassembly kit
( Table 4 ) and remove vee deflector. Inspect set-screws. If damaged, replace with
stainless steel set-screws coated with anti-seize compound.
3. On systems equipped with abrasive shield, remove dual dust seal gaskets.
4. Use spanner wrenches from the probe disassembly kit (
Table 4 ) to turn hub free
from retainer.
5. Put hub in vise. Break out old ceramic diffusion element with chisel along cement
line and
⅜
-in. (9.5 mm) pin punch through cement port.
6. Break out remaining ceramic diffusion element by tapping lightly around hub with
hammer. Clean grooves with pointed tool if necessary.
7. Replace ceramic diffusion element using the ceramic diffusion element
replacement kit in Table 3 .
This consists of a diffusion element, cement, set-screws, anti-seize compound, and
instructions.
8. Test fit replacement ceramic diffusion element to be sure seat is clean.
9. Thoroughly mix cement and insert tip of squeeze bottle into cement port. Tilt
bottle and squeeze while simultaneously turning ceramic diffusion element into
seat.
CAUTION
Any cement on ceramic diffusion element blocks airflow through the element.
Wiping wet cement off of the ceramic element only forces cement into pores.
Do not get any cement on ceramic diffusion element except where it touches the
hub. Also do not get any cement onto the flame arrestor element.
Reference Manual Maintenance and service
00809-0100-4880 October 2019
Rosemount Oxymitter DR 63