Emerson ROSEMOUNT 3000 - Manual (Page 103)

Instruction Bulletin
Appendix A Rev. 3.9
May 2005
Rosemount Analytical Inc. A Division of Emerson Process Management Appendices A-3
World Class 3000
A-2 PROBE ASSEMBLY EXTERIOR
Primary probe exterior components include a
flange-mounted zirconium oxide cell, mounted
on a tube assembly and protected by a snubber
diffusion assembly.
a. Cell and Flange Assembly
The primary component in the cell and
flange assembly, Figure A-3, is a
yttria-stabilized zirconium oxide cell. It cre-
ates an electrical signal when the oxygen
level on one side is out of balance with the
oxygen level on the other side. This signal
is proportional to the difference in oxygen
levels.
b. Probe Tube Assembly
Four screws secure the cell and flange as-
sembly, Figure A-3, to the probe tube as-
sembly. When in place, the cell is inside the
tube.
The tube assembly includes a flange which
mates with a stack-mounted flange (shown
attached to the probe flange in Figure A-2).
Studs on the stack flange make installation
easy. There is also a tube to carry
calibration gas from the probe junction box
to the process side of the cell during
calibration.
PROBE TUBE
CORRUGATED
SEAL
CELL AND
FLANGE
ASSEMBLY
21240007
Figure A-3. Cell and Tube Assemblies
c. Snubber Diffusion Assembly
The snubber diffusion assembly protects
the cell from heavy particles and isolates
the cell from changes in temperature. The
snubber diffusion assembly threads onto
the cell and flange assembly. Pin spanner
wrenches (probe disassembly kit
3535B42G01) are applied to holes in the
snubber diffusion element hub to remove or
install the snubber diffusion assembly.
An optional ceramic diffusor element and
vee deflector, shown in Figure A-4, is
available. The ceramic diffusor assembly is
also available in a flame arresting version to
keep heat from the cell from igniting flue
gases.
Systems that use an abrasive shield require
a special snubber diffusion assembly with a
hub that is grooved to accept two dust seal
gaskets. This special diffusor is available in
both snubber and ceramic versions. See
Probe Options, section A-6.
DIFFUSION
ELEMENT
VEE
DEFLECTOR
PIN
WRENCH
HUB
21240024
Figure A-4. Optional Ceramic Diffusor and Vee
Deflector Assembly