Emerson WORLD CLASS 3000 - Manual (Page 42)

Instruction Manual
Appendix A Rev. 3.6
July 1998
A-8 Appendices Rosemount Analytical Inc. A Division of Emerson Process Management
World Class 3000
Figure A-12. Snubber Diffusion/Dust
Seal Assembly
d. Snubber Diffusion/Dust Seal Assembly
The snubber diffusion/dust seal assembly,
Figure A-12, is used in applications where
an abrasive shield is to be used with a
snubber type diffusion element. The dust
seal consists of two rings of packing to pre-
vent abrasive dust from collecting inside the
abrasive shield.
e. Bypass Probe Options
For processes where the flue gas exceeds
the maximum allowable temperature of
1300°F (704°C) a bypass sensor package
can be employed. The bypass system uses
an 18 inch (457 mm) or 3 foot (0.92 m)
probe mounted externally on the stack or
duct. The process or exhaust gases are di-
rected out to the probe through a passive
sampling system using inconel tubes. Flue
gas flow induces the movement of gases
into, through, and out of the bypass unit.
The bypass arrangement does not require
the use of aspiration air and the gas which
flows past the probe is returned to the stack
or duct.
The bypass probe package is normally used
for process temperatures of 1300°F (704°C)
to 2000°F (1094°C). A higher temperature
version of the bypass provides for operation
at temperatures up to 2500°F (1372°C). In
this version the pick up tubes are made of a
special high-temperature alloy.
Overall dimensions and mounting details of
the American and European bypass sys-
tems are shown in Figure A-13.
f. Probe Mounting Jacket Options
A probe mounting jacket option is available
to allow the probe to operate at tempera-
tures of up to 2000°F (1095°C). A separate
instruction bulletin is available for this
option.