Emerson Rosemount 3308A Reference Manual page 33

Reference Manual
00809-0100-4308, Rev CA
Existing chamber
A Rosemount 3308 Series Transmitter is the perfect replacement in an existing displacer chamber.
Proprietary flanges are offered, enabling use of existing chambers to make installation easy.
Figure 3-8. Existing Displacer Chamber
B
A. Replace chamber flange
B. Probe length
C. Displacer Length
Considerations when changing to Rosemount 3308 Series:
The 3308 Series flange choice and probe length must be correctly matched to the chamber. Both
standard ANSI and EN (DIN), as well as proprietary chamber flanges, are available. See
page 146
See Table 3-5 on page 28
See Table 3-3
Table 3-3. Required Probe Length in Chambers
Chamber manufacturer
Major torque-tube manufacture (249B, 249C, 249K, 249N, 259B)
Masoneilan
Other - torque tube
Magnetrol
Others - spring operated
1. If flushing ring is used, add the ring height to the probe length.
2. For other manufacturers, there are small variations. This is an approximate value, actual length should be verified.
3. Lengths vary depending on model, SG and rating, and should be verified.
For additional information, see the Replacing Displacers with Guided Wave Radar
Probe type in chamber considerations
When installing a Rosemount 3308 in a chamber, the single lead probe is recommended. The probe
length determines if a single rigid or single flexible probe should be used:
Less than 19.7 ft. (6.0 m): Rigid single probe is recommended. Use a centering disc for probe > 3.3 ft.
(1 m). When mounting space is limited, use a flexible single probe with a weight and centering disc.
More than 19.7 ft. (6.0 m): Use flexible single probe with a weight and centering disc.
PTFE covered probes are not recommended for chamber/pipe installations.
Installation
PRELIMINARY
A
C
to identify the proprietary flanges.
for guidelines on which disc size to use.
for guidelines on the required probe length.
™
(Torque tube operated), proprietary flange
(2)
® (3)
(spring operated)
(2)
Installation
Table A-19 on
(1)
Probe length
Displacer + 9 in. (229 mm)
Displacer + 8 in. (203 mm)
Displacer + 8 in. (203 mm)
Displacer + between 7.8 in. (195 mm) to 15
in. (383 mm)
Displacer + 19.7 in. (500 mm)
Technical
August 2017
Note.
21