Vessel Characteristics; 10Disturbing Objects; 11Valves - Emerson Rosemount 5400 Series Reference Manual

Reference Manual
00809-0100-4026, Rev HA
3.3.9

Vessel characteristics

Heating coils, agitators and other objects in the tank may lead to disturbing echoes and noise in
the measurement signal. Vertical structures cause minimal effect since the radar signal is
scattered rather than directed back to the antenna.
The shape of the tank bottom affects the measurement signal when the product surface is close
to the tank bottom. The Rosemount 5400 Series has built-in functions which optimize
measurement performance for various bottom shapes (see
on page
3.3.10 Disturbing objects
The Rosemount 5400 Series transmitter should be mounted so that objects such as heating
coils, ladders, etc. are not in the radar signal path. These objects may cause false echoes
resulting in reduced measurement performance. However, the transmitter has built-in functions
designed to reduce the influence from disturbing objects where such objects cannot be totally
avoided.
The Rosemount 5402 has a narrower radar beam that is particularly suitable in installations with
tall or narrow nozzles, or nozzles close to the tank wall. It may also be used to avoid disturbing
objects in the tank.
3.3.11 Valves
The Rosemount 5400 Series transmitter can be isolated from the process by using a valve:
„
„
„
Valves can be combined with stilling wells.
Mechanical Installation
76).
Use a full-port ball valve.
The 5402 is the required and the Process Seal Antenna is the preferred choice, since it
does not require a spool piece. The cone antenna can also be used.
Ensure there is no edge between the ball valve and the nozzle/pipe, the inside should
be smooth.
Section 3: Mechanical Installation
November 2014
"Tank type and tank bottom type"
35