Vessel Characteristics; Disturbing Objects; Valves - Emerson Rosemount 5402 Reference Manual

Mechanical Installation
October 2018
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 has built-in functions which optimize measurement performance for
various bottom shapes (see
3.3.10

Disturbing objects

The Rosemount 5400 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 can be isolated from the process by using a valve.
Use a full-port ball valve.

The Rosemount 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.

Valves can be combined with stilling wells.
34
"Tank type and tank bottom type" on page
Reference Manual
00809-0100-4026, Rev KC
103).
Mechanical Installation