VEGA VEGAPULS 51K…54K 4 … 20 mA; HART compact sensor - Manual (Page 19)

VEGAPULS 51K … 54K 19
21750-EN-031222
Mounting and installation
DN 50
ø50
> 500 mm
Tube antenna system with ball valve cutoff in measur-
ing tube
Ball valve
Vent hole
Deflector
Surge pipe with ball valve
If a ball valve is mounted in the surge pipe,
maintenance and servicing can be carried
out without opening the vessel (e.g. if it con-
tains liquid gas or toxic products).
A prerequisite for trouble-free operation is a
ball valve throat that corresponds to the pipe
diameter and provides a flush surface with
the pipe inner wall. The valve must not have
any rough edges or constricted areas in its
channel. The distance to the sensor flange
should be at least 500 mm.
Guidelines for standpipe construction
Radar sensors for measurement on surge or
bypass tubes are used with G 1½ A screw-
on antenna or in the flange sizes DN 50,
DN 80, DN 100 and DN 150. The radar sen-
sors with a DN 50 flange only forms a func-
tioning measuring system when used in
conjunction with a measuring tube.
The illustration on the left shows the construc-
tional features of a measuring tube (surge or
bypass tube) as exemplified by a radar
sensor with DN 50 flange.
The measuring pipe must be smooth inside
(average roughness Rz
≤
30). Use stainless
steel tubing (drawn or welded lengthwise) for
construction of the measuring pipe. Extend
the measuring pipe to the required length
with weld-on flanges or with connecting
sleeves. Make sure that no shoulders or
projections are created during welding. Be-
fore welding, join pipe and flange with their
inner surfaces flush and exactly fitting.
Avoid welding through the pipe wall. The pipe
must remain smooth inside. Roughness or
welding beads on the inner surfaces must be
carefully removed and burnished, as they
cause false echoes and encourage product
adhesion.
The following illustration shows the construc-
tional features of a measuring tube as exem-
plified by a radar sensor with DN 100 flange.
If the vessel contains agitated products,
fasten the measuring pipe to the vessel bot-
tom. Provide additional fastenings for longer
measuring pipes.