Publicité
Les langues disponibles
Les langues disponibles
Measurement in the
bypass tube
LEVEL TRANSMITTER 8136 • 4 ... 20 mA/HART - two-wire
Constructive requirements:
•
Material metal, smooth inner surface
•
Preferably pultruded or straight beaded stainless steel tube
•
Welded joint should be straight and lie in one axis with the holes
•
Flanges are welded to the tube according to the orientation of the
polarisation
•
When using a ball valves, align the transitions on the inside and fix
accurately
•
Gap size with junctions ≤ 0.1 mm
•
Surge pipes must extend all the way down to the requested min.
level, as measurement is only possible within the tube
•
Diameter of holes ≤ 5 mm, any number OK, on one side or com-
pletely through
•
The antenna diameter of the sensor should correspond to the
inner diameter of the tube
•
Diameter should be constant over the complete length
Instructions for surge pipe extension:
•
The ends of the extension tubes must be bevelled and exactly
aligned
•
Welded connection via external U profiles according to illustration
above. Length of the U profiles should be at least double the tube
diameter
•
Do not weld through the pipe wall. The surge pipe must remain
smooth inside. Roughness and beads on the inside caused by
unintentional penetration should be removed since they cause
strong false echoes and encourage buildup
•
An extension via welding neck flanges or pipe collars is not recom-
mended.
An alternative to measurement in a surge pipe is measurement in a
bypass tube outside of the vessel.
4 Mounting
21
Publicité
