Operating Instructions

Table Of Contents
4.3.3 Orientation in a vessel with obstructions
Polarization reference point
For best results on a vessel with obstructions, or a stillpipe with openings, orient the front or
back of the device toward the obstructions. For an illustration, see Device orientation
(Page 30).
1
2
3
Polarization axis
Polarization reference point
Display
4.3.4 Mounting on a Stillpipe or Bypass Pipe
A stillpipe or bypass pipe is used for products with a low dK, or when vortex or extremely
turbulent conditions exist. It can also be used to provide optimum signal conditions on foaming
materials. See Dielectric constant of material measured in Performance (Page 165) for more
information.
The pipe diameter must be matched with the antenna size. Use the largest antenna size that
will fit the stillpipe/bypass pipe
1)
. See Threaded Horn dimensions (Page 181), Raised-Face
Flange per EN 1092-1 (Page 215), Flanged encapsulated dimensions (Page 190)or
Hygienic encapsulated dimensions (Page 194).
One continuous length of metallic pipe is preferred, without joints.
Any false reflections created by joints/welds/imperfections will lead to inaccuracies of the
measurement.
Joints (if unavoidable) must be machined to ± 0.25 mm (± 0.010") and must have welded
connecting sleeve on the outside.
If using any hygienic process connections in conjunction with a stillpipe/bypass, please
ensure that the antenna/lens are cleanable in accordance with the applicable approval.
Installing/mounting
4.3 Proper mounting
SITRANS LR250 with mA/HART
Operating Instructions, 10/2019, A5E32220602-AG 29