Installing/mounting
4.2 Mounting location
SITRANS LR250 (PROFIBUS PA)
Operating Instructions, 01/2014, A5E32221386-AB
21
4.2.5
Stillpipe or Bypass Pipe requirements
●
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 177) or Raised-Face
Flange per EN 1092-1 (Page 194).
●
One continuous length of metallic pipe is preferred, without joints. Bad joints create
reflections.
●
Joints (if unavoidable) must be machined to ± 0.25 mm (± 0.010") and must have welded
connecting sleeve on the outside.
1)
Mounting in a pipe greater than 100 mm (4") can cause large errors, and therefore is not
recommended.
Suitable pipe diameters:
Horn antenna
40 to 100 mm (1.5 to 4")
PVDF antenna
50 mm (2") only
Flanged encapsulated antenna 50 to 100 mm (2 to 4")
Not recommended:
> 100 mm (4")
Bypass vent:
Required at the upper end of the bypass
1)
1)
To equalize pressure and keep the liquid level in the bypass constant with the liquid level in the
vessel.
4.2.6
Device orientation
Bypass pipe installation
Stillpipe installation
①
Vent
①
Align front or back of device with stillpipe slots
1)
②
Align front or back of device with
vents
1)
②
Slots
1)
Horn antenna version shown as example
