KROHNE BM 70 M - Manual (Page 18)

18 BM 70 M
B) Solid antenna
6.1.4 Mounting on stilling wells/ trunks
Antenna Type Outside diameter
1s 76 mm (2.99”)
2s 100 mm (3.94”)
3 140 mm (5.51”)
3s 152 mm (5.98”)
4s 200 mm (7.87”)
If necessary, turn antenna to size!
Further requirements on stilling wells:
• The well must be electrically conductive.
•
Minimum inside diameter of well: 40 mm (1.57"). (BM 70 M: 80 mm, better > 100 mm).
• If possible, use only smooth walled, straight stilling wells. If nevertheless an assembled stilling
well is necessary, abrupt changes in diameter along the pipe should be less than 1 mm
(0.04"). Surface roughness of the inside of the pipe should not be more than + 0.1 mm
(0.004").
•
For the BM 70 M the antenna types 1s, 2s, 3s or 4s have to be used to achieve a high
measuring accuracy.
It is possible to measure through a full-bore open ball valve if the valve and the pipe adapters
above and below the valve are relatively smooth-walled.
It is not possible to measure levels below the end of the stilling well.
To ensure equalization of pressure, drill one or two small holes in the stilling well above the
maximum filling level.
800 mm