9
TECHNICAL DATA
46
BW25
www.krohne.com
10/2008 • 4000432301 MA BW25 R01 en
Technical data
9.1 Operating principle
The device works according to the displacement principle.
The length of the displacer rod
4
corresponds to the measuring range
2
.
The displacer rod
4
suspended from a measuring spring
1
is immersed in the liquid and
detects a lifting force, which is proportional to the mass of the displaced liquid.
Each change to the rod weight corresponds to the change in the length of the spring and is thus a
measure of the filling height.
The expansion of the spring and thus the measuring stroke is transmitted to a display using a
solenoid coupling from the measuring chamber.
If the device cannot be installed from above, e.g. because there is an agitator in the tank, then
there is a special bypass chamber available for side mounting.
The lift of the proportional rod is dependent on the density of the product.
The level indication must be displayed for the liquid to be measured.
The difference in density between the tank atmosphere and liquid must be at least 100 g/l.
The atmospheric pressure and temperature must be known.
Due to the length of the spring suspension pin
3
, the unmeasureable area is L = 340 mm.
1
Measuring spring
2
Measuring range
3
L
≥
340mm
4
Displacer rod
MA_BW25_R01_en_PRT.book Page 46 Thursday, October 30, 2008 3:49 PM
