KROHNE DK 32-DK 34-DK 37 Safety V1 EN - Manual (Page 6)

3
DESCRIPTION
6
DK32 - DK34 - DK37
www.krohne.com 02/2012 - 4000574702 MA DK32 34 37 SIL R02 en
3.2 Functional principle
1 Magnetic coupling of a pointer at DK32, DK34 and DK37M8M
2 Magnetic field sensors at DK37M8E
The flowmeter operates in accordance with the variable area measuring principle.
The DK32, 34, 37 variable area flowmeters feature an upright tapered tube, wider end up, in
which a specially shaped float moves freely up and down.
The fluid flows upwards through the tube, causing the float to lift a certain distance and form an
annular gap between tube wall and float, until the forces acting on the float are in equilibrium.
At DK32, DK34 and DK37/M8M the position of the float in the measuring tube, representing a
certain flowrate, is transmitted by a magnetic coupling and displayed with a pointer on a scale.
At DK37/M8E the position of the float is detected with magnetic field sensors and the flow is
indicated on a digital bargraph indicator.
Strong deflecting magnetic fields can lead to deviations in the measured value.
MA_DK32_34_37_SIL_R02_en_574702_PRT.book Page 6 Thursday, March 1, 2012 9:53 AM