KROHNE H250 M40 EN - Manual (Page 61)

TECHNICAL DATA
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H250 M40
www.krohne.com 11/2012 - 4000640702 MA H250 M40 R02 en
Technical data
8.1 Functional principle
The H250 flowmeter operates on the float measuring principle. The measuring unit consists of a
metal cone, inside of which a float can move up and down freely. The flow goes from bottom to
top. The float changes position so that the lifting force acting on it F1 is in equilibrium with the
form drag F2 and its weight F3: F3 = F1 + F2
1 For the indicator, the flow-dependent height of the float in the measuring unit is transmitted
by means of a magnetic coupling and displayed on a scale.
2 For a built-in signal converter (ESK4), the flow-dependent height of the float in the measuring
unit is detected by the S1 and S2 magnetic field sensors and electronically processed.
The flowmeter operates based on a modified float measuring principle. The guided float adjusts
itself so that the flow force acting on it is in equilibrium with the opposing spring force. The flow-
dependent position of the float in the measuring unit is displayed on a scale by means of a
magnetic coupling.
1 Indication principle M40 magnetic coupling
2 Magnetic coupling sensors
Operating principle of H250H and H250U
Figure 8-1: Operating principle H250H and H250U
1 H250H - horizontal flow direction
2 H250U - flow direction from top to bottom
MA_H250_M40_R02_en_640702_PRT.book Page 61 Wednesday, November 28, 2012 12:23 PM