KROHNE H250 M40 Safety V1 EN - Manual (Page 6)

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DESCRIPTION
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H250 M40
www.krohne.com 02/2012 - 4000904201 MA H250 M40 SIL R01 en
3.2 Functional principle
The flowmeter operates in accordance with the float measuring principle.
A metal cone is installed in the measuring unit H250, in which a suitably shaped float can move
freely up and down.
The flowmeter is inserted into a vertical pipeline and the medium flows through it from bottom to
top.
The guided float adjusts itself so that the buoyancy force A acting on it, the form drag W and
weight G are in equilibrium (G = A + W).
An annular gap results which width depends on the current flow rate.
The height of the float in the measuring unit, which depends on the float, is transmitted by a
magnetic coupling and displayed on a scale.
Strong deflecting magnetic fields can lead to deviations in the measured value.
Figure 3-1: Functional principle
MA_H250_M40_SIL2_R01_en_904201_PRT.book Page 6 Thursday, March 1, 2012 10:08 AM