8
TECHNICAL DATA
76
H250 M40
www.krohne.com
03/2020 - 4000640706 - MA H250-M40 R06 en
8.1 Functional principle
The H250 flowmeter operates in accordance with the float measuring principle. The measuring
unit consists of a metal cone in which a float can move freely up and down. The medium flows
through the flowmeter from bottom to top. The float adjusts itself so that the buoyancy force F1
acting on it, the form resistance F2 and its weight F3 are in equilibrium: 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 (ESK4A), 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 in accordance with 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.
Figure 8-1: Measuring principle - general
1
Indication principle M40 magnetic coupling
2
Magnetic coupling sensors
Figure 8-2: Measuring principle for H250H and H250U
1
H250H - horizontal flow direction
2
H250U - flow direction from top to bottom