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BA / RE 250 / EN / V17-11
Installation
Process connection
max. torque
EN1092-1
ANSI B16.5
Nm
ft lbf
15
½”
14
10
25
1”
14
10
40
1 ½”
25
18
50
2”
25
18
80
3”
35
25
100
4”
42
30
Tab 2.2
Tightening torques for devices with PTFE liner
Magnetic filters
To prevent a malfunction of the flowmeter caused by ferromagnetic substances contained in the
medium (such as weld beads) a magnetic filter should be mounted in flow direction upstream of
the instrument.
This kind of filter is also recommended if such particles cannot be avoided in standard operation.
3.3 Operating principle
Like other devices of this series the variable area flowmeter
RE 250
operates according to the
principle of flotation:
The measuring unit consists of a metal tube with a measuring ring in which a float can move up
and down. The media is flowing upwards through the tube and raises the conical float. Here the
annular gap enlarges until the equilibrium between the buoyancy force F
A
, the drag force F
S
and
the weight of the float F
G
is reached. The adjusted height of the float is directly proportional to
the flowrate. The movement of the float is transmitted via a magnet inside the float to a
corresponding magnet inside the display unit outside of the measuring pipe.
Fig. 1
Operating principle of the RE 250
