FISCHER Mess- und Regeltechnik GmbH
Product and functional description | 2
BA_EN_DA03_GKT_HLP_ATEX
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2.3 Intended use
The DA03 serves to display differential pressures in neutral gaseous and fluid
media.
If used with aggressive media, the media compatibility with the materials used
must be checked (see Techn. data).
The DA03 can be delivered with a contact element. If the set limit values are ex-
ceeded, the output power circuits are opened or closed, and/or a 0/4…20 mA
output signal proportional to the displayed value is issued for a capacitive rota-
tion angle encoder.
DANGER
Installation regulations
The respective installation instructions must be observed for every application
case. These should be listed in detail in the same-named section in chapter 'As-
sembly' for the 'use in explosive areas'.
2.4 Function diagram
1
2
3
4
5
6
7
8
8
Fig. 7:
Function diagram
1
Motion train
2
Transfer lever
3
Measuring shaft
4
Pressure transfer fluid
5
Measuring membranes
6
Connecting rod
7
O-ring (pressure relief valve)
8
Pressure chamber
2.5 Design and mode of operation
The pressures in the pressure chambers that are to be compared are each ex-
erted onto a measuring membrane that can be rigidly connected using a con-
nection rod. To compensate the static pressure, the space between the measur-
ing membranes is filled with a pressure transfer fluid.
During pressure equalisation, the two measuring membranes are in an idle pos-
ition. In case of pressure difference, the force acting on the membranes causes
it to be moved towards the side of the lower pressure.
The connecting rod transfers the deflection of the measuring membranes onto
the transfer lever mounted to the measuring shaft. Proportional to the current
differential pressure, the measurement shaft makes a rotational movement that
the indicator translates into a rotation angle between 0 and 270°.
