Endress+Hauser Deltabar PMD75B HART - Product Description; Product Design; Measuring Cell for Differential Pressure with Metal Process Membrane; Flow Measurement

Deltabar PMD75B HART Product description
Endress+Hauser 11
3 Product description
3.1 Product design
3.1.1 Measuring cell for differential pressure with metal process
membrane
+ -
p
1
p
1
1
2
3
44
p
2
p
2
A0043083
1 Measuring element
2 Middle diaphragm
3 Filling oil
4 Process membrane
p
1
Pressure 1
p
2
Pressure 2
The process membranes are deflected on both sides by the acting pressures. A filling oil
transfers the pressure to a side of the measuring element where a resistance bridge is
located (semiconductor technology). The differential-pressure-dependent change of the
bridge output voltage is measured and further processed.
3.1.2 Flow measurement
Flow measurement with Deltabar and differential pressure sensor:
Q Q
Q ~ Q ~
∆ ∆p p
+ +
– –
p
1
p
1
p
2
p
2
A B
A0038340
A Orifice plate
B Pitot tube
Q Flow
Δp Differential pressure, Δp = p
1
– p
2
Advantages:
• A customized unit can be specified.
• Low flow cut off: when activated, this function suppresses small flows which can lead to
large fluctuations in the measured value.