Endress+Hauser Deltabar PMD78B - Product Description; Product Design Overview; Differential Pressure Measuring Cell

Deltabar PMD78B PROFINET with Ethernet-APL Product description
Endress+Hauser 11
3 Product description
3.1 Product design
3.1.1 Measuring cell for differential pressure with metallic
membrane
+ -
p
1
p
2
p
1
1
2
3
4
5
4
p
2
A0043081
 1 Capillary on the second side (P1) is optional
1 Measuring element
2 Middle diaphragm
3 Fill fluid
4 Internal membrane
5 Membrane of the diaphragm seal
p
1
Pressure 1
p
2
Pressure 2
+ -
p
1
p
2
p
1
1
2
3
44
p
2
5
A0043082
1 Measuring element
2 Middle diaphragm
3 Fill fluid
4 Internal membrane
5 Membrane of the diaphragm seal
p
1
Pressure 1
p
2
Pressure 2
The pressures applied are transferred from the membrane of the diaphragm seal to the
internal membrane of the measuring cell by means of an incompressible fill fluid. This
causes a deflection of the membranes on both sides. A second fill fluid transfers the
pressure to a side of the measuring element where a resistance bridge is located
(semiconductor technology). The change in the bridge output voltage, which depends on
the differential pressure, is measured and processed further.