10
3 Product description
WIKA Operating Instructions - Differential pressure transmitter DPT-20
A metallic measuring cell is used as sensor element. The process
pressures are transmitted via the separating diaphragms and filling
oils to a piezoresistive sensor element (resistance measuring bridge
using semiconductor technology).
The difference between the acting pressures changes the bridge volt
-
age. This change is measured, further processed and converted into
a corresponding output signal.
When measurement limits are exceeded, an overload system protects
the sensor element against damage.
In addition, the measuring cell temperature and the static pressure
are measured on the low pressure side. The measuring signals are
further processed and are available as additional output signals.
P
P
5
4
6
6
3
2
1
Fig. 7: Configuration metallic measuring cell
1 Filling fluid
2 Temperature sensor
3 Absolute pressure sensor, static pressure
4 Overload system
5 Differential pressure sensor
6 Separating diaphragm
3.3 Supplementary cleaning procedures
The DPT-20 is also available in the version "
Oil, grease and silicone-
free
". These instruments have passed through a special cleaning
procedure to remove oil, grease and paint-wetting impairment sub
-
stances (PWIS).
The cleaning is carried out on all wetted parts as well as on surfaces
accessible from outside. To keep the purity level, the instruments are
immediately packed in plastic foil after the cleaning process. The
purity level remains as long as the instrument is kept in the closed
original packaging.
Caution:
The DPT-20 in this version may not be used in oxygen applications.
For this purpose, instruments are available in the special version "
Oil,
grease and silicone-free for oxygen applications
".
Functional principle
