Endress+Hauser Cerabar M PMC41, Техническая информация

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Cerabar M
Hauser 65
Ambient temperature range The filling oil, capillary length, capillary internal diameter, process temperature and the oil volume of the
diaphragm seal determine the ambient temperature range of the diaphragm seal system. The operating range
can be extended by using a filling oil with a smaller expansion coefficient and by using a shorter capillary.
Installation instructions Instructions for diaphragm seal systems
• The diaphragm seal together with the transmitter form a closed, calibrated system, which is filled through
openings in the diaphragm seal and in the measurement system of the transmitter. These openings are sealed
and must not be opened.
• In the case of devices with diaphragm seals and capillaries, the zero point shift caused by the hydrostatic
pressure of the filling liquid column in the capillaries must be taken into account when selecting the
measuring cell. If a measuring cell with a small measuring range is selected, the sensor nominal range can
be violated as a result of position adjustment.
• For devices with a temperature isolator or capillary, a suitable fastening device (mounting bracket) is
recommended.
• When using a mounting bracket, sufficient strain relief must be ensured in order to prevent the capillary from
buckling (capillary bending radius
≥
100 mm).
Installation instructions
In order to obtain more precise measurement results and to avoid a defect in the device, mount the capillaries
as follows:
• Vibration-free (in order to avoid additional pressure fluctuations)
• Not in the vicinity of heating or cooling pipes
• Insulate if the ambient temperature is below or above the reference temperature
• With a bending radius of
≥
100 mm.
Vacuum applications
For applications under vacuum, Hauser recommends mounting the pressure transmitter below the
diaphragm seal. This prevents a vacuum load of the diaphragm seal caused by the presence of fill fluid in the
capillary.
When the pressure transmitter is mounted above the diaphragm seal, the maximum height difference H1 - as
illustrated in the following diagram - must not be exceeded. The maximum height difference depends on the
density of the filling oil and the smallest ever pressure that is permitted to occur at the diaphragm seal (empty
tank), see the following illustration on the right. Glycerine is not suitable for vacuum applications.
1) Version for feature 70 "Process connections" in the order code
2) Versions with 1 m (3 ft) capillary, see also feature 80 "Transmitter mounting; fill fluid"
P01-PMP4xxxx-11-xx-xx-xx-001
Installation above the diaphragm seal
P01-PMP75xxx-05-xx-xx-en-011
Diagram of maximum installation height above the diaphragm seal for
vacuum applications
H 1
0.0
2.0
4.0
6.0
8 .0
10.0
12.0
50 100 300 400 500 600 7 00 8 00 900 1000 200
Inert oil
High temperature
oil
Vegetable oil
Silicone oil
Pressure at diaphragm seal [mbarabs]
Height
dif
ference
H1
[m]
Low temperature oil