Using remote seals with pressure measuring device for hazardous areas:
● When using remote seals with pressure transmitters in hazardous areas, the permissible
ambient temperature limits for the pressure transmitter must not be exceeded. Hot surfaces
on the cooling section (capillaries or cooling elements) are a possible source of ignition.
Initiate suitable measures.
● When remote seals with a flame arrestor are used, the pressure measuring instrument
determines the permissible ambient temperature. In the case of potentially explosive
gaseous atmosphere, the temperature around the flame arrestor must not 60 °C.
5.4.2
Installation of the remote seal with the capillary line
Notes
● Do not rest the measurement assembly on the capillary line.
● Do not bend capillary lines; risk of leakages and/or risk of considerable increase in the
response time of the measuring system.
● Owing to the risk of bending and breakages, pay attention to mechanical overloads at the
joints such as capillary line-remote seal and capillary line-measuring instrument.
● Unwinding the excess capillary lines with a radius of at least 150 mm.
● Fasten the capillary line such that there are no vibrations.
● Permissible height differences:
– When installing the pressure measuring instrument above the measuring point, keep
the following in mind:
in the case of remote seal measuring systems with silicone, glycerin or paraffin oil filling,
the maximum height difference of H
1max
= 7 m must not be exceeded.
– If halocarbon oil is used as a fill fluid, this maximum height difference is H
1max
= 4 m, see
installation type G.
If negative overpressure is observed during measurements, reduce the permissible height
difference accordingly.
Installing/mounting
5.4 Installing "Remote seal"
SITRANS P320/P420 (mA/HART)
Operating Instructions, 06/2018, A5E44852162-AA
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