Siemens SITRANS P, Руководство по эксплуатации, Страница: 55 / 280

● Do not cause damage to the remote separating membrane; scratches on the remote
separating membrane, e.g. due to sharp-edged objects, are the main starting points for
corrosion.
● Select suitable gaskets for sealing.
● Use a gasket having an adequately large inner diameter for flanging. Insert the gasket
concentrically; contact with the membrane leads to deviations in measurements.
● When using gaskets made of soft materials or PTFE: follow the guidelines of the gasket
manufacturer, especially regarding the tightening torque and setting cycles.
● At the time of installation, use suitable fastening components such as screws and nuts that
are compliant with fitting and flange standards.
● Excessive tightening of screwed joints on the process connection may displace the zero
point on the pressure transmitter.
Note
Commissioning
If a shut-off valve exists, open the shut-off valve slowly when commissioning in order to
avoid pressure surges.
Note
Permissible ambient and operating temperatures
Install the pressure measuring device such that the permissible limits of ambient and
measured medium temperatures are not overshot or undershot even with the consideration
of the effect of convection and heat radiation.
● Note the effect of temperature on the measuring accuracy.
● When selecting the remote seals, ensure that fittings and flange components have
adequate pressure-temperature resistance by selecting suitable materials and pressure
ratings. The pressure rating specified on the remote seal applies to reference conditions
according to IEC 60770.
● For the maximum permissible pressure at higher temperatures, please refer to the
standard specified on the remote seal.
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.
Installing/mounting
5.4 Installation with remote seal
SITRANS P320/P420 with 4 to 20 mA/HART
Operating Instructions, 11/2019, A5E44852162-AC
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