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Idiomas disponibles
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• (7) Pressure pulses must be avoided during
starting and operating to preserve the
turbine wheel . To prevent damage during
starting, increase the pressure slowly at less
than 0,3 bar per second .
3.2 Recommended installation
Turbine meters are flow meters therefore
their metrology can be affected by distur-
bances existing in the flow of gas .
The best accuracy is achieved by respecting
the following rules:
• Use preferably elbow pieces with large ra-
dius (> 5 DN) to be installed at the inlet of
the meter .
• For diameter variations, use preferably con-
centric convergent and divergent pieces;
sudden changes must be avoided .
• Obstacles such as thermowells must not
protrude in the pipe within 2 DN upstream
of the meter . Gaskets should be correctly
centred between the flanges and not pro-
trude into the pipe .
3.3 Start up
3.3.1. Installation with an upstream
valve
Open the valve very slowly until the meter
starts to operate . Increase slowly the pres-
sure in the downstream pipe (max . 0,3 bar/
second) . When the downstream pressure is
stabilised, open the valve completely .
3.3.2 Installation with upstream and
downstream valves
Close the downstream valve . Open slowly
the upstream valve (max . 0,3 bar/second) .
When the pressure is stabilised in the meter,
open gently the downstream valve to main-
tain the pressure in the meter and to avoid
overflow .
3.3.3 Installation with a by-pass
Close all valves . Slowly open the by-pass
and wait until the downstream pressure is
stabilised . Then proceed as §3 . 3 . 2 . Close the
bypass .
After start up, please check the tightness of
the installation . Check also that the maxi-
mum flow of the meter is not exceeded .
4 Transmitters
The MZ is equipped as option with 2 Low
Frequency (LF), Reed switches and an an-
ti-tampering switch; with inductive medium
or high frequencies (HF) transmitters . A Cyble
sensor can be also installed onto the totalis-
er, see Annex 3 .
Remarks about using the meter in potential-
ly hazardous areas (ATEX)
• Pulse transmitters must be connected to
circuits intrinsic safe circuits, according to
EN 60079-11 .
• Clean the meter head only with a damp
cloth .
• All exposed aluminium parts must be suit-
ably protected (using paint, varnish, etc)
if a film of rust is possible from dust in the
environment .
• The meter must be earthed .
5
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