Recommended Installation; Start Up; Installation With An Upstream Valve; Installation With Upstream And Downstream Valves - ITRON MZ Mode D'emploi

• (7) Pressure pulses must be avoided
during starting and operating to preser-
ve the turbine wheel. To prevent dama-
ge during starting, increase the pressu-
re slowly at less than 0,3 bar per se-
cond.

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 respec-
ting the following rules:
• Use preferably elbow pieces with large
radius (> 5 DN) to be installed at the
inlet of the meter.
• For diameter variations, use preferably
concentric convergent and divergent
pieces; sudden changes must be avoi-
ded.
• Obstacles such as thermowells must
not protrude in the pipe within 2 DN
upstream of the meter. Gaskets should
be correctly centred between the flan-
ges and not protrude 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
pressure 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 slow-
ly the upstream valve (max. 0,3 bar/se-
cond). When the pressure is stabilised in
the meter, open gently the downstream
valve to maintain the pressure in the me-
ter 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 ma-
ximum flow of the meter is not exceeded.

4 Transmitters

The MZ is equipped as option with 2 Low
Frequency (LF), Reed switches and an anti-
tampering switch; with inductive medium
or high frequencies (HF) transmitters. A
Cyble sensor can be also installed onto
the totaliser, see Annex 3.
Remarks about using the meter in poten-
tially hazardous areas (ATEX)
• Pulse transmitters must be connected
to circuits intrinsic safe circuits, accor-
ding to EN50020.
• All exposed aluminium parts must be
suitably protected (using paint, varnish,
etc) if a film of rust is possible from dust
in the environment.
• The meter must be earthed.
• Tools used for installing, removing, or
repairing the meter on site must be ap-
propriate for use in the hazardous area
bearing in mind that the hazardous
area classification during meter repla-
5