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Keep this manual easily accessible for all users . Please
respect all national rules for installation, operation and
service of gas meters .
1 Characteristics
Turbines gas meters are flow meters . The flow of gas
turns a turbine wheel and the rotating speed of the tur-
bine is proportional to the linear speed of the gas . The
movement is mechanically transmitted to the totaliser
through the magnetic coupling . Detailed characteristics
are given in Annex 1
2 Packing of the MZ
2.1 Packing
The meter, depending on the size is delivered in an in-
dividual carton box or on a wood pallet . The packaging
contains the plugs for the installed transmitters and the
lubricant when an oil pump is installed .
2.2 Storage
If the meter is not going to be used immediately, it
should be stored under cover in a clean, dry environ-
ment . The caps fitted at the inlet and the outlet pipe
must stay in place until installation . Storing temperature:
-40 °C to +70°C .
2.3 Handling
Meters should be handled with care . They must be lifted
only with belts around the main body or on the eyelets .
3 Installation
3.1 General recommendations:
See Annex 2 and PED information in Annex 6
• The standard MZ is designed for use with clean and
non-aggressive gases . For use with aggressive gases
please contact Dresser Actaris Gas for special versions .
• If the meter is equipped with an oil pump, turn oil tank
according to the installation position .
• (1) Before installation, check visually that the meter has
not been damaged during transport .
• (2) Do NOT weld pipework with a meter installed .
• (3) The meter should be installed without stress in the
pipework . The flanges must be correctly lined up . The
tightening torque of the bolts must not exceed (Nm):
M16
M20
85
170
Please tighten bolts in opposite pairs .
• (4) To ensure accuracy, The meter has to be installed
with an inlet straight pipe of 3 DN minimum .
• (5) Transmitters connection: Gas Meters are often in-
stalled in areas where there is a risk that Gas will be
present . Therefore, electrical connections to meters
need to be made with consideration of the use of Ex
marked equipment or otherwise approved circuits .
For plug assignment and pulse values refer to the
main name plate .
• (6) Dirt particles may damage the turbine wheel
therefore the use of starting sieve and filter are recom-
mended .
• (7) Pressure pulses must be avoided during starting
and operating to preserve the turbine wheel . To pre-
vent 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 metrolo-
gy can be affected by disturbances existing in the flow
of gas .
The best accuracy is achieved by respecting the follow-
ing 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 con-
vergent 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 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 op-
erate . Increase slowly the pressure in the downstream
pipe (max . 0,3 bar/second) . When the downstream pres-
sure 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 stabi-
lised in the meter, open gently the downstream valve to
maintain the pressure in the meter and to avoid over-
flow .
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