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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 installa-
tion . Check also that the maximum 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 potentially 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 suitably protect-
ed (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 appropriate for use in the haz-
ardous area bearing in mind that the hazardous area
classification during meter replacement may differ
from that during normal meter operations .
• The meter shall not be exposed to flames, ionising ra-
diation, and ultrasound .
• Pulse values and maximum frequencies are given in
Annex 1 . Electrical characteristics and wiring of the
socket are given in Annex 4 . The wiring of the trans-
mitters is written on the name plate of the meter .
• Ambient temperature conditions must be considered,
including possible addi tional heating effects due to
other de vices in immediate vicinity .
5 Maintenance
When properly installed and put into service, the MZ
need no particular attention and will provide you with
many years of satisfactory service .
5.1 Lubrication
Meters equipped with an oil pump have to be periodi-
cally lubricated . Oil is delivered with the meter . Specific
oil has to be used, for example
– Aeroshell fluid 12 MIL6085A
– Isoflex PDP38 (Klüber)
– Anderol 401D (Mobil Oil)
– Univis P38 (Shell)
6
Quantity of oil to be filled:
a) On commissioning to fill the volume between the
pump and the bearings
DN
Oil vol . (cm
50/80
100
150/200
b) In Service
DN
Oil vol . (cm
50/80
100
150/200
c) Recommended lubrication periodicity
Application
Dry gas, no dust
Gas comprising
light condensates
and little dust
Gas with high
percentage
of condensates
and dust .
BIOGAS
applications
5.2 External silicagel cartridge
The meter can be equipped with an external silicagel
cartridge for installation in severe environment condi-
tions . The cartridge has to be replaced when its colour
has changed . To replace the cartridge, unscrew the old
cartridge, remove the protective plug of the new car-
tridge and screw it into the totaliser .
5.3 Inspection and repair
It is possible to check the good functioning of the MZ by
applying a spin test . This test will give information about
eventual friction in the turbine ball bearings .
The test has to be conducted as follow:
• Accelerate the turbine wheel around 30 to 50% of
Qmax then to measure the time until the turbine
wheel stops .
• Measure the spin time (ST) until the turbine wheel
stops .
• See Annex 5 for typical values of spin time .
3
)
Push
4
20
5
25
6
30
3
)
Push
0,5
2-3
0,8
4
1,0
5
Lubrication periodicity
6 months
Monthly
Weekly
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