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5.2 Installation with by-pass:
See Annex 6
START-UP:
Begin with all valves closed .
• Slowly open the by-pass valve to pressurise the down-
stream piping .
• When the pressure is balanced downstream, slowly
open the small upstream valve V1 . The pressure varia-
tion should not exceed 0 . 3 bar per second .
• When the pressure is balanced in the meter, slowly
open the main upstream valve and then close V1 .
• Slowly open the downstream valve and check that the
meter starts to register the flow .
• Gradually, close the by-pass valve . Check that the flow
rate doesn't exceed the capacity of the meter .
SHUT DOWN:
• Slowly open the by-pass valve and then close the up-
stream and downstream valves on the meter line .
• Carefully open the small bleeder valve V2 and depres-
surise the meter . The pressure variation should not ex-
ceed 0 . 3 bar per second .
• Some gas still inside the meter and the pipe, therefore
sufficient ventilation is required .
5.3 Installation without by-pass: See Annex 7
START-UP:
Begin with all valves closed .
• Slightly open the upstream valve to pressurise the me-
ter line . The pressure variation should not exceed 0 . 3
bar per second . When the pres sure is balanced, fully
open the upstream valve .
• Slightly open the downstream valve . The valve should
be opened a small amount to maintain:
– The upstream pressure in the meter line .
– A low flow rate in the meter during the down
stream pressurisation (approx . 5% Qmax) .
When the downstream pressure is balanced, the downs-
tream valve can be completely opened .
SHUT DOWN:
• Very slowly close the downstream valve and check
that the meter is no longer recording .
• Close the upstream valve .
• Slowly open the small bleed valve V2 . The pres sure var-
iation should not exceed 0 . 3 bar per second .
• Some gas still inside the meter and the pipe, therefore
sufficient ventilation is required .
5.4 Meters placed after a regulator
Installation has to be done in accordance with the
technical manual of the specific regulator . During pres-
surisation and depressurisation, insure that the pressure
variation should not exceed 0 . 3 bar per second .
6 Maintenance
6.1 Maintenance of the meter
Once installed, the meter does not require any specific
attention except a periodical check or change of the lu-
bricant filled in the covers .
After start-up:
Natural gas: After the preliminary term of service, the lu-
bricant level should be checked .
Other gases: After a working period of 100 hours from
commissioning, the lubricant level should be checked .
If the lubricant level is appreciably low, if the lubri cant is
emulsified or if there is a chemical reaction between the
lubricant and the gas, the lubricant should be reassessed
and changed to fit the pre vailing conditions .
Periodical change of lubricant:
The period between checks or changes of lubri cant de-
pends of the operating conditions (pres sure variation,
flow rate . . . ) .
Natural gas: Under normal conditions, lubricant has to
be changed every 5 to 8 years . When the meter is used
with extremely clean gas the period can be extended .
Other gases: Please consult us .
Use solvent and alcohol free product to clean the meter .
Repair must be done only by qualified personal . After-
wards a tightness test with 1 . 1 x PS (Pmax) must be per-
formed .
If used with wet gas, internal and external effect of cor-
rosion has to be checked regularly and in case of severe
corrosion, the meter has to be replaced . Spare parts:
When changing pressure containing parts, ensure that
spare parts that comply with the PED are used .
6.2 Maintenance of optional equipment
6.2.1 LF and HF transmitters
These transmitters do not require any specific mainte-
nance . The function of the transmitters can be checked
by comparing the electronic index with the meter index .
6.2.2 Filter
If an increase of pressure loss is noticed, the filter should
be checked and cleaned/replaced before any mainte-
nance on the meter .
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