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 6
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 pressure 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 downstream
pressurisation (approx 5% Qmax)
When the downstream pressure is balanced, the down-
stream 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 pressure
variation 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 techni-
cal manual of the specific regulator During pressurisation
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:
6
Natural gas: After the preliminary term of service, the
lubricant 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 lubricant 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 prevailing conditions
Periodical change of lubricant:
The period between checks or changes of lubricant de-
pends of the operating conditions (pressure 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
performed
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