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When the injector (key 26) is set to operate, the odorizing
liquid is introduced into the station downstream pipe and its
volume will be replaced by an equal amount of natural gas.
Once the quantity set and controlled by means of the
sampler has been injected, the injection phase is terminated
and the solenoid valves (key 3 and 4) open.
Then the overpressure of 0.6 bar (8,7 psi) existing inside
the sampler is discharged into the main pipe downstream
of the regulation point, but upstream of the measurement
point where the quantity of gas is measured regularly (this
operation cannot be carried out in stations equipped with a
venturimetric gauge in case of relief valve or pressure loss
by the measuring assembly, consisting of pipe + counter
+ valves). In this case some gas shall be consumed, that
cannot be measured. The quantity should be around 1 Sm
each 10 liters (35 Scfh each 10 liters) of odorant. (for the
connection see diagram of figure 4).
At this point, the sampler (key 8) and the odorizer have
the same pressure level. The odorizing liquid found inside
the absorption-type odorizer, which in this mode functions
exclusively as a storage tank, flows freely through the filter
(key 25) and fills the sampler tank (key 8). The volume of
gas inside the sampler then flows through the solenoid valve
(key 3) and is then introduced into the main pipe upstream
from the measurement point.
During the sampler (key 8) refilling phase there is a gradual
emptying of the absorption-type tank (key 29). The volume
of liquid removed, is replaced with equal volumes of gas
coming from the upstream branch of the odorizer itself. Once
the established volume has been loaded, the two solenoid
valves (key 3 and 4) return to their non-working positions,
the sampler is pressurized once again and the system
resumes injection of the quantities calculated.
An analysis of the process explained above, indicates that
the Dosaodor-D system does not "CONSUME" gas and
that ALL of the gas collected upstream from the pressure
reduction unit is re-introduced downstream from it, but
upstream from the measurement unit.
Solenoid Injection Valve Setting Verification
Start the Dosaodor-D in AUTOMATIC with a gas flow at least
50% of the nominal.
Note: If the gas flow rate available is
less than this value, the process can be
completed later.
Check the recorded data on the position LOC:002: if the
value is lower than the specific volume indicated on the label
proceed by loosening the adjusting screw of the solenoid
injection valve EV2 by degrees. In general a preliminary
calibration is already set in the factory, an adjustment of
approximately half a turn should be sufficient.
After using some of the sampling cylinder charging, re-check
the value of the specific volume and compare it to the value
indicated on the label. If the range is ± 5%, the procedure can
be considered completed. Otherwise, proceed with a further
adjustment of the solenoid injection valve adjusting screw.
MAINTENANCE
Procedures and Recommended Timing
for Routine or Extraordinary Maintenance
Operations
The Dosaodor-D system, has been manufactured with the
state-of-the-art technology and materials currently available.
At regular intervals the Dosaodor‑D's
equipment condition should be inspected.
Specific procedures are prepared by the
3
service provider or end‑user according
national and applicable codes and
regulations. The frequency of inspection/
checks and replacement of part depends
upon the severity of service conditions,
applicable codes and national standards/
rules. If any odorant liquid or gas leakage
or gas escaping occurs, safety procedures
shall be applied to shut‑down the odorizing
system. For shutting down the Dosaodor‑D
when required, slowly reduce the pressure
in the system to avoid any possible damage.
Never open the equipment before the
pressure has been completely released.
Routine Maintenance (see figures 2, 3 and 4)
For routine maintenance operations, a Dosaodor-D
maintenance kit is required. This kit includes all spare
parts to be replaced in the system to renew it and keep it in
compliance with the functional specifications for which it as
been originally designed.
Note: To clean the pneumatic panel non
aggressive liquids must be used.
These are the operations to be carried out:
•
Wash by means of Natural Gas
•
Close all valves on the pneumatic panel (key 27)
•
Close the needle valve located on the pipe detecting the
odorizing pressure (low pressure branch)
•
Close the odorant outlet valve located on the tank from
which the odorant is collected.
•
Cut off the power supply to the electronic control unit
•
De-pressurize the panel by loosening the joint located in
the upper left part of the control cylinder
•
Replace all rubber parts inside the two pressure Filter-
Regulators model SA/2 (key 5 and 6)
•
Fully replace the two-way injection solenoid valve
(key 3) located on the top left of the pneumatic panel
•
Replace the moving assembly located inside the
three-way solenoid valve (key 4) that is used to control
opening/closing of the leaking circuit.
Dosaodor-D
WARNING
!
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