Use
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EXTRAORDINARY
Every generator must be periodically stopped to carry out a thorough inspection and maintenance: required interval is determined
by your experience, by the operating conditions, by the quality of supply water and the type of fuel used.
Before inspection or cleaning, thoroughly check that no water or steam can reach the generator through the connecting ducts.
Each valve will have to be locked and, if necessary, isolated by removing a section of the connection pipe to the system or by
placing a blind flange in-between.
During inspection, also check all accessories giving top priority to safety valves, level probes and pressure switches.
Level switch replacement
To change the safety level switch or any of its parts, it is necessary to carefully follow these instructions:
1) Check the integrity of the new ceramic holder.
2) Check rod length.
3) Ensure that rod is coaxial to holder axis.
4) Check the integrity of the electric system, especially the resistor of the circuit connecting the ceramic holder to the electric
panel (resistance must be over 10 MOhm).
5) Check level switch operation, including the two ceramic holders and their relays with conductivity trip points.
The replaced parts must have the same characteristics as the original ones. To carry out calibration, refer to the
Technical Manual and, if in doubt, contact the manufacturer.
STORAGE DURING IDLE PERIODS
The most significant corrosion often occurs during idle periods. The operations to be carried out to ensure a correct storage of the
generator mainly depend on the duration of the stop time.
'Dry' storage can be arranged when the generator has to stay idle for a long period of time and 'wet' storage for short idle periods
or when the generator is a spare one and should be able to be operating in a short time.
In both cases, the required operations tend to eliminate the causes of any corrosion.
Dry storage
Empty and thoroughly dry the generator, then inject a desiccant (such as quicklime, silica gel, etc.) inside the cylindrical body
Wet storage
Drain water and perform a complete cleaning of the generator. Fill the body up to the normal operating level and, after a short
evaporation time, blowdown to the atmosphere to eliminate all dissolved gases. Then completely fill the generator, with a correct
metering of DEHA (diethyl hydroxyl amine) to develop a residual concentration of more than 100 ppm preventing the attacks of
the oxygen dissolved in water. Add also trisodium phosphate to ensure a total alkalinity above 400 ppm. Then close all connections.
successivamente tutte le connessioni.
Inspect all connections to make sure there is no leakage and take water samples at regular intervals, checking that alkalinity does
not change.
A "wet" storage is always recommended because it better guarantees proper storage and a lower time required to achieve
operating conditions.
Cooke Industries - Phone: +64 9 579 2185 Email: [email protected] Web: www.cookeindustries.co.nz
