GEA VARIVENT D Series, Руководство по эксплуатации

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9.1.3 Cleaning the Leakage Cavity
Cleaning of the leakage cavity is performed using a spray nozzle in the double
disk that is connected to a valve seat cleaning pipe. Here, there can only be
general recommendations made as to how many and the length of the spray
cleaning, which are all dependent on the conditions occurring at each facility,
such as type of products, temperatures, cleaning means, cleaning intervals, etc.,
which could require more frequent or longer spray cleaning.
It is recommended to set the cleaning conditions in the system in a test phase, in
order to save cleaning medium. To optimize the seating cleaning, check the valve
after performing the cleaning to see if the valve seats are clean.
All appropriate systems for cleaning the valve should be regularly used to that an
optimal cleanliness is ensured and any damage to the valve is prevented. The
spray cleaner cleans the leakage cavity, while product flow can flow in both lines,
using a spray nozzle that distributes the CIP fluid throughout the leakage cavity.
However, the seal surfaces of the valve disc seals are not cleaned with them.
This type of leakage cavity cleaning should occur frequently with liquids which
are easily flushable, which do not stick to the seal surfaces or which eventually
crystallise.
9.2 Passivation
Before commissioning a plant, passivation is commonly carried out for long pipes
and tanks.
Valve blocks are usually excepted from this. Passivation is typically performed
using nitric acid (HNO
3
) at approx. 80 °C (176 °F) at a concentration of 3 % and a
contact time of 6 to 8 hours.
Cleaning
Passivation
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