Depending on the cleaning method (medium, concentration, temperature and
contact times), the seals are affected to different degrees. This can impair the
function and the service life.
In order to meet the EHEDG requirements and to guarantee correct cleaning of
the valve, the recommended cleaning pressure is between 1 - 5 bar with a flow
speed of ≥ 1.5 m/s.
With several inlets and outlets, like for the housing combinations A, E and C,
separated flows are to be avoided, since this would lead to lower flow speeds.
We therefore recommend to clean the upper and lower pipelines separately and
then clean the valve disk.
9.2
Passivation
Before commissioning an installation, passivation is usually carried out for long
pipes and vessels.
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.
Hint!
TEFASEP® gold valve seat seals achieve optimum sealing only after
an initial CIP or SIP cleaning Operating conditions CIP or SIP cleaning:
- Medium: Lye, hot water or saturated steam
- Temperature: >80 °C (176 °F)
- Holding time: 20 … 30 min
The valve must be brought to the closed position for a brief period (3
minutes) immediately after CIP or SIP cleaning. During
commissioning, regularly check all sealing points for leaks. Exchange
defective seals and repeat the CIP or SIP process.
Cleaning
Passivation
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