bürkert 8201 Bedienungsanleitung Seite 23

CIP procedures (clean in place)
The following cleaning steps are very common for CIP procedures for internal cleaning of a system
with pH sensors (cold water rinsing steps between the different cleaning steps are not described).
Cleaning products Concentration Temperature
Base 1.2 to 2 %
Acid 1.5 %
Steam
Important!
• Avoid unnecessary long cleaning steps with base to reduce the enamel corrosion and so to
maximise the live time of the electrode.
• Increasing the fluid temperature by 10 °C close at the limiting curve (see diagram 2) doubles
the corrosion rate.
• Cleaning with alkaline products impairs the gel layer at the surface of the pH enamel. This
leads to a zero point offset which causes measuring errors of up to 0.5 pH for a short while di-
rectly after cleaning step.
• This zero point offset can be eliminated by forming/conditioning the sensor during a shutdown
SIP procedure or by rinsing with hot water (see also section 4.1 Form/condition sensor). Pay at-
tention to the regeneration times for forming/conditioning according to diagram 3.
SIP procedures (sterilise in place)
The following cleaning products are permitted for CIP procedures for internal cleaning of a facility with
integrated pH sensors.
•
Process medium
•
Steam
• Alcohol solutions
•
Aseptic solutions
Important!
•
If the sensor was not conditioned sufficiently, the sterilisation process using steam may lead to
the formation of a stable source layer on the surface of the pH enamel. This newly formed
table source layer leads to a slight zero point offset
•
Correct this zero point offset with a one-point calibration at the measuring transmitter.
Cleaning time
Up to approx. +85 °C Up to 1 h
Approx. +60 °C Approx. 15 min or longer
Approx. +134 °C Up to 2 h
Diagram 3:
Regeneration times for forming/conditioning
the pH sensor following alkaline cleaning
in order to eliminate measuring error in con-
nection with the temperature of the regenera-
tion product water
Note
The 8201 pH sensor works temperature shock
resistant up to ΔTmax = 120 °C;
ΔT = medium temperature minus sensor tem-
perature (see also technical data)
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