TL;DR

CIP pump cavitation reduces flow rate and can damage the impeller. Check the inlet strainer, suction conditions, and tank level before adjusting the pump.

What you might see

CIP flow rate below setpoint
rattling or crackling noise from the CIP pump
pressure fluctuation on CIP supply line
pump motor current fluctuating

Likely causes

Tap to mark as ruled out

CIP tank level low reducing net positive suction head (NPSH) available
Suction strainer partially blocked with product debris
Pump speed (VFD setpoint) set too high for the suction conditions
Air ingress at a suction flange joint or valve packing

Required tools

Suction pressure gauge
LOTO kit
Strainer cleaning brush
Chemical-resistant gloves

Safety first

CIP chemical solution in the pump and suction line is caustic or acidic. Wear chemical-rated PPE when opening the suction strainer or any CIP line.
Running a centrifugal pump against a closed discharge valve for more than a few seconds causes rapid temperature rise in the pump casing. Do not run dry or against a closed valve.

Procedure

6 steps · ~30 min

1
Check the CIP tank level. Low level is the most common cause of cavitation on a centrifugal CIP pump.[1]
2
Lock out the CIP pump and inspect the suction strainer. Clean out any product debris, label fragments, or CIP chemical scale.[1]
3
Inspect the suction piping flanges and valve stems for air ingress. Soap solution or a pressure test can identify air leaks.
4
Verify the pump speed (VFD frequency) is within the range that keeps suction pressure above the NPSH required for this pump.
5
Check the suction pipe bore for partial obstruction from a collapsed hose or incorrect valve position.
6
After restoring suction conditions, restart the pump and verify the cavitation noise stops and flow rate recovers.

Sources

Tetra Pak Sani-Matic CIP-100 / 200 CIP / SIP System general technical documentation, Tetra Pak
Sani-Matic CIP-100 / 200 CIP system general pump maintenance and cavitation procedures (general)

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