Diagnosis Methods for Cavitation in Warman Slurry Pumps

Methods for Detecting Cavitation in Slurry Pumps

The following techniques can be used to determine whether cavitation is occurring in a slurry pump:

a. Ultrasonic testing

b. External noise monitoring

c. Vibration analysis

1. Visual Inspection (Post-Damage Observation)

Visual inspection involves examining the damaged surface after cavitation has occurred. Cavitation, casting porosity, erosion wear, and corrosion can all cause surface damage, but their patterns differ:

Cavitation damage typically appears as a honeycomb structure, caused by localized high-speed liquid impact leading to metal fatigue. These pits are usually open to the surface and perpendicular to it.

Casting defects (e.g., porosity) often lie deep within the metal. Even if exposed by fluid flow, further mechanical removal will reveal internal voids.

Erosion wear usually forms grooves aligned with the flow direction, though vortex-induced patterns may complicate identification.

2. Noise Monitoring (External Noise Method)

This non-contact method is simple but has limitations:

Environmental noise interference can distort readings.

By the time noise levels peak, cavitation is often already severe and audible as intense cracking sounds.

Thus, this method is not ideal for real-time cavitation monitoring.

3. Vibration Analysis

This technique uses accelerometer probes to measure pump vibration frequencies. However:

Low sensitivity, especially for large, rigid pumps where structural stiffness dampens cavitation-induced vibrations.

Multiple vibration sources (e.g., mechanical imbalances) may mask cavitation signals.

Best suited as a supplementary monitoring tool rather than a primary method.

4. Ultrasonic Testing (Recommended Method)

Advantages:

Simple setup and calibration.

Immune to ambient noise interference.

High sensitivity to early-stage cavitation and its progression.

Ideal for real-time cavitation monitoring in pump stations.