One of a variety of techniques use in predictive maintenance (PdM) or enhanced FCAs.Propagation of pulse waves into objects and analysis of frequency (MHz) response.
Used to monitor bearings at slower speeds.
Ultrasonic and vibration techniques are often used in tandem to support one another.
Types of Ultrasound
- Airborne ultrasound
- Structure-borne ultrasound
The objective of ultrasonic inspection is:
Listed below are some of the different types of candidate assets for ultrasonic analysis:
A. Mechanical Assets
B. Electrical Assets
- High and low low speed rotating machinery
C. Other Assets
Applicable Conditions & Condition Grades
Listed below are the condition grades for this technology
A. Lubrication problems
B. Telltale stress wave problems
- Over lubrication condtions
- Under lubrication decisions.
C. Leak detection
- Coupling faults
- Damaged rotor bars
- Damaged bearings
D. Electrical dischagre
- Steam-trap leakage (turbulent flow)
- Pressure-safety-valve leakage
- Reciprocating-compressor valve leaks
- Electrical or coronal discharge leaks
- Locating air leaks (turbulent flow)
- Detecting and locating sources of electrical discharge (Ionization)
Process A. Before Analysis
Listed below are the key steps in the process:
B. During Analysis
- Identify low speed rotating machinery (under 60 rpm)
- Determine the synergistic tandem use of ultrasonic and vibration techniques
- Purchase the equipment or engage contractors
- Schedule and execute the work
C. After Analysis
high frequency signal is sent and reflected by the component (asset) in order to detect
early, small fatigue cracks or material structure defects / changes.
- Interpret the results
- Apply condition grades
- Report to stakeholders
- Make decisions
- Determine CAPA's, if any
- Determine next assessment interval
Listed below are some of the key attributes of ultrasonic inspection:
- It is a form of major maintenance
- It is typically performed by qualified 3rd party contractors
- It is conducted on variable intervals
Listed belows are some of the pros of ultrasonic inspection:
Listed below are some of the cons of ultrasonic inspection:
comprehensive monitoring program usually includes ultrasonic analysis
- Early detection can result in risk mitigation and cost savings
- A cost effective filter for identifying assets that should then be subject to vibration analysis.
- Cost of ownership is lower compared to vibration analysis
- Data is inexpensive to collect compared to some other technique
- Training required to operate the tool is less demanding than vibration analysis
- Good for optimizing of greasing programs
- Prone to data contamination from various sound sources
- Requires a capital investment in diagnostic eqiupment
- Requires staff training
Fig. The gradual degradation of assets over their design life.
Fig. Ultrasonic as one of the predictive maintenance (PdM) technologies
along the P-F Curve in relation to Potential Failure (P) and Functional
Fig. Comparing the Maintenance-Repair-Renewal (MRR) trade-offs at different organizations.
Alignment of the four different types of maintenance strategies across
the asset portfolio on decisions that are risk-based and consider the
whole-life of assets will result in a maintenance mix that is in
conformity with ISO 55001 standards.