Condition-based maintenance or CBM is a proactive maintenance strategy to monitor the equipment performance and maintenance need using real-time data. CBM or condition-based maintenance identifies the state of the asset by sensor collected real-time data. When the data warns for the machine condition to be unsatisfactory, maintenance is performed. Condition-based maintenance avoids unnecessary time-bound maintenance tasks and maximizes productivity by reducing downtime.
Condition-based maintenance philosophy decides the equipment condition by:
- Visual inspections
- Various NDT tests
- Real-time data gathered by sensors.
Working of Condition-based Maintenance
Condition-based maintenance works using the following three simple steps:
- Capturing sensor data,
- Communicating data, and
- Performing maintenance work.
Capturing Sensor Data
In this stage of the Condition-based maintenance philosophy, various non-destructive tests are performed using condition-monitoring sensors. Such sensors check the conditions of the machine. The main parameters that are checked during the equipment working condition are vibration, temperature, pressure, etc. Some of the widely used condition-monitoring sensors include:
- Accelerometers: They measure vibration, velocity, and displacement.
- Infrared Cameras: They can detect heat and displays results on a thermal image.
- Fluid Condition Sensors: These tools observe the fluid condition.
- Tank Level Sensors: These sensors check and monitor the fluid level in a tank.
- Pressure Transducers: They measure fluid pressure. (Both liquids and gases)
- Ammeters: They gauge the current running through a circuit.
When a CBM sensor finds any monitored parameter out of its operating range, it must be communicated properly to a technician for remedial action. The communication may be in any form like an alarm, message, PLC, HMI, or SCADA.
Performing Maintenance Work
Once the sensor-monitored data creates a notification the maintenance team is alerted for fixing the problem. A work order is created and the maintenance of the equipment is performed.
Benefits of Condition-based Maintenance
Condition-based maintenance provides various advantages like:
- Optimized Time Spent on Maintenance, Over maintenance is eliminated.
- Increase plant efficiency by correcting performance-affecting issues.
- Less Disruption of Production.
- Increase employee safety by confirming the equipment is in good condition.
- Lowered Chance of Catastrophic Failure.
- Reduced Asset Downtime.
- Increased profitability.
- Improves worker safety.
- Improve reliability and ROI for equipment.
- Reduces the possibilities of collateral damages.
- Quicker problem diagnosis.
Implementing Condition-based Maintenance Philosophy
Condition-based maintenance in any plant can be implemented as follows:
- Identify your critical and expensive equipment that may cause serious loss or risk.
- Determine the most appropriate tools to detect the equipment degradation or failure possibility.
- Set thresholds to trigger CBM alerts when there is a deviation in data from the normal condition.
- Manage and organize the data.
- Appoint the right person who can take necessary action based on the data.
Types of Condition-based Maintenance
There are various types of CBM techniques. Some of the most widely applied condition-based maintenance examples:
- Vibration Analysis for rotating equipment like pumps, turbines, compressors.
- Acoustic testing for detecting leakages.
- Operational Performance to detect temperature, pressure, flow rate, etc.
- Electrical Checking to detect current reading, voltage, etc.
- Ultrasonic Testing to detect subsurface defects.
- Infrared thermography to find high-temperature conditions.
- Oil analysis to analyze oil health, contamination, and machine wear.
Disadvantages of Condition-based Maintenance
There are some drawbacks of condition-based maintenance like:
- The significant initial cost to perform criticality analysis and sensor placement.
- Training of associated personnel.
- Software requirement to handle the massive data from sensors.
- Uniform wear failures may not be detected sometimes.
- Unpredictable maintenance period.