Predictive Maintenance: Temperature Monitoring
Most equipment are designed to operate within certain temperature ranges, therefore monitoring the operating temperatures of equipment is a good way of tracking their “health”. Tracking the operating temperature regularly would be a good way to identify possible issues such as mis-alignment, wear, and lubrication at early stages. The following are a few ways to monitor the operating temperature of equipment:
- Thermography: This is a good method for checking the general condition of equipment. This method allows one to spot-check equipment looking for abnormal temperature levels and “hot spots”. This method is most effective when high-definition thermography cameras ($$$$) are used where one can have precision imaging and temperature readings to detect small temperature variances across the machinery.
- Thermocouples and RTDs (Resistance Temperature Detectors): Both sensors use Base Metal resistance to determine the temperature. Because of the Base Metal and construction methods, RTDs are more accurate and have higher repeat-ability. These sensors are good for monitoring temperatures at specific locations continuously.
To use these sensors the equipment would have to physically be modified to accommodate the sensors which increases the implementation cost. Therefore, they are typically used on more expensive/critical equipment.
- RFID (Radio-frequency identification) Temperature sensors – With the advent of technology, RFID sensors are becoming an economical alternative to the above-mentioned options and are being used more and more. These sensors use electromagnetic fields to automatically identify and track sensors attached to objects. The sensors are wireless and contain digitally-stored information which allows them to simultaneously monitor multiple conditions such as temperature, humidity, locations, etc.
There are two types of sensors: Passive and Active. Passive sensors collect energy from a nearby RFID reader's interrogating radio waves. Active sensors have a local power source and can operate hundreds of feet from the RFID reader.
These sensors are easy to install and do not require any modifications to the equipment. The sensors can be read with either portable or fixed readers. The portable readers provide instantaneous temperature data for periodic monitoring where as fixed readers provide continues data gathering capability.
Implementing a temperature monitoring program could be a good first step as a part of a broader Predicative Maintenance Program.