You use many tools in your condition-based maintenance (CBM) program, but temperature sensors may be your biggest unsung heroes. They monitor the pulse of industrial machinery, turning heat and energy into data that gives you a window into the health of the equipment you depend upon.
Temperature sensors help form the backbone of advanced proactive maintenance strategies, from detecting bearing wear to predicting motor failures. Understanding temperature sensors will help you build an efficient CBM program and stay ahead of breakdowns.
What is a temperature sensor?
Temperature sensors are devices that measure and display the temperature of solids, liquids, and air by converting temperature changes into electrical signals. These thermal guardians catch temperature changes in industrial equipment, providing insights into the health and performance of the system.
Temperature sensors do this work in two primary ways:
- Resistance changes: Materials or semiconductors alter their electrical resistance with temperature shifts.
- Voltage changes: Sensors act like tiny power plants, measuring electrical currents that pop up when the junction between two different metals heats up.
Tiny electrical changes registered by these sensors give spot-on temperature readings and power sophisticated maintenance strategies. These sensors work as early warning systems, detecting subtle thermal anomalies that may indicate equipment failure.
They’re typically used to watch over:
- Bearings in rotating machinery
- Motor windings
- Process fluids
- Environmental conditions in sensitive areas
This sensor data helps your maintenance team preempt failures, optimize energy usage, and ensure product quality. As manufacturing processes get more advanced and enter the “smart factory” era, sensors are keeping pace. They’re getting more accurate, reacting faster to changes, and working better with the automation now more common on factory floors.
Types of temperature sensors
Temperature sensing technology offers a wide array of options, each with different characteristics, capabilities, and uses depending on the specific maintenance scenario at your workplace.
1. Resistive temperature detectors (RTDs)
RTDs are widely known for their high accuracy and precise temperature measurements. Platinum RTDs are especially versatile because they work reliably in both hot and cold conditions. They respond to temperature changes in a consistent, predictable way, making RTDs ideal for applications where you need good accuracy over the long term, like in sensitive industrial processes or scientific research.
2. Thermocouples
Thermocouples are widely used and usually made from two different metal wires joined at one end. They can measure a broad range of temperatures and come in various types that each use different metal combinations for certain temperature ranges. Their simple design makes them relatively inexpensive and reliable, even in harsh conditions. While not as precise as some other sensors, they’re popular in many industries, especially for extreme temperatures.
3. Thermistors
Thermistors are quick-reacting sensors that can pick up on small temperature shifts. A thermistor is made of materials that change electrical resistance when heated or cooled. There are two main types:
- NTC (Negative Temperature Coefficient): As the material gets hotter, it is easier for electricity to flow through.
- PTC (Positive Temperature Coefficient): As the material gets hotter, it is harder for electricity to flow through.
That behavior is what allows for quick temperature readings. You’ll find thermistors in places like car engines to monitor coolant temperature or in home thermostats to keep room temperatures steady.
4. Digital temperature sensors
Digital temperature sensors are a bit more technologically advanced. They measure temperature and convert it right away into signals and data. Many have built-in processing capabilities that let them integrate easily with other devices, eliminating the need for extra equipment to interpret temperature readings.
5. Infrared sensors
Infrared sensors are designed to measure temperature without contact, allowing for analysis of moving or dangerous objects from a distance. These sensors are ideal when physical contact with a surface is impractical or impossible.
Using temperature sensors in your CBM program
Ensuring optimal accuracy and reliability should be top priorities as you integrate temperature sensors into your CBM program. Here are some of the critical steps you’ll have to get right to make the most of it.
Select the right sensor
Think about the level of accuracy you need, the temperature range you want to measure, the required response time, and environmental conditions like exposure to corrosive substances or extreme conditions. For example, many organizations pick sensors with stainless steel housings for harsh environments because they help increase longevity and accuracy.
Install and connect
Install temperature probes correctly for them to perform properly. Use recommended connectors to ensure reliable data transmission, and consider thermowell for added protection in harsh environments. Properly installing sensors will make all the difference in ensuring their accuracy, and extending their longevity.
Data collection and analysis
It’s almost inevitable that you’ll integrate temperature sensors with automation systems to make it easier to collect and analyze data. Modern Computerized Maintenance Management Systems (CMMS) and other IoT solutions can aggregate data from multiple sensors, giving you insights into your equipment’s thermal health. Make sure to use datasheets from the manufacturer for reference when setting up parameters for notification thresholds and their responses.
Calibration and maintenance
Regular calibration is crucial for maintaining sensor accuracy over time. Develop a calibration schedule based on OEM recommendations and your specific operating conditions. Routine maintenance, including cleaning and inspection, helps prevent drift and ensures reliable temperature readings.
Applications in CBM
There are all sorts of scenarios where temperature sensors play a major role in your CBM programs:
- Equipment monitoring: Detect early signs of bearing wear or motor overheating
- HVAC optimization: Fine-tune system performance for energy efficiency and optimal air temperature
- Process control: Maintain precise temperature conditions in manufacturing processes
By strategically placing sensors to monitor both internal and surface temperatures, maintenance teams can predict potential failures, optimize energy consumption, and enhance overall system reliability.
Benefits of temperature sensors in CBM
By providing real-time insights into equipment health, sensors act as an early warning system, detecting subtle thermal anomalies that often precede failures, providing numerous benefits:
- Reduced unplanned downtime
- Extended asset lifespan
- Improved energy efficiency
- Better notification of temperature changes
- Cost savings realized through higher productivity lower downtime losses
- Better resource allocation due to improved maintenance planning
- Fewer interventions are needed to stop critical failures
- Reduced cost ownership for critical assets
By carefully selecting, installing, and maintaining your sensors, while leveraging the data they provide, you can drive substantial improvements in equipment reliability and operational efficiency.
The future of CBM: advances in temperature sensing
As industrial processes evolve, temperature sensors involved in condition-based monitoring programs will become increasingly sophisticated. Expect to see AI-driven sensor networks, self-healing systems, and nano-scale temperature monitoring revolutionizing maintenance strategies. By embracing these advancements, organizations can unlock new levels of operational excellence, driving innovation and competitiveness in an ever-changing industrial landscape.
