Pyrometers are devices that are used widely in the industry for non-contact measurement of temperatures. Many manufacturing processes use heat energy in production and it is critical that the correct temperature is maintained at various control points throughout the production process.
In particular, the steel and glass industries use huge amounts of thermal energy and have long production processes. At numerous critical points through the process, it is essential to know the precise temperature at multiple locations to maintain the correct properties of the material that is being produced.
Pyrometers work by detecting the infrared (IR) radiation emitted by an object and this information is used by the pyrometer to measure the temperature.
With increased pressure on manufacturers to reduce energy consumption and emissions, pyrometers play an important role in ensuring that the correct temperature is maintained to reduce energy consumption, maintain quality and reduce waste.
The Key Benefits of Using Pyrometers in Manufacturing
A pyrometer measures the infrared radiation emitted by an object from a distance and is, therefore, able to measure temperature without contact.
A contact thermometer, in comparison, directly measures temperature by making physical contact with the object. It is important to consider these differences when choosing a temperature measurement device and select the one that best suits the intended application.
Pyrometers have many advantages over contact thermometers. Due to their remote sensing capability, they are suitable for more types of applications and are able to measure hot, moving objects in harsh industrial environments.
Why Is Accurate Temperature Measurement Important in Manufacturing?
Accurate temperature measurement plays an important role in many different industrial sectors where thermal processes need to be precisely monitored. Pyrometers provide the ability to accurately measure the temperature at a distance and have a very fast response rate, making them suitable for precise process control applications.
This temperature information ensures that the product is processed at the correct temperature to meet the design criteria and maintain the final product quality.
Pyrometers May Allow for Cost Savings in Manufacturing
Accurately measuring the process temperature at critical points during manufacturing can save energy by ensuring that the correct level of heat is used. If not enough heat is used and the product is not correctly processed, there may be quality issues and the parts could be rejected or scrapped later in the process.
Different Types of Pyrometers Are Available for Applications
There are many different types of pyrometers available that are suitable for different industry sectors and manufacturing processes. The vast range of pyrometers and accessories that are available can be overwhelming at first. If you need guidance and help selecting a suitable model, we recommend speaking to one of our product specialists to discuss your requirements by calling +44 (0)1823 668633.
In this blog, we’ll cover several different types of pyrometers:
- Portable pyrometers
- Single-colour pyrometers
- Dual-colour or ratio pyrometers
- Fiber optic pyrometers
- Hybrid pyrometers
What Are the Benefits of Portable Pyrometers?
A portable pyrometer is a handheld pyrometer that can easily be moved from one location to another for taking quick spot temperature measurements. The main advantage is that for a modest investment, a single pyrometer can take accurate temperature measurements at multiple locations around the plant.
They are provided with a viewfinder sighting optic so the user knows the exact location where the measurement is taken on the object. They are suitable for accurate non-contact temperature measurement on metals, glass, graphites and many other materials.
Advantages of Single Colour Pyrometers
Single-colour pyrometers are the most common type and operate at a single wavelength to measure the IR radiation emitted by an object. Selecting the correct model will depend on the material being measured and the temperature range required.
When selected correctly for given applications, a single-colour pyrometer will provide excellent measurement accuracy. Single-colour pyrometers have a price advantage compared with dual-colour.
A single-colour pyrometer is also more accurate than a dual-colour pyrometer on materials that change colour with temperature, such as when a surface tarnishes or oxidises as it is heated. For these applications, it can be better to select a single-colour pyrometer.
Advantages of Dual-Colour Pyrometers
A dual-colour pyrometer (also known as a dual-wavelength or ratio pyrometer) simultaneously measures the object’s temperature using two wavelengths. Effectively, it is two single-colour pyrometers contained within a single device. With this type of pyrometer, the temperature is calculated from the ratio of the two signals.
By ratioing the two signals, the pyrometer measures the colour distribution instead of just the signal intensity. The main advantage of a dual-colour pyrometer is that the measurement performance is not affected by contaminants in the air between the object and the pyrometer such as dust, steam or fumes. It is also less sensitive to contamination of the receiving optics by dust or other contaminants compared with a single-colour pyrometer.
For some applications, it also means the pyrometer is not affected by emissivity changes as there is a neutral change in both channels. Some ratio pyrometers can be used in different modes, such as single-colour, dual-colour or smart mode. This is to optimise the measurement performance depending on the intended application and to enhance the application range of the pyrometer.
Advantages of Dual-Colour Pyrometers:
Not affected by contaminants in the air. Dual-colour pyrometers are the right choice when there are fumes, smoke, steam or dust in the air between the pyrometer and the object being measured.
Not affected by contaminants on the optics. In dirty processes, it is likely that the optics will become contaminated, although it is possible to reduce the contamination by using an air purge. A dual-colour pyrometer is less susceptible to errors from optic contamination.
Better suited for measuring very small objects. A dual-colour pyrometer is a better choice when measuring very small objects as it will continue to measure correctly if part of the spot is not on the object.
Able to cope with emissivity changes. In some measurement applications, it is possible for the emissivity of the material to change. If this happens, the accuracy of a single-colour pyrometer measurement will be affected, unless the emissivity setting is adjusted accordingly. In many applications, dual-colour pyrometers are able to cope with this without the accuracy being affected.
We would advise discussing the details of your application with one of our product specialists, who can provide you with a recommendation for your specific requirements.
What Are the Benefits of Fiber Optic Pyrometers?
Fiber optic pyrometers can be used in a variety of applications where it is not safe or feasible to measure temperature using a traditional pyrometer, and they are available in single or dual-colour versions. They are ideal for use in close proximity to induction heating coils as the fiber optic cable is immune to the high electromagnetic radiation emitted by this heating method. They are also commonly utilised in high-temperature applications, such as in boilers, burners, industrial furnaces and kilns, where a traditional pyrometer would not be viable due to the extreme heat and the presence of electronics.
What Are the Benefits of Hybrid Pyrometers?
A hybrid pyrometer is a special type that combines both a pyrometer and a thermal imager in a single instrument. It accurately measures the temperature at a single point using the pyrometer and uses an infrared filter to show the auto-calibrated thermal image based on the pyrometer reading. This solution provides a very useful combination of thermal imaging and pyrometry in a single device.
The Impac ISR 6-TI is an example of this type of technology.
Different Models of Pyrometers Are Suitable for Different Manufacturing Processes
At LIMAB UK, we have a huge range of pyrometers, accessories and options covering all types of applications and manufacturing processes.
To learn more about LIMAB UK’s range of non-contact pyrometers, please visit our temperature measurement page.
To speak to a product specialist and find out how a pyrometer could benefit your company, call +44 (0)1823 668633. Alternatively, you can ask a question or schedule a call using our contact form. We’ll be more than happy to help you find the right pyrometer for your needs.
