During the 1960s, a significant advance in infrared temperature measuring came about with the introduction of ratio or two-colour infrared thermometry.
This technology uses two infrared sensors within the transmitter, each sensor being sensitive to a specific and different infrared wavelength. The output from the sensors is fed into a microprocessor where an energy 'ratio' is calculated by dividing one sensor signal by the other.
Standard or single-colour infrared thermometers are greatly affected if the IR energy is obscured or attenuated, because they rely for accuracy on the total amount of infrared energy emitted from the product reaching the sensor. In the case of molten metals, specifically irons and steels, the emitted infrared energy tends to be nonlinear and changes with temperature and wavelength, thus making standard thermometer inaccurate for these applications.
Ratio thermometers measure a ratio function or 'slope' between the infrared energy detected by two sensors and are not affected by atmospheric sighting problems, ie dust, steam or particulates which reduce the amount of energy transmitted because the slope between the sensors does not change.
Since the accuracy of a ratio thermometer is not affected by a reduction in the amount of IR energy reaching the unit, the target field-of-view of the thermometer does not have to be filled, ie the temperature of a product that is smaller than the field-of-view is measured accurately with excellent resolution.
Similarly, when measuring the temperature of products with nonlinear emissivities, the slope is not affected. There are many two-colour Raytek units installed in South Africa, measuring difficult and demanding applications. Some of these applications are:
* Monitoring klinker temperature and refractory in cement kilns, where dust is a problem.
* The nonlinear emissivity problem of monitoring the temperature of steel when poured from a furnace has been solved at two major plants. This solution has also reduced the usage of dip thermocouples.
* A ferro-silicate plant, where the sighting of the product is difficult, and where there are also problems of nonlinearity of emissivity.
* A ceramic insulation fibre plant where the field-of-view of a stream of 'molten ceramic' at 2000°C is only 5 mm in diameter.
The above are a few examples where ratio (two-colour) infrared thermometers have solved problems that would be impossible for standard (one-colour) thermometers.
Noncontact infrared temperature control in aluminium rolling process Instrotech
Temperature Measurement
The aluminium rolling process is critical to the aluminium manufacturing industry, where precise temperature measurement is essential for ensuring high-quality product output and protecting equipment. The Optris long-wavelength camera can accurately measure strip temperatures in cold rolling and coiling applications.
Read more...Where simplicity meets reliability Endress+Hauser South Africa
Temperature Measurement
The new iTEMP TMT31 temperature transmitter from Endress+Hauser combines simplified selection, ordering, installation and operation with the highest reliability and long-term stability in one product.
Read more...Automating car window defrosters
Temperature Measurement
Window defrosters are vital features in vehicles, particularly in colder climates. The automotive manufacturer seeks an efficient solution to quickly and precisely measure the temperature of the windows, ensuring that the connections, installed cables and wires work correctly and have no defects before the vehicle’s final release.
Read more...The impact of thermal imaging in steam methane reformers
Temperature Measurement
As global demand for hydrogen, ammonia and fertilisers increases, LAND is empowering steam methane reformer operators to unlock efficiency gains at existing plants to meet ambitious production targets while also safely decarbonising.
Read more...Proven indicators monitored in three dimensions ifm - South Africa
Temperature Measurement
The VVB30x continuously detects vibrations in three measurement axes and uses them to calculate proven indicators for evaluating machine condition.
Read more...Digital display electronic sensors Transducer Technology
Temperature Measurement
The Trantech TTED series is a versatile range of digital display sensors designed for high-accuracy measurement of pressure, flow and temperature.
Read more...Quality process control instrumentation Instrotech
Temperature Measurement
Instrotech is a leading provider of high-quality process control instrumentation and industrial automation solutions that are designed to optimise efficiency, reliability and safety across industries.
Read more...Three ways to conduct thermal inspections Comtest
Temperature Measurement
There’s no universal solution for all infrared inspections with a Fluke thermal camera, also known as a thermal imager. You need to match your method to the type of equipment you’re inspecting and the level of detail you require.
Read more...Modern N1020 temperature controller
Temperature Measurement
Temperature control is a fundamental aspect of maintaining the integrity and quality of products in industries such as food processing, pharmaceuticals and healthcare. The N1020 temperature controller, designed for precision and reliability, addresses the stringent requirements of these sectors by offering advanced features and robust functionality.
Read more...Safer, simpler temperature measurement ABB South Africa
Temperature Measurement
ABB has launched an enhanced version of its NINVA TSP341-N non-invasive temperature sensor, delivering safer and simpler temperature measurements for applications in the chemical, oil and gas industries.
printer friendly version