What is a Pyrometer?
Pyrometers, also known as infrared thermometers, radiation thermometers, or non-contact thermometers, are used to measure the temperature of an object’s surface, which is determined by the radiation (infrared or visible) emitted from it.
Pyrometers function as photodetectors due to their ability to absorb energy and measure the strength of electromagnetic waves at any wavelength.
These are used to assess high-temperature furnaces. These devices can monitor temperature with high accuracy, precision, purity, and speed.
Pyrometers come in a variety of spectral ranges (metals have short wave ranges, whereas nonmetals have long wave ranges).
Color pyrometers measure the radiation emitted by an object during a temperature measurement.
These are capable of measuring the temperature of an object with high accuracy.
As a result, these instruments have extremely low measuring errors.
Color pyrometers are utilized to calculate the ratio between two radiation strengths over two spectral regions.
These are accessible in the Metis M3 and H3 series, as well as the handheld portable Capella C3 in various configurations.
High-speed pyrometers are employed to determine temperature more quickly and accurately than M3 devices.
These are accessible in conjunction with one- and two-color pyrometers.
These devices can provide unambiguous temperature profiles for fast-moving items and maintain an appropriate temperature level.
Working Principle of Pyrometer
Pyrometers are temperature measuring devices that detect both the temperature of an object and the electromagnetic radiation it emits.
These can be obtained in several spectral ranges.
Pyrometers are categorized into three types based on their spectral range:
- One-color pyrometers,
- Two-color pyrometers, and
- High-speed pyrometers.
The pyrometer’s primary basis is to detect the temperature of an object by sensing the heat (or) radiation emitted from it without making contact with it.
It records the temperature based on the intensity of the radiation emitted. The pyrometer consists of two main components:
- Optical system &
- Detectors
that are utilized to measure the surface temperature of an object.
When an object’s surface temperature is measured with the pyrometer, the optical system captures the energy radiated by the object.
The radiation is then transmitted to a detector that is very sensitive to radiation waves. The detector’s output indicates the temperature of the object owing to radiation.
It is important to note that the temperature of the detector used to analyses the level of radiation is exactly proportional to the temperature of the item.
The radiation released by each targeted object at its real temperature exceeds the absolute temperature (-273.15 ° C).
This released radiation is known as infrared, as it is above visible red light in electromagnetic spectrum.
The radiated radiation is utilized to detect the object’s temperature, which is then translated into electrical impulses by the detector.
Types of Pyrometers
Pyrometers are divided into two types for measuring the temperature of various objects. They are:
- Optical pyrometers
- Infrared / Radiation Pyrometers
1). Optical pyrometers
These are examples of pyrometers that detect visible-spectrum thermal radiation.
The temperature of hot things measured will be determined by the visible light they emit. Optical pyrometers may visually compare the surface of a target object to a calibrated light source.
When the filament and the object’s surface have the same temperature, the thermal radiation intensity created by the filament merges with the targeted object’s surface and becomes invisible.
This procedure converts the current going through the filament into a temperature level.
2). Infrared (or) Radiation Pyrometers
These pyrometers are intended to detect thermal radiation in infrared range, typically at a distance of 2-14um. It derives the temperature of a target object from the radiation it emits.
This radiation may be aimed at a thermocouple and converted into electrical impulses.
Because the thermocouple can provide a larger current equal to heat it emits.
Infrared pyrometers are composed of pyroelectric materials such as
- Polyvinylidene Fluoride (PVDF),
- Triglycine Sulphate (TGS), and
- Lithium Tantalate (LiTaO3).
