Recently, a device called a pyrometer has become widespread. What is this device and what is its essence? Its purpose is to measure the temperature of an object at a certain distance from it.
Using pyrometers, it is possible to safely obtain temperature indicators for hard-to-reach or incandescent objects, so they are indispensable assistants in any industrial production. Indeed, there are often situations when it is simply impossible to approach the measurement object, or it poses a danger to human health.
A bit of history
The first pyrometer (what this device is, read below) was invented by the Dutch physicist Peter van Mushenbrukt. These instruments could only measure body temperature visually. The main calculations were made from processing data on changes in the color and brightness of a hot object. Of course, these indicators were not accurate enough. Currently, the functionality of such devices has expanded significantly, this made it possible to measure the temperature of not only heated objects, but also those objects for which this indicator does not exceed 0 degrees. For example, an Optris infrared pyrometer measures temperatures in the range from -32 to +900 0 .
The improvement of these devices began in the 60s of the XIX century. This industry is successfully developing at the present time. Thanks to active development, it became possible to produce industrial pyrometers that were equipped with high technical characteristics. At the same time, with the development of nanotechnology, the size of devices became smaller every year, which made their use as convenient as possible.
The first portable model of the pyrometer was developed in 1967 by the leading American company Wahl. It was she who served as the prototype of modern infrared devices. The introduction of new technologies and developments has made it possible to improve the operation of the pyrometer. Its main principle was based on the determination of the thermal energy emitted by the object. With the widespread introduction of these devices, it became possible to measure remotely the temperature of both liquid and solid bodies.
The pyrometer thermometer today is classified according to several important parameters. Let's look at them in detail.
The main symptoms
According to this criterion, three main types can be distinguished:
- Bright. The temperature of a heated object is determined by comparing its color and the shade of the reference thread.
- Radiation. Such pyrometers determine the temperature of an object by the power of its thermal radiation.
- Color. This type of instrument estimates the temperature of an object based on the color reflection of its surface in various spectra.
Temperature range
In order to obtain accurate temperature readings, it is necessary to choose the correct pyrometer. What does this mean? This device has two types of modifications:
- Low temperature. Pyrometers of this type can only measure negative temperatures of objects.
- High temperature. These devices evaluate only heated items. Therefore, in such devices, one of the most important parameters is the limiting temperature of measurements.
Type of execution
A non-contact pyrometer is also classified by type of purpose:
- Portable models are a pocket-sized version of these devices. Such devices are indispensable when, when measuring the temperature of an object, it is impossible to approach it at a sufficient distance. Pyrometers of this kind are equipped with a small screen that allows you to display text and graphic information.
- Stationary devices. Stationary pyrometers are used for high-precision measurements. Such devices are in demand by large industrial enterprises where constant monitoring of the temperature performance of production is required.
Recommendation: employees who take temperature measurements very often are advised to pay attention to infrared pyrometers before purchasing the device. It also helps to compare the basic characteristics and cost of several samples available on the market. Below we provide a brief description of the four types of infrared pyrometers.
One-color models
An infrared (single-color) pyrometer is designed to measure a single wave of thermal energy. These models are inexpensive, they are an ideal portable option. The principle of their operation is very simple: just point the pyrometer at the object and press the appropriate button. Their indisputable advantage is the ability to measure temperatures from any distance.
These devices have a restriction on measuring the diameter of the spot, and are also very sensitive to environmental pollution. It is these shortcomings that significantly reduce the scope of their application, for example, in a smoky or very humid room, a single-color pyrometer will not work correctly.
Infrared thermocouples
One of the simplified varieties of infrared pyrometers is a thermocouple. The main feature of this device is the lack of complex electronics, which is used to amplify the received signal. This was his indisputable advantage, which provided a unique opportunity for the use of this device. The principle of operation of a thermocouple is quite simple: the resulting radiation is converted into a thermocouple nonlinear signal.
Benefits:
- low cost;
- good compatibility with measuring instruments;
- the maximum temperature is higher than other models.
It is also worth paying attention to the shortcomings. In principle, there are only two of them:
- an error of more than 2%;
- wide spectral range.
Two-color pyrometer - what is it?
This device appeared relatively recently. This is a more advanced model that measures the value of two or more emitted waves. The advantage of a two-color pyrometer, which significantly distinguishes it from traditional infrared devices, is the ability to work in different color spectra. It is these indicators that allow you to use this device in contaminated places, since it is not affected by the presence of foreign substances, such as smoke, gas, steam and others. Also, this pyrometer is indispensable in working with indicators of blackness, it will accurately determine the temperature of a solid metal turning into a liquid state.
Fiber Optic Pyrometers
The principle of operation of these devices is identical to traditional pyrometers. The only difference is the presence of a fiber optic cable through which the light flux is transported. The advantage of this configuration is that this cord can be arbitrarily bent. This makes it possible to take temperature measurements in the most inaccessible places.
Fiber optic pyrometers are widely used in places with a high electromagnetic field, where traditional models are completely powerless. Such devices are equipped with a fixed focus. It allows you to measure the radiation of thermal energy with a minimum spot diameter of 0.1 mm. However, such a focus sets limits on the distance: for accurate measurement, it is necessary to strictly observe the distance specified in the instructions.
Laser pyrometer
In order to carry out measurements at a long distance, manufacturers installed laser sights on the pyrometers . They come in several forms.
- A single-beam laser device makes it possible to aim the pyrometer only at the center of the thermal energy spot. Depending on the models of these devices, the sensitivity zone may have an error of 1-2 cm. Such a defect is most often found in inexpensive devices.
- Laser pyrometer with a double beam allows you to determine the size and location of the measured object. Use near is not recommended, since the indicators are often very high.
- Circular sights are the most accurate instruments that work efficiently at different distances and with any size of the spot being measured.
Instruction manual
When purchasing this device, it is necessary to check whether there is an instruction in the kit. The pyrometer is a complex device, so it will be quite difficult to figure out the functions yourself. The instructions describe the important points that are needed for proper operation. Here are some of them:
- output types and software;
- error data;
- inertia indicator;
- type of focus;
- temperature condition;
- spectral range;
- emissivity, etc.
Application of pyrometers
Infrared pyrometers are widely used in various industries:
- in thermal energy - when it is impossible to approach a heated object;
- in the electric power industry - pyrometers are used for continuous monitoring of objects and ensuring fire safety during their operation;
- in various laboratory studies - in the absence of the ability to touch the test subject, or when measuring its temperature does not work out in the usual way;
- in construction - pyrometers are used to determine the places of heat loss in homes and buildings for residential and industrial use, as well as on heating mains in order to quickly detect breakthroughs.