To measure the temperature of various surfaces, various sensors are used, including a pyrometer. It works quite simply and quickly. And what is a pyrometer, let's figure it out.
Content
What is a pyrometer?
A modern engineering device for determining the temperature of any object, based on an infrared sensor, is called a pyrometer. He is also known as thermodetector, temperature data logger, digital thermometer or infrared gun. The operation of the device is based on the principle of determining the temperature value of the surface of an object by thermal electromagnetic radiation its surface.The pyrometer captures invisible infrared radiation, converts it into degrees, and displays the result on the display. A non-contact and fast method of examining the necessary objects allows specialists to avoid possible injuries.
Application area
Sufficiently widespread use was found for pyrometers in those industries where a large number of heating devices are installed. In the field of construction and thermal power engineering, they are used to calculate the heat loss of structures, including a pyrometer that helps to identify damage to thermal insulation.
In industry, such devices make it possible to analyze the temperature of various processes remotely. This is necessary, for example, in mechanical engineering, metallurgy and other industries.
So, electricians check the level of heating wire connection points, and car mechanics check the heating of machine parts. Pyrometers come to the aid of scientists during the implementation of various studies or experiments: this is how they determine the correctness of the temperature indicators of substances and bodies.
In everyday life, people use such devices to determine body temperature, water, food, etc.
Types and classification
Depending on the functional feature, there are several classifications of pyrometers.
According to the essential method used in the work:
- infrared;
- Optical.
Optical pyrometers are divided into:
- Brightness;
- Color, or multispectral.
According to the image of aiming, devices with optical or laser sights are distinguished.
According to the applied emissivity, pyrometers with a variable and a fixed coefficient are distinguished.
According to the possibility of transportation, pyrometers are divided into stationary and mobile (portable).
Based on the possible range of measurements, there are:
- low-temperature (-35…-30 °С);
- high-temperature (+400 °С and above).
Device and principle of operation
The basis of the structure of the pyrometer is the detector of infrared radiation. The data is converted by the built-in electronic system and displayed on the display.
A typical pyrometer is shaped like a pistol with a small display. The compact control panel, laser guidance and high accuracy in close interaction with the object explain the demand for the tool among workers in engineering and technical fields.
The main working elements of the pyrometer are considered to be a lens, a receiver, as well as a display on which the measurement result is displayed. The principle of operation of the pyrometer is as follows: infrared radiation is emitted from the object under study, and through a lens it is focused and sent to the receiver (thermopile, semiconductor, thermocouple).
If a thermocouple is used, the voltage changes as the receiver heats up. Resistance - in the case of semiconductors. These changes are converted into temperature readings.
In order to take a measurement, you just need to point the pyrometer at the object, put it into action and note the result. Using a special button, you can adjust the temperature measurement format - Celsius or Fahrenheit.
Specifications
The pyrometer has a number of parameters that characterize its functionality. The choice of the desired model of the device is carried out according to their values. Let's turn to the main ones.
Optical resolution
This is the name of the indicator of the ratio of the diameter of the spot of the tool to the distance to the object. This function depends on the angle of the lens of the device: the larger it is, the more area it can cover. The most important factor in measurement accuracy is the imposition of the spot exclusively on the surface material. If the area is exceeded, the measured value is likely to be inaccurate.
REFERENCE. Each pyrometer model has a different optical resolution. The difference between them is impressive, for example, from 2:1 to 600:1. The last ratio is typical for professional devices. As a rule, they are used in heavy industry. The optimal ratio for household and semi-professional pyrometers is 10:1.
Working range
The operating range of the device depends on the pyrometric sensor and often varies from -30 °C to 360 °C. So, almost all types of pyrometers are suitable for domestic use, given the maximum temperature of the coolant in the heating system up to 110 ° C.
Error
The error implies the level of possible deviations of the temperature values and depends on the accuracy of the pyrometer. On average, permissible deviations are not exceeding 2% of the norm.
Emissivity
This parameter is the ratio of the power of the current temperature radiation to the same indicator of the reference absolutely black body.
REFERENCE. For matte materials, the emissivity is 0,9-0,95. For this reason, more devices are selected for this value.The result will be noticeably different from the real one, for example, in the case of measuring the degree of heating of the surface of shiny aluminum.
For more accurate measurements, many models are equipped with a laser pointer. In this case, the light beam is not located in the center, but indicates the optimal boundary of the measurement area.
Advantages and disadvantages
Like any other device, the pyrometer has its advantages and disadvantages. Their presence is explained by the nuances of the device and the conditions of use.
pros
- Mobility, small size and very simple design;
- Affordable low cost, due to the use of a minimum number of elements in the design;
- High level of reliability;
- Sufficiently wide measurement range.
Minuses
- Direct dependence of the pyrometer readings on the emitted ability of the object under study;
- The accuracy of the measurement results may be lower due to the peculiarity of the physical state of the surface of the object;
- The function of amending the indicators and establishing the error is provided only on the newest instruments;
- Distance plays a big role in measurement accuracy.
Most Popular Models
EOP-66
Pyrometer EOP-66 is used in the implementation of scientific and laboratory research. It is designed to measure the indicators of surfaces of objects at temperatures from +900 to +10000 ° C,
This stationary model is equipped with a telescope, which consists of an objective and an ocular microscope. The two-lens lens has the ability to focus at a distance of up to 25.4 cm, and its optical resolution is 3:1. Please note: the telescope of this device is fixed on the base and moves smoothly in a horizontal plane.
Kelvin X 4-20
This is a high-precision pyrometer, which has a universal range for determining temperature indicators: from -50 to +350 ° C, a very high speed of action - 0.2 s. The use of the tool is provided in the range of 8-14 microns.
This pyrometer combines the capabilities of both mobile and stationary devices. This is due to the compact dimensions (17x17x22 cm) and the presence of a mounting socket for mounting the M12 lens. The manufacturer guarantees absolute water and dust resistance. Thus, the presented model of the pyrometer can be used in complex manufacturing and construction industries.
S-700 "Standard"
This non-contact device is preferably used, for example, in construction or metallurgy. It adequately serves as an infrared detector for determining the degree of heating of the surfaces of loose and solid objects, as well as molten and flowing materials.
The temperature range ranges from +700 to +2200 °C, which is typical for high-temperature devices. Expansion of the possibility of interaction with external media is achieved through two options for the output interface: analog output 4 - 20 mA or digital RS-485.
REFERENCE. It is possible to purchase an optical pyrometer at a very affordable price: the minimum cost of such a device is 6,000 rubles, the maximum is 30,000 rubles.
How to measure temperature with a pyrometer
After purchasing the device, you must carefully study the instructions for it.Despite the very simple requirements for operation, reckless actions can lead to significant distortions in temperature values. The process for correctly measuring temperature with a pyrometer is as follows:
- Turn on the pyrometer device;
- Determine the material from which the object is made (for example, steel or copper);
- Then, depending on the instrument model, enter the emissivity as an edit on the display;
- Point the beam of the infrared pyrometer at the surface to be measured;
- Define the boundary of the measurement spot using the laser pointer.
With this sequence of measurements, you will get results that are closest to the actual temperature.
The pyrometer is a universal and indispensable device in terms of its functionality. Having understood the nuances of its operation, it can be easily used both in the professional field and in everyday life.
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