Principle And Application Of Infrared Thermometer

In nature, all objects whose temperature is higher than absolute zero will constantly emit infrared radiation energy to the surrounding space. The size of infrared radiation energy and its distribution according to wavelength are closely related to its surface temperature. Therefore, the surface temperature of an object can be accurately measured by measuring its infrared radiation energy, which is the objective basis of infrared radiation temperature measurement.

Today we will analyze the infrared thermometer, understand its principle and application.

1. Principle of infrared thermometer

The infrared thermometer consists of optical system, photoelectric detector, signal amplifier, signal processing and display output. The infrared radiation energy of the target in the field of view of the optical system is collected, and the size of the field of view is determined according to the optical parts and their positions of the thermometer. The infrared energy is focused on the photodetector and converted into corresponding electrical signals. This signal will pass through the amplifier and signal processing circuit, and will be converted into the temperature value of the measured target after being corrected according to the algorithm of the instrument and the target emissivity. In addition, the environmental conditions of the target and thermometer, such as temperature, pollution, pollution and interference, should be taken into account.

① In 1800, infrared radiation was discovered by human beings. After the Second World War, a large number of research and products of thermometers based on the relationship between infrared radiation and surface temperature emerged

② The infrared thermometer measures the temperature according to the infrared emitted by the object;

Infrared thermometer does not emit infrared when measuring temperature

③ All objects emit infrared rays above the absolute temperature (- 273 ℃)

④ The emissivity of each object is different. When using infrared temperature measurement, the emissivity must be set to convert to the correct temperature value

⑤ The infrared thermometer can calculate the infrared quantity by absorption, and remote measure the temperature through telescope. Generally, the commercial model can remote measure the temperature of wire connector hundreds of meters away

2. Application example of infrared thermometer

① Epidemic prevention

Rapid screening of people with abnormal temperature; rapid screening of animals and livestock with abnormal temperature; this has been shown in this year's epidemic.

② Agriculture, animal husbandry and agricultural products

Storage temperature measurement of frozen food; detection of rotten and fermented food or fruit; health temperature management of livestock and pets

③ Architecture

Confirm the heat insulation effect of walls, doors and windows; confirm whether the air circulation of air conditioning and air conditioning is uniform; check whether circuit breakers, wires and sockets are overloaded

④ Detective

Confirm whether someone has used electrical appliances, telephones, computers, automobiles and locomotives in a short period of time.

⑤ Safety inspection of steam turbine

Quickly check whether the tire temperature is abnormal for inflation or pressure relief.

Check the temperature of non working spark plug, flameout cylinder and fuel nozzle.

Diagnose the vehicle cooling system and find the leakage point of cold coal.

Check whether the electrical contact or fuse is abnormal.

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3. Advantages and disadvantages of infrared forehead temperature gun

Infrared temperature measurement is vulnerable to external light and radiation interference. For example, when the ear temperature gun is used as the forehead temperature gun, because of other external light sources and radiation interference, the precision will decline

Advantages of infrared forehead temperature gun:

① Fast temperature measurement: no need to change the protective sleeve, fast operation

② No contact, avoid the discomfort of the subjects, avoid the chance of infection

③ Free of the cost of consumables, no need to add a protective sleeve for temperature measurement, no consumables

④ It can quickly screen individuals with abnormal temperature in the group, and then confirm their true body temperature with an ear temperature gun, saving time and cost

Disadvantages of infrared forehead temperature gun:

① Vulnerable to external light and radiation interference

② The external temperature is easily affected by the ambient temperature, which is different from the actual temperature in the body. (for example, the forehead temperature of a person working in a cold room must be low.)

③ Cosmetics and skin color, because of different infrared emissivity, will affect the display temperature accuracy

Finally, share which substances are suitable for infrared thermometer measurement and which are not suitable for infrared thermometer measurement.

① The following substances have high emissivity and are suitable for infrared thermometer measurement:

Clothing, plastic, glass, pottery, skin, water and water solution, milk, trees, plants, soil

② The following substances have low emissivity characteristics and are not suitable for infrared thermometer measurement:

Gold, aluminum, anything that glows

③ Materials with specular reflection effect are not easy to measure by infrared ray (etc.)

Solution: measure the object that can reflect light, and spray it with non reflecting black paint on the surface of the object