Utilizing and Applying Common Sense to Infrared Thermometers
Due to the interference of weather conditions, improper human operation, and other factors during the use of infrared thermometers, it directly affects the screening of individuals with fever. To ensure that all checkpoints, business operators, markets, medical institutions, factories, and school supervisors in the entire district can effectively utilize infrared thermometers during the epidemic period, guide the public to use thermometers in a scientific and standardized manner, and assist in screening personnel returning to work, production, and school in our district, we will introduce and promote their usage methods to users.
1. Infrared thermometers cannot measure temperature through glass, as glass has unique reflection and transmission characteristics that do not allow for accurate infrared temperature readings. But temperature can be measured through an infrared window. It is best not to use infrared thermometers for temperature measurement on bright or polished metal surfaces (such as stainless steel, aluminum, etc.).
2. Infrared thermometers can only measure the surface temperature of objects and cannot measure their internal temperature.
3. Be careful to locate hotspots, identify hotspots, aim them at the target, and then perform up and down scanning movements on the target until the hotspot is determined.
4. We should pay attention to environmental conditions such as smoke, steam, dust, etc. when using it. They all block the optical system of the instrument and affect accurate temperature measurement.
5. When using an infrared thermometer, attention should also be paid to the ambient temperature. If it is suddenly exposed to an ambient temperature difference of 20 degrees or higher, the instrument is allowed to adjust to the new ambient temperature within 20 minutes.
When using an infrared thermometer to measure temperature, the infrared energy emitted by the object being measured is converted into an electrical signal on the detector through the optical system of the infrared thermometer. The temperature reading of this signal is displayed, and there are several important factors that determine accurate temperature measurement. The most important factors are emissivity, field of view, distance to the light spot, and position of the light spot. Emissivity, all objects reflect, transmit, and emit energy, and only the emitted energy can indicate the temperature of the object. When an infrared thermometer measures surface temperature, the instrument can receive all three types of energy. So, all infrared thermometers must be adjusted to read only the emitted energy. Measurement errors are usually caused by the infrared energy reflected by other light sources. Some infrared thermometers can change emissivity, and emissivity values for various materials can be found in published emissivity tables. Other instruments have a fixed emissivity of 0.95. The emissivity value is compensated for the surface temperature of most organic materials, paints, or oxidized surfaces by applying a tape or flat black paint to the tested surface. When the tape or paint reaches the same temperature as the base material, measure the surface temperature of the tape or paint to obtain its true temperature. The ratio of distance to spot, the optical system of an infrared thermometer collects energy from a circular measuring spot and focuses it on the detector. The optical resolution is defined as the ratio of the distance from the infrared thermometer to the object to the size of the measured spot (D: S). The larger the ratio, the better the resolution of the infrared thermometer, and the smaller the size of the measured light spot. Laser aiming is only used to assist in aiming at the measurement point. The latest improvement in infrared optics is the addition of near focus characteristics, which can provide accurate measurement of small target areas and prevent the influence of background temperature. Field of view, ensuring that the target is larger than the spot size measured by the infrared thermometer. The smaller the target, the closer it should be. When accuracy is particularly important, ensure that the target is at least twice the size of the light spot.
