Is the infrared thermometer measuring the temperature of the object behind the glass accurate?
It can accurately measure the temperature of the object behind the glass, and can also accurately measure the temperature of the glass surface. The key is to set the receiving wavelength of the thermometer. Because the thermometer infers the temperature of the object based on the radiation intensity of a certain wavelength of the hot object. To measure temperature through glass, the receiving wavelength of the thermometer should be adjusted to 1.2~2.0 microns. To measure the temperature of the glass itself, the receiving wavelength of the thermometer should be adjusted to 5.0~7.5 microns. How to adjust the wavelength? The wavelength of some thermometers is factory-set, and some are given a range for you to choose when you use it. Just take a screenshot on *bao, and note that it has a spectral range of 8~14 microns:
Why choose different wavelengths to switch to measure the temperature of the glass itself or the temperature of the object behind the glass? This depends on the transmittance of the glass (see the figure below). In the short-wave range (0.2 microns to 2 microns), the glass is almost 100% One hundred transparent. In other words, infrared thermometers can "see" hot objects through glass. But in the long-wave range (greater than 4 microns), the transmittance of glass is almost 0. At this time, the glass is equivalent to a brick blocking the objects behind it. If you use an infrared meter to measure the temperature of the glass, you can only measure the temperature of the glass itself.
When the car is running, the locomotive bearings will heat up due to mechanical friction. When the bearings are in good condition, it is normal for the temperature to rise to a certain extent. When the temperature rises abnormally, it means that the motion state of the bearing is deteriorating, the friction and wear are serious, the lubrication quality is reduced, and the bearing is broken and deformed. In more serious cases, it will cause the train to cut the axle and burn the axle accident. The generation of thermal axis phenomenon undoubtedly brings great potential safety hazard to railway traffic safety. In order to actively avoid the hidden dangers brought by this phenomenon to driving safety, people have been devoting themselves to the research of the axle temperature detection system for many years. The infrared shaft temperature detection system is one of the non-contact shaft temperature detection methods developed by people.
Shaft temperature online detection system Objects above absolute zero have energy radiation corresponding to the temperature, and the radiation intensity increases with the increase of temperature, and the radiation peak wavelength shifts to the short wave direction. The total energy radiated from the surface of an absolute black body is proportional to the fourth power of its surface temperature T, and the temperature can be obtained by detecting the radiated energy. When the temperature is hundreds to thousands of degrees, the radiation spectrum is mainly in the infrared band. Therefore, the temperature of the object can be obtained by detecting the radiant energy in a specific infrared band. The equipment made by using this principle is radiation infrared temperature measuring equipment.
On the basis of the function of axle temperature detection (mainly measuring axle and bearing temperature), it is also possible to adjust the installation angle of the sensor to detect the wheel surface temperature at the same time. When the vehicle passes, it scans the temperature from the wheel tread to the rim to prevent Hot wheels caused by brake shoe lockup or other reasons. The shaft temperature is quantitatively forecasted according to the three-level alarm temperature of mild heat, strong heat and extreme heat, and information alarms.
