What considerations should be taken into account for the explosion-proof design of flameproof infrared thermal imagers?

Thread Content

An infrared thermal imager is a device that converts the infrared radiation from an object’s surface into a visible image, using an infrared optical system, an infrared detector, and an electronic processing system. It has a temperature measurement function, is capable of quantitatively mapping the temperature distribution on an object’s surface, and performs pseudocolor coding of grayscale images. The products generally include visible light lenses and infrared thermal imaging lenses. An infrared camera uses an infrared detector and an optical imaging lens to capture the pattern of infrared radiation energy distribution from the object being measured, which is then reflected onto the photosensitive elements of the infrared detector; this results in an infrared thermal image that corresponds to the heat distribution pattern on the surface of the object. In simple terms, a thermal imager converts the invisible infrared energy emitted by objects into visible thermal images. The different colors on the thermal image represent the different temperatures of the object being measured. For such products, the explosion-proof treatment generally involves making them flame-retardant type. That is, a product casing is formed using a metal enclosure that complies with GB3836.1 and GB3836.2, along with transparent components. The cable is connected to the internal wiring terminals through an explosion-proof introduction device. Contain the explosive energy within the shell and prevent flames from spreading from the inside to areas with hazardous gases outside. https://pic4.zhimg.com/80/v2-688f2b3ac5745fef1d798c301e597547_720w.jpg But due to the special properties of infrared radiation, germanium glass is typically used as the window in infrared thermal cameras, serving to protect the subsequent optical systems and infrared detectors. However, since the refractive index of germanium material is 4, using it directly results in significant loss of the incident signal. To improve the transmission of infrared signals, a suitable thin film must be coated on the germanium glass to increase the transmittance and protect the surface of the germanium lens. The physical properties of germanium glass are such that it is relatively brittle, meaning its resistance to mechanical impact is not high. In the flameproofing approach, germanium glass must be part of the enclosure and connected to the metal enclosure by adhesive. This requires germanium glass to be able to withstand an impact of at least 4 J without damage, but this is difficult to achieve in practice. So we can try to make the germanium glass smaller and thicker, and we can also add a metal mesh cover on the outside to reduce impacts. In accordance with the provisions of GB3836.1, for transparent components protected by an outer mesh cover, the impact test requirement can be reduced to 2J. For the processing of other sections, simply follow the standard requirements. Original article; plagiarism and reproduction are strictly prohibited!