Pyrometer Series Metis MY80 and MY84 use pyroelectrical detectors to operate in the long wave band area between 8 and 14 µm. They were developed especially to measure small spot sizes at lower temperatures with fast exhibition times.
The pyrometer model Metis MY 84 is ideally suited to all types of applications like measurement of organic materials, painted metal surfaces, rubber, paper, textiles and thicker plastics.
For non-contact temperature measurement of thin polyester films and all kind of fluorocarbon-plastics, the narrow band model Metis MY80 was developed. It is best choice to measure thin glass surfaces in furnaces because glass is neither transparent nor reflective at 8, 05 µm. It therefore meets the so called “black body conditions” of an ideal radiator.
The infrared energy radiated by the target is centered via focusable or fixed focus lenses directly on the detector. The focusing feature allows control of the cone of vision and offers the possibility to measure either a small spot (focused) or the average of a bigger spot (out of focus). Fixed focus lenses with larger diameter collect more infrared energy and therefore result in smaller spot sizes. The lenses are made of calcium fluoride CaF2 (MY80) or zinc sulphide ZnS (MY84). If additional windows are necessary they must offer similar optical characteristics.
The detector is sensitive to infrared radiation in an area called the cone of vision. For the spot size diameter of the cone of vision at shortest, medium and widest focal distances, please see Chart 2, 3 and 4. For full scale temperatures up to 700°C the cone of vision diameter in front of the lens is about 16 mm and about 8 mm for full scale temperature of 1000°C. This area has to be kept free from any intervening objects. The spot size diameter for distances not given in the chart can be calculated by interpolation.
The MY84 is also available with different fast exposition times of 5, 30, or 100 ms. Slower models offer better optical resolution (smaller spot size).