Keller HCW GmbH (Ibbenbüren, Germany):

Book A., Mag. Eng., Head of MSR FFS Business Area, e-mail: albert.book@keller-msr.de

Infrared pyrometers with contact-free and quick registration of measurement results are ideally suitable for temperature measuring during induction heating. In this case operator can choose between the two measuring methods: using one wave or two waves. The paper observes differences between these two methods from the point of view of measuring techniques, optical aspects, maintenance of sensors and their influence on measurement quality. Technical innovations that simplify registration of measurement results are presented. It is shown that single-channel pyrometers provide good measurement results at stable technological conditions, such as size of measuring object, its distance, material and surface quality. High-quality optical system is required for minimization of optical defects, and dimensions of the object or heating zone should be larger that the measuring field of pyrometer at least by 3-5 times. Spectral pyrometer on short waves allows to decrease material and surface quality infl uence on measurement results. To provide high precision of measuring, operating reliability and tuning simplicity, we have to use logometric pyrometers. Dual-channel measuring method is preferable for the cases with variable technological conditions or measuring locations, as well as for expected effect of steam, dust and other contaminants. However, logometric pyrometers are more expensive (by 50–100%), due to more complicated scope of supply.