IR thickness gauge for rapidly moving coated foils - has isothermal back body radiator and absorption pyrometer detecting radiation through coating

摘要

The infra-red thickness gauge for coated foils comprises a black-body radiator and an electronic pyrometer. The plastic-coated metal foil can be conveyed at high speed through rollers (10, 11) in close proximity to a hemispherical, isothermal i.r. source (17). The hemispherical space is held at a temp. in the region of 316 deg. C by a thermostatic control (16) and emits i.r. radiation of around 3.4 Microns. The radiation passing through the coating is reflected by the surface of the substrate back through the coating and through a narrow opening (18) in the dome of the radiator. An electronic pyrometer (8) suitably calibrated, detects the radiation and from the absorption due to the coating, the thickness can be determined.