Abstract: A device for detecting properties of a moving web of paper, more specifically for production control in the paper making process, comprising an infrared lighting device suited for illuminating the web of paper with infrared light and a detector device for detecting light reflected or transmitted by the web of paper which is provided with a light input portion. The infrared lighting device is provided with a light source in the form of a long, rod-shaped infrared emitter, the light source being accommodated in a housing having a front plate facing the web of paper. An exit window, through which the light from the light source passes to impinge upon the web of paper, is tight-fittingly received in an aperture in the front plate.

Abstract: The invention relates to a device for detecting properties of a moving web of paper, more specifically for production control in the paper making process, with an infrared lighting device suited for illuminating the web of paper with infrared light and provided with a light exit portion, with a detector device for detecting infrared light reflected or transmitted by the web of paper which is provided with a light input portion and with a housing a) which is arranged in immediate proximity to the paper web, b) which is provided with a front face facing the web of paper and c) which accommodates the light exit portion and/or the light input portion provided with optical fibers. A plurality of n spherical lenses is arranged in a sealed manner in the front face, said spherical lenses being each optically coupled to an allocated optical fiber within the housing, said spherical lenses constituting, together with the corresponding optical fibers, the light exit portion and/or the light input portion.

Abstract: An infrared detector device for a device for detecting properties of a moving web of paper, more specifically for a device for controlling production in the paper making process, the detector device being provided, on the one side, with a polychromator that receives, on its receiving side, light coming from the web of paper and, on the other side, with an infrared detector with a matrix of infrared sensitive photoconductors, an evaluation electronic unit with one memory assigned to a respective one of the photoconductors of the matrix being connected downstream thereof. An additional source of light that can be controllably switched on and off between a first light intensity and a second light intensity which is greater than the first one uniformly illuminates the infrared detector for deriving correction values for correcting the signals from each of the photoconductors during a measurement.

Abstract: A device for detecting properties of a web of material has a crossbar extending across the web of material. An infrared spectrometer having a holographic grating is provided an has an input side and an output side. Infrared detectors are arranged at the output side of the infrared spectrometer and are formed by a detector matrix having n lines and m rows of infrared sensitive individual sensors. A plurality of optical waveguides are provided, each waveguide having an entrance area and an exit area. The entrance area is fastened to said crossbar, located in vicinity of the surface of the web of material and is oriented towards said surface. The exit areas of the optical waveguides are connected to the input side of the infrared spectrometer.

Abstract: An infrared detector device for a device for detecting properties of a moving web of paper, more specifically for a device for controlling production in the paper making process, the detector device being provided, on the one side, with a polychromator that receives, on its receiving side, light coming from the web of paper and, on the other side, with an infrared detector with a matrix of infrared sensitive photoconductors, an evaluation electronic unit with one memory assigned to a respective one of the photoconductors of the matrix being connected downstream thereof. An additional source of light that can be controllably switched on and off between a first light intensity and a second light intensity which is greater than the first one uniformly illuminates the infrared detector for deriving correction values for correcting the signals from each of the photoconductors during a measurement.

Abstract: A device for detecting properties of a moving web of paper, more specifically for production control in the paper making process, comprising an infrared lighting device suited for illuminating the web of paper with infrared light and a detector device for detecting light reflected or transmitted by the web of paper which is provided with a light input portion. The infrared lighting device is provided with a light source in the form of a long, rod-shaped infrared emitter, the light source being accommodated in a housing having a front plate facing the web of paper. An exit window, through which the light from the light source passes to impinge upon the web of paper, is tight-fittingly received in an aperture in the front plate.

Abstract: The spectroscopic process uses a detector in the form of a linear array of detector units made of a photoconductive semiconductor material, wherein a radiation sample is broken down into its spectrum; the spectrum thus obtained is used to illuminate the detector and is evaluated making use of the dependence of the conductivity of the semiconductor material on the radiation intensity; the beam path between the sample and the detector is periodically interrupted by a chopper to generate dark and bright phases; when at least one measuring cycle is conducted, a measuring cycle is determined during both the dark and bright phases in one measuring period, and the intensity of the radiation impinging on the detector in the bright phase is found from the comparison between the dark phase and light phase; the interruptions in the radiation and the measuring periods are mutually synchronized so a measuring period lies either within a bright or within a dark phase, with the measuring period being variable and adjustable