Abstract: Weathering apparatus with UV radiation sources and radiation sensors containing a double-calibrated UV sensor A weathering apparatus has one or more UV radiation sources (2) and one or more first sensors (3), which are calibrated for a first spectral sensitivity range. In a first aspect of the invention, the sensor or one of the first sensors (3) is calibrated in such a way that the radiation power of a spectral range which is located within the first spectral sensitivity range can be determined from its output signal. In a second aspect of the invention, a second sensor (4) is provided, which is calibrated for a second spectral sensitivity range.

Abstract: A holding frame (2) is mounted in a weathering chamber (1) of a weathering tester so that it can be rotated around a xenon radiation source (3), which is located on the cylinder or rotation axis, and an infrared filter (5) placed around it. Samples (3) to be weathered are fastened to the inside of the holding frame (2) and are exposed to the radiation from the xenon radiation source (4). The surface temperature of the samples (3) can be recorded directly by a black-body radiation detector such as a pyrometer (6), which is aimed at a stationary region of space through which the samples (3) pass periodically during their rotational movement. The surface temperature can be computed in an evaluation circuit from the detected black-body radiation, together with emissivity values stored for the individual samples (3).

Abstract: The usual xenon radiation source in conventional weathering testers is replaced by UV light-emitting diodes (LEDs) (6). These can be used to provide a good approximation of the UV component of the solar spectrum, in particular when different types of UV light-emitting diodes (6) with different emission characteristics are employed. Optionally, further light-emitting diodes in the visible spectral range may also be used in order to cover other parts of the solar spectrum. The light-emitting diodes (6) may be mounted on a flexible printed circuit board (5), which may in turn be fitted on a tubular holding body (4). The flexible printed circuit board carrying the light-emitting diodes may also be placed on other substrates (7) which are pliable in a geometrically stable way, so that that they can be arranged at a uniform distance from material samples with a particular surface topology, in order to obtain uniform exposure.

Abstract: In this method, the surface to be investigated is first of all exposed to collimated light and the radiation rejected therefrom supplied to a position-resolving image processing means. Then, a mask is generated on the basis of the image supplied by the image processing means, said mask having masked regions being defined by relatively bright areas of said image and unmasked regions being defined by relatively dark areas of said image. Now, the surface to be investigated is exposed to diffuse light and the radiation rejected therefrom supplied to the image processing means, with only the radiation from the unmasked regions being taken into consideration for analyzing purposes.

Abstract: Calibrating temperature sensors of weathering devices by means of contactless temperature measurement A temperature sensor (10) which is, for example, designed as a black standard sensor and is typically used in apparatuses for artificial weathering of material samples, has in a known way a stainless steel plate (1) which is provided with a black coating (2) and is thermally coupled at its rear side to a platinum resistor (3). The output signal of the electric measurement transducer circuit connected to the platinum resistor (3) by means of feeder wires (4) can be calibrated with the surface temperature measured in a contactless fashion by a pyrometer (8). The calibration operation can be carried out under the conditions prevailing in a weathering device, that is to say while applying to the surface of the sensor the optical radiation of a xenon radiation source (7) and an airstream (9) parallel to the surface.

Abstract: A plug-in radiation source module (10) for mounting and locating a radiation source (3) for a weathering apparatus (20), the plug-in module (10) being configured to be insertable from without into a cavity (21) provided therefor in a weathering apparatus (20).

Abstract: The radiation power emitted from the UV radiation sources (2) in a weathering apparatus is controlled such that the radiation power of each of the radiation sources (2) is measured in a predetermined spectral range of the radiation emitted from the radiation sources, with the spectral range being chosen such that the measured radiation power is representative of the radiation power in the UV, an averaged radiation power is calculated from the measured radiation powers, and the averaged radiation power is used for controlling the electrical power to be supplied to the radiation sources (2). In particular, the control process can be carried out in such a way that the same electrical power, within a predetermined tolerance bandwidth, is supplied to each of the radiation sources (2), and the averaged radiation power is kept constant over time at a desired nominal value.

Abstract: Weathering apparatus with UV radiation sources and radiation sensors containing a double-calibrated UV sensor A weathering apparatus has one or more UV radiation sources (2) and one or more first sensors (3), which are calibrated for a first spectral sensitivity range. In a first aspect of the invention, the sensor or one of the first sensors (3) is calibrated in such a way that the radiation power of a spectral range which is located within the first spectral sensitivity range can be determined from its output signal. In a second aspect of the invention, a second sensor (4) is provided, which is calibrated for a second spectral sensitivity range.

Abstract: A holding frame (2) is mounted in a weathering chamber (1) of a weathering tester so that it can be rotated around a xenon radiation source (3), which is located on the cylinder or rotation axis, and an infrared filter (5) placed around it. Samples (3) to be weathered are fastened to the inside of the holding frame (2) and are exposed to the radiation from the xenon radiation source (4). The surface temperature of the samples (3) can be recorded directly by a black-body radiation detector such as a pyrometer (6), which is aimed at a stationary region of space through which the samples (3) pass periodically during their rotational movement. The surface temperature can be computed in an evaluation circuit from the detected black-body radiation, together with emissivity values stored for the individual samples (3).

Abstract: The usual xenon radiation source in conventional weathering testers is replaced by UV light-emitting diodes (LEDs) (6). These can be used to provide a good approximation of the UV component of the solar spectrum, in particular when different types of UV light-emitting diodes (6) with different emission characteristics are employed. Optionally, further light-emitting diodes in the visible spectral range may also be used in order to cover other parts of the solar spectrum. The light-emitting diodes (6) may be mounted on a flexible printed circuit board (5), which may in turn be fitted on a tubular holding body (4). The flexible printed circuit board carrying the light-emitting diodes may also be placed on other substrates (7) which are pliable in a geometrically stable way, so that that they can be arranged at a uniform distance from material samples with a particular surface topology, in order to obtain uniform exposure.

Abstract: Calibrating temperature sensors of weathering devices by means of contactless temperature measurement A temperature sensor (10) which is, for example, designed as a black standard sensor and is typically used in apparatuses for artificial weathering of material samples, has in a known way a stainless steel plate (1) which is provided with a black coating (2) and is thermally coupled at its rear side to a platinum resistor (3). The output signal of the electric measurement transducer circuit connected to the platinum resistor (3) by means of feeder wires (4) can be calibrated with the surface temperature measured in a contactless fashion by a pyrometer (8). The calibration operation can be carried out under the conditions prevailing in a weathering device, that is to say while applying to the surface of the sensor the optical radiation of a xenon radiation source (7) and an airstream (9) parallel to the surface.

Abstract: A method for determining the time curve of the intensity of radiation present at the location of at least one sample which is being examined. The sample follows a circular path of movement in a sealed sample chamber of a weathering testing device, around a stationary radiation device for producing UW and global radiation. At least one sensor which detects the momentary radiation intensity of the radiation device is provided. The sensor moves together with the at least one sample, and is displaced in relation thereto in relation to the radiation device, for example in the peripheral direction of the path of movement. An electrical signal corresponding to the momentary intensity of the radiation is derived by the sensor at set intervals.