Abstract: The device for examining a solid, elongate product to be tested contains a measurement capacitor with a measurement part-electrode and guard electrodes electrically insulated therefrom. The device further comprises means for applying an alternating voltage to the measurement capacitor for the purpose of generating an alternating electrical field in the measurement capacitor. The guard electrodes are set up for active guarding, in that, with regard to the alternating voltage, they are kept at the same potential as the measurement part-electrode. Differently thick products to be tested may be tested with one and the same measurement head thanks to the active guarding. The signal noise is reduced, the output signal is largely independent of the position of the product to be tested in the transverse direction, and the measurement head has small geometric dimensions.

Abstract: The invention relates to a device for scanning a thread, which is displaceable in the longitudinal direction thereof inside a measuring slot, by means of an optical beam emitted by a light source. The device includes a receiver of light reflected on the thread and a unit for processing electrical signals received by the receiver. The aim of the invention is to develop a small-sized device which is easy to operate and which makes it possible to detect foreign matter contained in the thread in a most selective manner at a high sensitivity. For this purpose, the light emission in at least two wavelength ranges is carried out by means of a light source, with these wavelength ranges being determined by two main wavelengths.

Abstract: The invention relates to a method for detecting and classifying foreign material in an inspection lot of textile fibers that is moved lengthwise. The aim of the invention is to allow for the simultaneous inspection of the inspection lot with regard to a plurality of properties and to allow for the detection of a foreign material and for its classification in a simple manner while taking due consideration of all properties measured. According to the invention, values for deviations of these properties from a standard are detected and stored for at least two properties that are influenced by the foreign material. The values for the deviations are eliminated according to a predetermined rule except for the values of one property. A value for the deviation and a value for the length of the deviation on the inspection lot resulting from the values of the remaining property is detected and the foreign material is classified according to this deviation and length.

Abstract: The invention relates to a method for detecting and classifying foreign material in an inspection lot of textile fibers that is moved lengthwise. The aim of the invention is to allow for the simultaneous inspection of the inspection lot with regard to a plurality of properties and to allow for the detection of a foreign material and for its classification in a simple manner while taking due consideration of all properties measured. According to the invention, values for deviations of these properties from a standard are detected and stored for at least two properties that are influenced by the foreign material. The values for the deviations are eliminated according to a predetermined rule except for the values of one property. A value for the deviation and a value for the length of the deviation on the inspection lot resulting from the values of the remaining property is detected and the foreign material is classified according to this deviation and length.

Abstract: The invention relates to a device for scanning a thread, which is displaceable in the longitudinal direction thereof inside a measuring slot, by means of an optical beam emitted by a light source. The device includes a receiver of light reflected on the thread and a unit for processing electrical signals received by the receiver. The aim of the invention is to develop a small-sized device which is easy to operate and which makes it possible to detect foreign matter contained in the thread in a most selective manner at a high sensitivity. For this purpose, the light emission in at least two wavelength ranges is carried out by means of a light source, with these wavelength ranges being determined by two main wavelengths.