FIELD: checking fiber samples for impurities. SUBSTANCE: device for checking impurities in sample composed of fibers and impurities has balance for weighing the sample, its weight being transmitted to computer. Then sample is conveyed to sensing space and optical sensor generates output signal corresponding to at least presence of impurity in sensing space. In first version of implemented invention, output signal is presented as light dimming due to presence of impurities in sensing space. In second version, image of impurities is analyzed resulting in output signal corresponding to size, shape, or composition of impurities. Weight information and output signal of optical sensor are entered in computer which yields output data in the form of quantity of at least some portion of impurities per sample weight unit. Computer also displays information in the form of effective diameter, projected area, and weight of impurities, as well as quantity and weight of fibers or relevant information. In particular, computer classifies impurities and displays information about particular category of impurities. EFFECT: improved validity of check results. 6 cl, 12 dwg
