Abstract: An apparatus for sorting paper materials includes a separating mechanism for thinning the paper materials and a sensing mechanism for classifying the paper material according to type. The separating mechanism includes a plurality conveyor belts operating at successively higher speeds, whereby passing materials from one conveyor belt to another conveyor belt results in spreading the paper material. The sensing mechanism includes a mechanical striking device to strike the paper material, a microphone to detect the sound caused by the striking device and an evaluation unit to determine the type of paper material on the basis of the sound.

Abstract: A plug for the mouthpiece of a wooden recorder, molded integral from plastic material, has a concave and a flat end wall interconnected by side and intermediate walls. A lower side wall, or an intermediate wall parallel thereto, has one or two outer humps designed to contact the inner mouthpiece surface and is sufficiently deformable to flex inward upon insertion into the mouthpiece.