<p>The shrinking device (1') has shaft walls which are provided with a width and a cross-sectional area perpendicular to the transport direction (TR) in an area (A-A) of a transport path. The shaft walls have another width and another cross-sectional area perpendicular to the transport direction in another area (B-B) of the transport path. The former cross-sectional area is smaller than the latter cross-sectional area.</p>
