| 摘要 |
<p>The apparatus (1) has a knocking element (13), and a suction mouth (8) connected with a suction pipe (2), where the suction element is arranged in an inner side of the suction mouth. The knocking element is provided with two dimensional-elements (14), where dimension of the two-dimensional elements corresponds to more than 60 percent of the dimension of the suction mouth in a breadth direction and in a longitudinal direction during central suction. The knocking element is connected with vertical wall sections of a housing section in a sealing manner.</p> |
