| 摘要 |
A method for laying down a continuous, predetermined pattern of granular material upon a moving substrate (12) includes moving the substrate past at least two stations, each station including a rotating drum (18) with a drum wall (20) defining a limited retention region under vacuum (34) and a plurality of through-apertures (36) arranged in an element of the desired pattern. Granular material (G) applied to the surface of the drum is held by vacuum in the desired pattern. After removal of excess granular material, th e vacuum is discontinued causing the granular material to disengage from the drum surface and pass, by force of gravity, onto the surface of the substrat e in the form of the predetermined element of the desired predetermined patter n. An apparatus for laying down a continuous, predetermined pattern of granular material upon a moving substrate is also described.
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