Hollander(redirected from Holländer)
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an apparatus of periodic action used for beating fibrous materials in paper production. The machine was first used in Holland at the turn of the 18th century. A hollander consists of a tank with a volume of 3–18 cu m. The tank is divided into two parts, or channels. A drum equipped with cutting blades is installed in one of the channels; a bedplate of beater bars is mounted under the drum. When the watery suspension (slurry), which contains 3–7 percent fibrous material, passes between the bars of the bedplate and the rotating drum, the material is beaten and transferred by the drum bars through the backfall to the other channel. From this channel the material flows by gravity back to the drum.
Hollanders are used for the manufacture of several types of thin paper. The pulp-and-paper industry is replacing hollanders with more productive continuous-action machines, such as conical and disk refining mills.