Abstract: Waste paper is defiberized within a container or receptacle in a thick stock range at a low water level. Thereafter, by further infeeding water, the obtained slurry or the like is diluted to a consistency of less than 7% while continuing the defiberizing operation. Finally, the obtained stock suspension is withdrawn through a sieve or screen located at the floor of a defiberizing container. The defiberizing container or receptacle used for performing the method possesses a lower region having a smaller diameter, above which there is located an upper region having a larger diameter.

Abstract: A method of preparing waste paper wherein the waste paper is defiberized in water within a stock slusher or pulper. Following the stock pulper there is removed from the stock suspension all of the already available good stock fibres by means of a sieve or screen device. The remainder of the stock suspension is then subjected to a comminution action and is again screened. The screening and comminution can take place in a first fiberizer or secondary pulper having a finer sieve or screen than a conventional secondary pulper. The overflow of the first secondary pulper is infed to a second secondary pulper and the overflow thereof is then fed to a dynamic jarrer or vibrator. Forwardly of the dynamic jarrer there is arranged a vat containing a circulation system of a despeckling device.

Abstract: An installation for processing waste paper containing a stock pulper or slusher equipped with a rotor and two sieves or screens having different size holes or openings. By means of the sieve having the larger size openings there is conducted the obtained stock suspension through a primary line system which, for instance, leads to a papermaking machine. Cooperating with the sieve having the larger size openings or holes is an auxiliary circulation circuit containing a device for the removal of contaminants or rejects. There is preferably arranged at the auxiliary circulation circuit or system a separator for heavy contaminants or rejects, a pump, a secondary stock pulper or fiberizer and a sieve or filtering device.