Waste paper contains sticky foreign material, and the recovery and sending of this sticky foreign material to a paper-making process together with fiber is liable to lead not only to the sticky foreign material sticking to and contaminating the paper making machine or dryer but also paper peeling and tearing, causing a decline in paper quality. This method for recovering fiber form a screening reject is characterized by comprising the steps of: sending a screening reject coming out from a coarse sorting process to a fine sorting pre-processing process such that the screening reject is impacted against rotating blades 8 or stationary blades 11 in the interior of a cylinder body 2 and detachment of the fibers from the sticky foreign material by the sticky foreign material being kneaded and granulation and balling-up of the detached sticky foreign material are promoted, taking advantage of the sticky foreign material becoming extendable and shrinkable due to softening in an environment in which heat is generated from friction between fibers; and then sending the result to the fine sorting process so that the fiber is recovered with the balled-up sticky foreign material being separated as a screening reject via the fine sorting process.

A stirring device has a storage tank and a stirring member that stirs an inside of the storage tank, and the stirring member has a humidified air release port through which humidified air, which is air humidified, is released into the storage tank.

There is provided a crushed piece supply device including a storage tank that stores a crushed piece containing a fiber, a partition portion that partitions an inside of the storage tank into a first space and a second space positioned below the first space by narrowing the inside of the storage tank, an adjusting section that adjusts a moving amount of the crushed piece moving from the first space to the second space, a stirring section that stirs the crushed piece in the second space, and a discharge port through which the crushed piece is discharged from the second space.

A method and a device for pulping fibrous materials is particularly suited for pulping waste paper. The method and the device are especially configured for the pulping of high pulp consistencies of more than 8%. The fibrous materials are added to a horizontally arranged pulper, being a drum or a trough, as a function of a fill level in the pulper. The fill level is measured in the pulper at least at two axially spaced-apart locations in the trough or the drum of the pulper.

A pulper for producing a pulp suspension from paper, solids and water, including a cylindrical container for holding a main part of the pulp suspension and having a container wall and a container bottom, and a rotor arranged in an interior of the container for disintegrating the pulp fed into the container and for producing an aqueous suspension. The container wall has, as seen in plan view and/or in a horizontal section, the shape of a triangle with rounded corner regions, at least one of the corner regions is configured such that a flow deflection of less than 90 occurs during operation, the container wall between two corner areas is flat or curved with a radius of curvature that is greater than that of the two corner regions, and the pulper is free of additional containers located outside of the container.

A method for operating a screening device for cleaning a fibrous suspension includes the steps of: providing that the screening device includes a housing, a rotor arranged in the housing, and a screen; feeding the fibrous suspension and a rinsing water to the screening device; passing a portion of the fibrous suspension through the screen; discharging the portion of the fibrous suspension passing through the screen via an accepted stock discharge; and regulating, depending on a power consumption of a rotor drive, at least one of an inflow into the screening device and a cycle duration.

A fiber processing system includes a fiber processing unit having an inlet, accepts outlet, and solid discharge outlet and configured to remove solid contaminants from a fiber-containing stream to produce an accepts stream exiting the accepts outlet and a solid discharge stream exiting the solid discharge outlet. The fiber processing system includes an optical system having an imaging device and image processing system. The imaging device is configured to capture images of the solid discharge stream at or downstream of the solid discharge outlet, and the image processing system is configured to determine relative fiber content, a relative generation rate, types of materials in, or combinations thereof of the solid discharge stream from the captured images. The fiber content, generation rate, and/or types of materials of the solid discharge stream are used to control operation of the fiber processing system or other upstream pulp processing equipment.

A defibering and deflaking pulper has a defibering rotor-stator pair and a deflaking rotor-stator pair for processing a fiber-based material into smaller pieces. The defibering and deflaking pulper creates an impeller-produced vortical circulation that pulls the material through a defibering rotor-stator interface, where the material is broken down into smaller pieces, and then through a deflaking rotor-stator interface, where the smaller pieces are broken down into even smaller pieces. The defibering and deflaking pulper accumulates the defibered and deflaked material that passes through the defibering rotor-stator interface and the deflaking rotor-stator interface for further processing. This combination of defibering and deflaking in the defibering and deflaking pulper reduces plugging from larger pieces of the material and reduces downstream processing of the material, thus increasing productivity and reducing costs.