Abstract: A screen for the screening of pulp suspensions is disclosed, including a screen basket, a rotor for providing pressure and suction pulses in the suspension to be screened along the screen basket, and a dilution liquid header for supplying dilution liquid to counteract thickening of the suspension during operation. The header forms a tubular channel, which divides the screen basket into at least two parts, extends around the basket, and is provided with a plurality of dilution ejection nozzles. Each ejection nozzle forms a channel including at least two channel sections; namely, an entrance channel section that opens into the channel of the header, and an exit channel section downstream of the entrance channel section, wherein the entrance channel section is substantially wider than the exit channel section.

Abstract: Screening apparatus for screening pulp suspensions is disclosed comprising a screen basket dividing the interior of the housing into a central chamber and a single outer annular chamber. The suspension is supplied to one of the outer and central chambers, so that an accept fraction passes through the screen, while a reject fraction develops that is prevented from passing through the screen. Dilution is provided by supplying diluting liquid to dilute the reject fraction. The screen basket is divided into at least two separate tubular screen sections. The dilution is provided by at least one annular element axially interconnecting the two tubular screen sections and forming a tubular dilution liquid compartment extending at least substantially around the screen basket. The annular element forms a plurality of dilution liquid ejection passages between the dilution liquid compartment and one of the outer and central chambers.

Abstract: A screen for the screening of pulp suspensions is disclosed, including a screen basket, a rotor for providing pressure and suction pulses in the suspension to be screened along the screen basket, and a dilution liquid header for supplying dilution liquid to counteract thickening of the suspension during operation. The header forms a tubular channel, which divides the screen basket into at least two parts, extends around the basket, and is provided with a plurality of dilution ejection nozzles. Each ejection nozzle forms a channel including at least two channel sections; namely, an entrance channel section that opens into the channel of the header, and an exit channel section downstream of the entrance channel section, wherein the entrance channel section is substantially wider than the exit channel section.

Abstract: A screening apparatus for screening pulp suspensions is disclosed, comprising a housing, a screen basket having a tubular mantle wall with screen apertures, the mantle wall dividing the interior of the housing into a central chamber and an outer substantially annular chamber, and a rotor arranged in the housing for providing pressure and suction pulses in the suspension to be screened along the mantle wall. At least one elongated support element connects the screen basket to the housing and at least one load sensor is arranged on the support element for sensing the load exerted by the screen basket on the support element during operation of the apparatus. A control unit controls at least one operating parameter, such as the consistency of the suspension or rotational speed of the rotor, during operation in response to signals from the load sensor.

Abstract: Screening apparatus for screening pulp suspensions is disclosed comprising a screen basket dividing the interior of the housing into a central chamber and a single outer annular chamber. The suspension is supplied to one of the outer and central chambers, so that an accept fraction passes through the screen, while a reject fraction develops that is prevented from passing through the screen. Dilution is provided by supplying diluting liquid to dilute the reject fraction. The screen basket is divided into at least two separate tubular screen sections. The dilution is provided by at least one annular element axially interconnecting the two tubular screen sections and forming a tubular dilution liquid compartment extending at least substantially around the screen basket. The annular element forms a plurality of dilution liquid ejection passages between the dilution liquid compartment and one of the outer and central chambers.

Abstract: A tubular screen for screening of pulp suspensions comprises a mantle wall (1), which is provided with screen passages, and external support rings (6), which reinforce the mantle wall so that the latter is resistant to and is not deformed by dynamic forces during operation. Each support ring is designed with a conical surface (7), which abuts and presses directly or indirectly against the mantle wall (1).

Abstract: A process for the purification of a fiber suspension (deinking or white water) in which a mixture of fiber suspension and gas bubbles are jtted into a flotation tank in an upwardly directed manner toward the free surface of the pulp at a velocity of greater than Sm/s and the jet ends at or just below the free surface of the mixture.

Abstract: Apparatus for screening pulp suspensions containing heavy impurities is disclosed including a casing with an inlet for the pulp suspension at the lower end of the casing, a stationary screen mounted within the casing, a rotor mounted for rotation within the stationary screen thus forming a screening zone between the rotor and the stationary screen, with the inlet disposed within the rotor, the rotor including at least one opening adjacent to its upper end for transferring the pulp into the screening zone and a chamber for the heavy impurities disposed adjacent to either the upper or lower end of the casing, the rotor including strips or grooves for moving heavy impurities from the inner surface of the rotor to the chamber.

Abstract: Apparatus for separating light impurities from a pulp suspension is disclosed. The apparatus includes a housing mounted on a fractionation device and symmetrically disposed with respect to the axis of rotation of the casing of the fractionation device, a passageway extending between the housing and the casing, and in which the top of the housing includes an outlet for the light impurities and a dilution liquid inlet for injecting dilution liquid tangentially into the housing.

Abstract: Methods and apparatus are disclosed for uniformly distributing a flowing medium flowing in a first direction in a conduit onto a surface so as to form a uniformly distributed medium thereon having a width greater than that of the conduit, the method including deflecting the flow of the flowing medium and simultaneously spreading the flowing medium from the width of the conduit to the greater width in a direction transverse to the first direction, and again deflecting the flowing medium in a passage having a generally curvilinear shape transverse to the surface in order to provide a substantially uniformly distributed and parallel flow of the flowing medium onto the surface.

Abstract: Methods for mixing a treatment agent with a pulp suspension are disclosed including supplying the pulp suspension to a mixing chamber, moving the pulp suspension through a mixing zone with the mixing chamber, supplying the treatment agent to the moving pulp suspension across the entire width of the mixing chamber prior to the mixing zone, and in which the height of the mixing zone is sufficiently small such that the pulp suspension and the treatment agent are subjected to kneading within the mixing zone in order to repeatedly stretch and compress fiber flocks in the pulp suspension. Apparatus for mixing the treatment agent with the pulp suspension are also disclosed.

Abstract: A papermaking machine is constructed as a barrier former in which a fiber slurry is received and placed in turbulence on one side of the screen plate for fluidizing the slurry and distributed through the screen plate onto a collecting wire, under tension, for immediately starting dewatering of a web formed in a wedge-shaped forming zone between the screen plate and the wire.

Abstract: A plurality of fluent substances are combined in a distributor (11, 37) and caused to flow in a continuous, pressurized stream through a mixing zone (13, 13', 57) wherein the substances are intimately mixed by turbulent dispersion effected by a series of conically shaped surfaces (24, 27; 62, 64) and alternate restrictions (25, 63) and expansion chambers (28, 65). While various fluent substances may be advantageously mixed, a typical utility is for effecting a thorough air binding of ink particles to attain efficient foaming (29) in the deinking of reconstituted printed paper slurry.

Abstract: A plurality of fluent substances are combined in a distributor (11, 37) and caused to flow in a continuous, pressurized stream through a mixing zone (13, 13', 57) wherein the substances are intimately mixed by turbulent dispersion effected by a series of conically shaped surfaces (24, 27; 62, 64) and alternate restrictions (25, 63) and expansion chambers (28, 65). While various fluent substances may be advantageously mixed, a typical utility is for effecting a through air binding of ink particles to attain efficient foaming (29) in the deinking of reconstituted printed paper slurry.

Abstract: A method and apparatus for removing stringy contaminants from a pulp in a wastepaper recovery system having a pulping vat with an elongate helically shaped rod in the vat with means for causing a relative rotation between the stock and the helical rod so that long slender contaminants will be captured and climb the rod. In one form, multiple helices are employed and the rods may be driven in rotation, or the stock caused to rotate about the helix by other means.

Abstract: A paper stock refiner provides low intensity treatment of pulp fiber to increase the strength characteristics of the pulp while reducing the specific energy required through increasing the number of refining surfaces. The number of refining surfaces is accomplished by providing a plurality of rotatable (30) and non-rotatable (36) refiner disks which are axially movable within a refiner, the rotatable disks being mounted on a torque transmitting section (28) of a shaft (26) and the non-rotatable disks being mounted against rotation on a plurality of supporting elements (44). In order to control the number of refiner bar crossings, the housing (12) may be opened and a desired number of refiner disks, both rotating and non-rotating, may be loaded into the refining chamber (16) on the shaft and the support elements, respectively.